JP4946801B2 - Image management apparatus, image management program, and image management method - Google Patents

Description

  The present invention relates to an image management apparatus, an image management program, and an image management method for managing compressed data of a plurality of images.

  2. Description of the Related Art In recent years, it has become possible to photograph a cross section of a human body with a narrow slice interval of less than 1 mm due to high performance of diagnostic imaging apparatuses such as CT (Computed Tomography) and MR (Magnetic Resonance). In such an image diagnostic apparatus, a multi-slice image composed of a plurality of frames is obtained as a captured image obtained by one examination. A multi-slice image is obtained by continuously capturing cross-sectional images while changing the coordinates of an axis perpendicular to the plane of the cross-sectional image (frame) for each slice interval. When the slice interval is narrowed, the number of frames of a multi-slice image obtained by one inspection increases, and the number of frames reaches several hundred to several thousand and the data capacity reaches several hundred MB (Byte).

  The captured multi-slice image is stored in an image server installed in a computer room of a medical institution, transferred to a client terminal via a network at the time of interpretation or examination, and displayed / referenced. In addition, since medical images used for medical examination are required to be stored for a long period by law, the storage capacity tends to increase every year. For this reason, it is essential to compress medical images in order to improve the number of images stored in the image server. Further, there is a strong demand for medical images to store captured images without deterioration, and lossless (reversible) compression is often used as a compression method.

  Conventional lossless image compression methods for medical images include lossless JPEG (Joint Photographic Experts Group), JPEG-LS (Lossless), JPEG2000, and the like. At present, lossless JPEG is most widely used, and JPEG2000 is used in part.

  Lossless JPEG is a method of calculating a predicted value of a pixel of interest using 1 to 3 pixels out of three pixels in the vicinity of the pixel of interest and Huffman encoding a difference from the pixel of interest. There are seven types of prediction methods, and one type of predictor is selected and used for each image. Although the compression rate depends on the image, it is about 1/2 to 1/3 for a medical image.

  JPEG2000 is a compression method using Discrete Wavelet Transform (DWT). After DWT is applied to an image and converted to frequency space, the converted data is modeled to increase entropy encoding efficiency and then arithmetic encoded. To do. The compression rate for medical images is higher than that of lossless JPEG, and is about 1/3 to 1/4.

  JPEG-LS is a method for obtaining a prediction value of a pixel of interest from four pixels in the vicinity of the pixel of interest and performing Golomb encoding of a prediction error. A prediction method is selected from three types of prediction methods for each pixel according to the value of the pixel of interest. The compression rate of medical images is similar to that of JPEG2000.

  The above-described lossless image compression method is a method in which compression is performed independently for each image, but a method using three-dimensional DWT as a compression method for medical images having a correlation between frames such as a multi-slice CT / MR image. Has been proposed. A higher compression ratio can be realized than the above-described method of compressing in units of images.

As a related art related to the present invention, there is an image data compression method for compressing a plurality of tomographic images and frame images constituting a moving image (see, for example, Patent Document 1).
JP 2005-245922 A

  However, the multi-slice CT / MR image detects the X-ray dose transmitted through the human body by the sensor provided outside the human body, the radiation dose from the radioactive material administered into the body, etc. This state is reconstructed and visualized as an image, and features are greatly different from a natural image obtained by directly photographing a subject.

  In particular, noise caused by sensors or reconstruction that occurs in a captured image is not usually present in a natural image. As an example of remarkable noise, there is radial noise generated in a captured image of multi-slice CT.

  When a medical image including noise that does not exist in such a natural image is compressed by a conventional compression method, the compression efficiency is lower than that of a natural image, and it is difficult to achieve high compression.

  Natural images have high continuity of pixel values when viewed locally. The problem described above is caused by the premise of the feature of this natural image. When DWT is applied to a natural image, the distribution of values tends to be biased toward low frequency components in the frequency space in the converted data, and the compression rate increases as the tendency increases. However, since a medical image including noise includes more high frequency components than a natural image, the deviation in the frequency space is smaller than that of the natural image, and as a result, the compression rate is lowered.

  In addition, since medical images need to be compressed and stored losslessly without image quality degradation as described above, it is impossible to apply processing with image quality degradation such as quantizing frequency components to reduce the amount of information. This is a factor that makes high compression difficult.

  As described above, against the background of the rapid increase in the number of multi-slice images, that is, the amount of image data due to advances in diagnostic imaging apparatuses, there has been a demand for highly lossless multi-slice images. Furthermore, it is necessary to manage a highly compressed multi-slice image with ease for handling such as restoration and display.

  The present invention has been made to solve the above-described problems, and provides an image management apparatus, an image management program, and an image management method capable of efficiently managing compressed data of a plurality of images. Objective.

  In order to solve the above-described problem, an aspect of the present invention is an image management apparatus that manages compressed data obtained by compressing an image of a frame to which a frame number is assigned. An instruction acquisition unit that acquires a processing instruction for a frame, and a plurality of compression units composed of a plurality of consecutive frames are continuous, and the compression data of the first frame in each compression unit is compressed based on an image of only the first frame. For the compressed data obtained by compressing compressed data of frames other than the first frame in each compression unit based on the image of the immediately preceding frame, the instruction acquired by the instruction acquisition unit is the first A first frame of a first compression unit that is a frame deletion and the first frame is a compression unit to which the first frame belongs, or If it is not the final frame, the first frame image is restored based on the compressed data of the first frame, and the first frame is restored based on the first frame image and the compressed data of the next frame of the first frame. A restoration unit that restores the next frame image, a compression unit that compresses the next frame image restored by the restoration unit as compressed data of the first frame, and management information that manages the compressed data On the other hand, a first front compression unit constituted by a frame before the first frame in the first compression unit and a first one constituted by a frame after the first frame among the first compression units. The management information is changed to divide the first compression unit into a rear compression unit, and the compressed data of the next frame of the first frame is converted into the first rear compression unit. And a said management information changing unit for changing the management information so that the position of the first frame.

  Another aspect of the present invention is an image management program for causing a computer to perform management for managing compressed data obtained by compressing an image of a frame with a frame number. Compressed data obtained by acquiring a processing instruction for a frame, a plurality of continuous compression units composed of a plurality of consecutive frames, and compressed data of the first frame in each compression unit based on an image of only the first frame And for the compressed data obtained by compressing the compressed data of the frames other than the first frame in each compression unit based on the image of the immediately preceding frame, the instruction is deletion of the first frame, and the first frame Is not the first frame or the last frame of the first compression unit to which the first frame belongs, The image of the first frame is restored based on the compressed data of the first frame, and the image of the next frame of the first frame is restored based on the image of the first frame and the compressed data of the next frame of the first frame. The image of the next frame of the restored first frame is compressed as the compressed data of the first frame, and the management information for managing the compressed data is prior to the first frame in the first compression unit. The first compression unit is divided into a first front compression unit composed of a plurality of frames and a first rear compression unit composed of a frame after the first frame among the first compression units. The management information is changed and the management information is changed so that the compressed data of the next frame of the first frame becomes the first frame of the first rear compression unit. To be executed by the Yuta.

  According to another aspect of the present invention, there is provided an image management method for managing compressed data obtained by compressing an image of a frame with a frame number, the frame number of a specified frame and processing for the frame Are compressed data obtained by compressing the compressed data of the first frame in each compression unit based on the image of only the first frame, For compressed data in which compressed data of frames other than the first frame in each compression unit is compressed based on the image of the immediately preceding frame, the instruction is deletion of the first frame, and the first frame is the first frame. When it is not the first frame or the last frame of the first compression unit that is the compression unit to which one frame belongs, the compressed data of the first frame The first frame image is restored based on the first frame image, and the next frame image of the first frame is restored based on the first frame image and the compressed data of the next frame of the first frame. The image of the next frame of the first frame is compressed as the compressed data of the first frame, and the management information for managing the compressed data is the first of the first compression units composed of the frames before the first frame. Changing the management information so as to divide the first compression unit into one front compression unit and a first rear compression unit composed of a frame after the first frame among the first compression units; The management information is changed so that the compressed data of the next frame of the first frame becomes the first frame of the first rear compression unit.

  According to the present invention, it is possible to efficiently manage compressed data of a plurality of images.

  First, the prerequisite technology of the embodiment will be described with reference to the drawings.

(Prerequisite technology)
A feature of the image compression apparatus according to the base technology is that a multi-slice image composed of a plurality of frames is divided into groups each having a predetermined number of frames, each frame is further divided into blocks, and the block vertical size × block horizontal size × The pixel value of the pixel of interest is predicted so as to minimize the total entropy of the prediction error of each pixel in the compression unit using the pixel included in the number of frames in the group as the compression unit.

  In addition, this image compression apparatus applies the same prediction to the same block position in a plurality of frames, so that regularity of local change in noise included in the multi-slice image and continuity of pixel values between frames Prediction reflecting the similarity can be performed. As a result, the prediction accuracy can be improved and the value of the prediction error can be concentrated in the vicinity of 0 to improve the entropy coding efficiency.

  In CT, an X-ray generation source disposed opposite to the periphery of the human body and a detector for measuring the amount of X-ray are spirally rotated, and the X-ray of the human body cross section is determined from the amount of X-ray transmission detected by the detector. The difference in absorption amount is imaged as a luminance value. Here, since CT performs imaging while rotating, the imaging area in the obtained image is inside a circular area inscribed in the image. Since the outside of the circular area is outside the imaging area, a uniform value (for example, 0) is stored.

  In a multi-slice image, since the above-described shooting region is usually the same over all frames, this image compression apparatus detects a region where the same pixel value is continuous over a plurality of frames and detects the region from the compression target pixel. In addition to the exclusion, by separately outputting information indicating the region, it is possible to reduce the compression target pixels and increase the compression efficiency.

  In addition, this image compression apparatus improves prediction accuracy by selecting from among neighboring pixels having a high correlation with the target pixel as a reference pixel used for prediction of the pixel value of the target pixel. At this time, since the position of the reference pixel needs to be able to be referred to at the time of restoration, it is necessary to select from the compressed (restored at the time of restoration) pixel. This image compression apparatus performs compression according to the raster scan order. When performing, it selects from the pixels which exist before a pixel of interest in a raster scan order.

  In addition, this image compression apparatus sets a weight for the pixel value of each reference pixel, and calculates the predicted value of the pixel of interest by adding the values obtained by multiplying the pixel values of neighboring pixels by the weight. Further, this image compression apparatus uses one set of weights for each compression unit described above, and determines the weights so that a prediction error that is a difference between each pixel of interest in the compression unit and a prediction value is minimized. Thereby, optimal prediction can be performed for each region reflecting the continuity and similarity of local images and the continuity and similarity of pixel values between frames, and the compression rate can be improved.

  In addition, in the multi-slice image, the image of the frame including the pixel of interest has similarity and pixel value continuity with the image of the previous frame, so the pixels closer to the same position as the pixel of interest in the previous frame, It can be expected that the correlation with the pixel of interest is high. Therefore, this image compression apparatus can be expected to improve prediction accuracy by using the pixels of the previous frame in addition to the reference pixels for prediction. The position of the reference pixel of the previous frame can be selected at any position because the previous frame is compressed / restored before the frame including the target pixel, but is in the vicinity of the same position as the target pixel. The pixels are selected in descending order of correlation with the pixel of interest.

  In the compressed data, it is necessary to store the weight value of the reference pixel in addition to the encoded data obtained by entropy encoding the prediction error. This image compression apparatus assigns a predetermined number of bits to represent the weight value. . Therefore, the number of bits assigned to the weight is multiplied by the number of weights (= the number of reference pixels) and the total size of the compressed data when the prediction error is entropy-coded is minimized. By determining the number, the number of reference pixels can be determined so as to obtain the highest compression efficiency.

  In addition, since a pixel closer to the target pixel has a higher correlation with the target pixel and is suitable for use in prediction, the image compression apparatus uses a pixel in a position close to the target pixel for prediction. The prediction accuracy can be improved by selecting the pixel.

  Next, the configuration of the image compression apparatus according to the base technology will be described.

  FIG. 1 is a block diagram showing an example of the configuration of the image compression apparatus according to the base technology. This image compression apparatus uses a compression control unit 11, an intraframe coding unit 21, an interframe coding unit 22, and a compressed data for compression processing for generating compressed data from a multi-slice image (three-dimensional image). A restoration control unit 31, an intra-frame decoding unit 41, and an inter-frame decoding unit 42 are provided for the restoration process for generating the original multi-slice image.

  Next, the operation of the compression processing by the image compression apparatus according to the base technology will be described.

  First, the compression control unit 11 determines a compression condition in advance by performing a compression condition determination process for determining a compression condition that minimizes the size of the compressed data, and performs the compression process using the compression condition. . Details of the compression condition determination processing will be described later.

  FIG. 2 is a block diagram showing an example of the operation of the compression processing by the image compression apparatus according to the base technology. The compression control unit 11 acquires image information and region information from the input multi-slice image, and outputs the acquired information to compressed data. In addition, the compression control unit 11 divides the frame of the multi-slice image for each group, outputs the first frame of the group to the intraframe encoding unit 21, and outputs the group to the interframe encoding unit 22. The intra-frame coding unit 21 performs intra-frame prediction and entropy coding for each block in the head frame as intra-frame coding processing, and outputs the result to the compressed data as an intra-frame weight coefficient and intra-frame coded data. . The inter-frame coding unit 22 performs inter-frame prediction and entropy coding for each block in the frame in the group as inter-frame coding processing, and the result is compressed data as an inter-frame weight coefficient and inter-frame coded data. Output to.

  FIG. 3 is a flowchart showing an example of the operation of the compression process performed by the image compression apparatus according to the base technology. First, the compression control unit 11 includes the vertical and horizontal sizes (number of pixels) of each frame in the input multi-slice image, the total number of frames M, the number of frames in a group N, and the block size in a frame (number of blocks vertical pixels × block width). Information on the number of pixels (K × K) is output to the compressed data as image information (S101). Image information is required at the time of restoration. Here, the vertical and horizontal blocks have the same number of pixels, but different numbers of pixels may be used.

  Next, the compression control unit 11 detects an area having the same pixel value over all M frames of the input multi-slice image. Here, in the case of a CT image, the outside of a circular area that is a normal imaging area is detected. Next, the compression control unit 11 sets the pixels in the detected region as non-compression target regions that are regions that are not encoded, and sets other regions as compression target regions that are regions where encoding is performed ( S102). Here, the non-compression target area may be determined for each group as an area having the same pixel value over all N frames in the group.

  Next, the compression control unit 11 outputs the area information detected in the process S102 to the compressed data (S103). Here, the compression control unit 11 compresses the area information as much as possible. For example, if the shape of the compression target region is circular, the compression control unit 11 outputs the center position of the circle and the number of pixels of the radius to the compressed data, and if the shape of the compression target region is rectangular, the position of the upper left corner of the rectangle The number of vertical and horizontal pixels is output as compressed data. In addition, if the shape of the compression target region is an arbitrary shape, the compression control unit 11 can express the inside of the region as 0 and the outside of the region as 1, and can encode the continuous length of 0 and 1 by run-length encoding.

  Next, the compression control unit 11 sets the position where the compression process is started to the first frame (frame number i = 1) (S104).

  The next processes S105 to S108 are intraframe encoding processes by the intraframe encoder 21.

  First, the compression control unit 11 acquires N frames starting from the frame i from among the M frames and sets them as a target group. Of these, the intra-frame encoding unit 21 selects the frame i as the target frame (S105).

  Next, the intraframe coding unit 21 determines the weighting factor of the reference pixel so that the difference between the target pixel and the prediction error is minimized for each block in the target frame (S106). Here, the intra-frame coding unit 21 selects a block in the compression target region as a target block, selects a target pixel from the pixels in the target block according to the raster scan order, and weights the reference pixel for each target block. Determine the coefficient. FIG. 4 is a diagram illustrating an example of a raster scan order according to the base technology. The pixels in the block are selected from left to right for each line from the uppermost line to the lowermost line, and set as the target pixel.

  FIG. 5 is a diagram illustrating an example of selection of reference pixels in the intraframe coding processing according to the base technology. When a scanning number is assigned to each pixel in accordance with the scanning order, a predetermined number of pixels are selected as reference pixels from among pixels having a scanning number smaller than that of the pixel of interest in the compression target region and having a distance close to the pixel of interest. Is done. Here, the pixel value of the target pixel is X, the number of reference pixels is R, and the pixel values of R reference pixels for the target pixel are X1 to XR. In this figure, R = 6.

  Further, as an example of a method for determining a weighting factor, there are a method using a multiple regression analysis or a least square method. Here, the predicted value of the target pixel is P, the weighting coefficient of the reference pixel is W1 to WR, the prediction error is E, the evaluation value of the prediction error is e, the number of pixels in the block is F (F = K × K), Assuming that F pixel values in the block are X1 to XF and the constant term of the predicted value is C, the relationship between the parameters can be expressed by the equations shown in FIGS. FIG. 6 is an equation showing an example of a prediction value calculation formula in the intraframe coding processing according to the base technology. FIG. 7 is an equation showing an example of a prediction error calculation formula in the intraframe coding processing according to the base technology. FIG. 8 is an expression showing an example of an error evaluation value calculation expression in the intraframe coding processing according to the base technology.

  Here, the intra-frame coding unit 21 obtains an evaluation value e of the prediction error using the F pixels in each block of the target frame and the formula of FIG. 8, and weighting factors W1 to W1 are set so that e is minimized. WR and constant term C are obtained. The constant term C may be 0 in order to reduce the parameters necessary for prediction. Next, the intraframe encoding unit 21 outputs the determined weighting factors W1 to WR to the compressed data as intraframe weighting factors. Here, the bit accuracy for expressing the weighting factor is determined in advance so that the calculation error when calculating the predicted value is within a predetermined range.

  Next, the intra-frame encoding unit 21 sequentially sets each pixel in the target frame as a target pixel, calculates a predicted value from the weighting coefficient obtained in step S106 and the value of the reference pixel, using the formula in FIG. A prediction error with the target pixel is calculated from the equation (S107). Next, the intra-frame encoding unit 21 obtains a block including the target pixel as the target block from the position of the target pixel for which the prediction value is calculated, and selects a weighting factor (determined in step S106) corresponding to the target block.

  Next, the intraframe coding unit 21 entropy codes the prediction error of the target frame calculated in the process S107 (S108). Since the distribution of prediction error values is concentrated in the vicinity of 0, the GolombRice code is suitable as the entropy encoding method. Here, other methods such as Huffman coding and arithmetic coding may be applied. Next, the intraframe encoding unit 21 outputs the result of entropy encoding to the compressed data as intraframe encoded data.

  The next processes S109 to S112 are interframe encoding processes performed by the interframe encoder 22.

  First, the interframe coding unit 22 selects frames i + 1 to i + N excluding the frame i from the target group as a target frame group (S109). If the number of frames that have not been encoded is less than N, all the remaining frames are selected as the target frame group.

  Next, the interframe coding unit 22 determines the weighting factor of the reference pixel for each block in the target frame group (S110). The method of obtaining the weighting coefficient is the same as in the intra-frame coding process, but the point of interest is selected in the same target block in each frame in the target frame group, and the frame where the target pixel exists is set as the target frame. When the frame number is j, the reference pixel is selected from the pixels in a predetermined range in the frame of interest (j) and the immediately preceding frame (j−1), and the prediction error evaluation value e is obtained. The difference is that the pixels used extend over N frames, which are target groups. The pixel of interest is selected according to the raster scan order in the same block of interest in each frame in the target frame group.

  FIG. 9 is a diagram showing an example of reference pixel selection in the interframe coding processing according to the base technology. As a reference pixel, a predetermined number of pixels are selected from among pixels having a scanning number smaller than that of the pixel of interest and having a short distance from the pixel of interest. Further, a pixel at the same position as the pixel of interest in the previous frame and a neighboring pixel are selected. Is selected. Here, as in the intra-frame coding process, the pixel value of the target pixel is X, the number of reference pixels is S, and the pixel values of S reference pixels for the target pixel are X1 to XS. In this figure, S = 11. This figure also shows the position of the reference pixel in the current frame (j) where the pixel of interest exists and the previous frame (j-1).

  Here, the predicted value of the target pixel is P, the weighting coefficient of the reference pixel is W1 to WS, the prediction error is E, the evaluation value of the prediction error is e, and the number of pixels in the compression unit is G (G = K × K × N) When the G pixel values in the compression unit are X1 to XG and the constant term of the predicted value is C, the relationship between the parameters can be expressed by the equations shown in FIGS. FIG. 10 is an equation showing an example of a prediction value calculation equation in the interframe coding processing according to the base technology. FIG. 11 is an equation showing an example of a prediction error calculation formula in the interframe coding processing according to the base technology. FIG. 12 is an expression showing an example of an error evaluation value calculation expression in the interframe coding processing according to the base technology.

  Here, the inter-frame coding unit 22 obtains an evaluation value e of the prediction error using G pixels in each compression unit of the target frame and the equation of FIG. 12, and the weighting factor W1 so that e is minimized. ~ WS and constant term C are obtained. The constant term C may be 0 in order to reduce the parameters necessary for prediction. Next, the interframe encoding unit 22 outputs the determined weighting factors W1 to WS to the compressed data as interframe weighting factors.

  Next, the interframe coding unit 22 calculates a predicted value for each pixel of the target frame group from the weighting coefficient obtained in step S110 and the value of the reference pixel using the formula of FIG. 10, and the target pixel using the formula of FIG. (S111). The pixel of interest is scanned in the raster scan order as in the intra-frame encoding process. Next, the inter-frame encoding unit 22 obtains a block including the target pixel as the target block from the position of the target pixel for calculating the prediction value, and calculates the weighting coefficient of the reference pixel corresponding to the target block (determined in step S110). select.

  Next, the interframe coding unit 22 entropy codes the prediction error of the target frame group calculated in the process S111 (S112). As the entropy coding method, the GolombRice code is suitable as in the intra-frame coding process, but other methods such as Huffman coding and arithmetic coding may be applied. Next, the interframe encoding unit 22 outputs the result of entropy encoding as compressed interframe data as compressed data.

  The above-described intraframe encoding process and interframe encoding process are performed for each target group. Furthermore, since intra-frame coding processing and inter-frame coding processing are performed for each compression unit, which is a three-dimensional area obtained by dividing the target group into blocks, the correlation between pixel values within the compression unit is high, and compression efficiency Is expensive.

  Next, when all the M frames have been encoded (S113, Y), the compression control unit 11 ends the compression process, and when there are still unencoded frames (S113, N), The process proceeds to process S114.

  Next, the compression controller 11 adds N to the variable i representing the frame number in order to select the head of the frame to be encoded next (S114), and proceeds to processing S105.

  According to the above-described flow, the processing of S105 to S114 is repeatedly performed until the compression processing of all frames is completed, whereby the input M-frame multi-slice medical image is compressed.

  FIG. 13 is a diagram illustrating an example of a configuration of compressed data according to the base technology. This figure shows the compressed data output upon completion of compression. The compressed data includes the above-described image information and area information, the intra-frame weight coefficient and intra-frame encoded data obtained by the intra-frame encoding process, and the inter-frame weight coefficient and frame obtained by the inter-frame encoding process. Intercode data is stored. The intra-frame weight coefficient, intra-frame encoded data, inter-frame weight coefficient, and inter-frame code data are stored for each group.

  The intraframe coding process of the base technology uses the same method as the interframe coding process, but other lossless compression processes for two-dimensional images may be used.

  In the base technology, compression processing is performed according to the frame number, and in the inter-frame coding processing, reference pixels are selected from the current frame and the previous frame. When the compression processing is performed in the forward direction and the reverse direction on the frame number, the reference pixel may be selected according to the direction. Further, the reference pixel may be selected not only from one adjacent frame but also from two or more frames depending on the degree of correlation between frames.

  Next, the compression condition determination process will be described.

  FIG. 14 is a flowchart showing an example of the operation of compression condition determination processing by the image compression apparatus according to the base technology. First, the compression control unit 11 selects the first compression condition from the compression conditions (S301). The compression condition is a combination of the following three parameters.

Parameter 1. Reference pixel number and position (used in steps S106 and S110)
Parameter 2. Block size in the frame (used in steps S106 and S110)
Parameter 3. Number of frames in group (used in process S101)

  Here, the compression control unit 11 selects a combination of parameter 1 and parameter 2 as the compression condition used for the intra-frame encoding process, and parameter 1, parameter 2 and parameter 3 as the compression condition used for the inter-frame encoding process. Select a combination. The compression control unit 11 obtains an optimum value by changing the value within a predetermined range for each parameter.

  For parameter 1, the compression control unit 11 obtains the optimum value of the number of reference pixels by adding reference pixels in order from the closest to the target pixel according to a predetermined order. For parameter 2, the compression control unit 11 obtains an optimum value of the block size by gradually increasing the block size from a small size. For parameter 3, the compression control unit 11 obtains an optimum value for the number of frames in the group by gradually increasing the number of frames in the group from a predetermined small number.

  Next, the compression control unit 11 performs a compression process using the compression condition selected in the process S301 on the evaluation image (S302). Next, the compression control unit 11 determines whether or not the size of the compressed data is the smallest among the compressed data sizes obtained by the compression processing using the previous compression conditions, and if it is the smallest (S303). , Y), the process proceeds to step S304. If not the minimum (S303, N), the process proceeds to process S305.

  Next, the compression control unit 11 holds the compression condition for which the compression process has been performed in the process S302 (S304). That is, the compression condition that minimizes the compressed data size among the previous compression conditions is held.

  Next, the compression control unit 11 determines whether or not the compression process has been completed using all the compression conditions. If the compression process has been completed (S305, Y), the process proceeds to step S306. (S305, N), the process returns to S301. In the process S301, the next compression condition is selected and the processes after the process S302 are repeated.

  Next, the compression control unit 11 outputs the compression condition that minimizes the compressed data size selected in steps S301 to S305 as the optimum compression condition (S306). Thereafter, this compression condition is used for the compression process.

  The compression condition obtained by the above-described compression condition determination process is the optimum condition for the evaluation image, but it can be expected that the compression condition is close to the optimum if the images are of the same type. When it is necessary to perform compression using an optimal compression condition for each input multi-slice image, a compression condition determination process may be executed for each input multi-slice image. At that time, in step S304, the compressed data is held, and in step S306, instead of outputting the compression condition, the compressed data held in step S304 is output, so that the input image is compressed under the optimum compression condition. Compressed data can be output.

  Next, the operation of the restoration process by the image compression apparatus according to the base technology will be described.

  FIG. 15 is a flowchart showing an example of the operation of the restoration process by the image compression apparatus according to the base technology. First, the restoration control unit 31 acquires information about the number of vertical and horizontal pixels, the total number of frames M, the number of divided frames N, and the block size K × K pixels of the input image from the image information of the compressed data (S201). Next, the restoration control unit 31 acquires the compression target area from the area information of the compressed data. If the area information is encoded, the area information is decoded (S202).

  The next processes S203 to S205 are intra-frame decoding processes by the intra-frame decoding unit 41.

  Next, as in the compression process, the intra-frame decoding unit 41 determines a target frame, and acquires intra-frame weight coefficients W1 to WR for each block from the compressed data (S203). As a weighting coefficient, one set of W1 to WR is stored for each block. Here, as in the specific example of the compression process, the reference pixel number R = 6.

  Next, the intra-frame decoding unit 41 decodes the prediction error of the entropy-coded target frame (S204).

  Next, the intra-frame decoding unit 41 scans the prediction error decoded in the process S204 in the raster scan order described above, and calculates the predicted value P using the weighting factor acquired in the process S203 by the equation of FIG. Then, it is added to the prediction error to restore the original pixel value (S205).

  The next processes S206 to S208 are interframe decoding processes by the interframe decoding unit 42.

  First, the inter-frame decoding unit 42 determines a target frame group and acquires inter-frame weight coefficients W1 to WS from the compressed data, as in the compression process. One set of weighting factors W1 to WS is stored for each block. Here, as in the specific example, the reference pixel number S = 11 (S206).

  Next, the interframe decoding unit 42 decodes the interframe encoded data and obtains entropy encoded prediction errors. Here, prediction errors for N-1 frames, which are target frame groups, are decoded (S207).

  Next, the inter-frame decoding unit 42 scans the prediction error of each target frame group decoded in the process S207 in the raster scan order described above, and uses the weighting factor acquired in the process S203 to predict using the formula of FIG. The value P is calculated and added to the prediction error to restore the original pixel value (S208).

  Next, the restoration control unit 31 ends this flow when the restoration process for all M frames is completed (S209, Y), and when there is a frame that has not been restored (S209, N). The process returns to S203. By repeatedly performing the processing from S203 to S209 until the decoding processing for all M frames is completed, the original multi-slice medical image of M frames is restored.

  Note that the image compression apparatus according to the base technology uses a multi-slice CT / MR image, which is a three-dimensional image in which two-dimensional images (xy plane) are arranged for each depth (z-axis direction), as a compression target. A three-dimensional image in which (xy coordinates) are arranged for each time (t coordinate) may be a compression target. That is, the effect of the present invention can be obtained when there is a correlation between frames in the vicinity of a certain frame in a frame group consisting of frames that are two-dimensional images.

  Further, the image compression apparatus may be configured by the compression control unit 11, the intraframe coding unit 21, and the interframe coding unit 22. In addition to the image compression apparatus, the image restoration apparatus may include a restoration control unit 31, an intra-frame decoding unit 41, and an inter-frame decoding unit 42.

  As described above, according to the compression processing and the decompression processing according to the base technology, a higher compression rate can be realized in compression of a three-dimensional image than a lossless compression method using a conventional three-dimensional DWT. In other words, the storage capacity for storing image data can be reduced as compared with the conventional lossless compression method, thereby contributing to the improvement of the number of stored images and the cost reduction of the storage device for storing images.

  In addition, the image compression apparatus according to the base technology can be easily applied to the image processing apparatus, and the performance of the image processing apparatus can be further improved. Here, the image processing apparatus includes, for example, an information processing apparatus such as a PC (Personal Computer) or a server that executes image processing software, an image diagnosis apparatus such as CT or MR, and a photographing apparatus such as a digital still camera or a digital video camera. Etc. may be included.

  The image compression method described above can be restored independently for each compression unit. However, for frames other than the first frame in the compression unit, the pixel values of the immediately preceding frame are used for prediction, so it is necessary to restore the frames in order from the first frame. Therefore, if an arbitrary frame is deleted, it may not be possible to restore the image of the next frame. When an arbitrary frame is moved to another frame position, the previous frame image necessary for restoring the next frame image cannot be referred to in the movement source frame and the movement destination frame, and the next frame cannot be restored.

  As described above, the compressed data compressed using the inter-frame correlation in units of a plurality of frames has a problem that an arbitrary frame cannot be simply deleted or moved.

  As one method for solving this problem, a method of restoring the image of the entire compression unit and recompressing the remaining frames excluding the image of the frame to be deleted or moved can be considered. However, since restoration and recompression are performed on the entire compression unit, there is a problem that the processing load increases. In particular, the compression processing that requires several times the processing load as compared with the restoration processing is performed as many times as the restoration processing, so that the increase in processing load is remarkably increased.

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment)
In the present embodiment, an image browsing system for browsing and managing frames of compressed data by the above-described image compression method will be described.

  First, the data structure of the compressed data according to the present embodiment will be described.

  One frame of compressed data is stored in one compressed data file. Each frame is assigned a frame number which is a serial number of all frames in all compression units, and a unique file name is assigned to each compressed data file. There is also a management file for managing the compressed data file. The management file stores a frame number and a corresponding compressed data file name.

  FIG. 16 is a block diagram showing an example of the data structure of the compressed data according to the present embodiment. Here, the size of the compression unit is N frames. That is, a compressed data file of N consecutive frames belongs to one compression unit. In addition, the frame numbers of the frames belonging to the compression unit in this example are k to k + N−1.

  The compressed data file holds information related to the frame as a header in addition to the compressed data in which the image of the frame is encoded. The header of the compressed data file of the first frame (frame k) in the compression unit includes the number of frames p, an intra-frame prediction coefficient, and additional information. Additional information is other information. The header of the compressed data file of the second frame (frame k + 1) in the compression unit includes the frame number p, the compression unit number q, the inter-frame prediction coefficient, and additional information. The header of the compressed data file of the third and subsequent frames in the compression unit (frames k + 2 to k + N−1) is composed of the frame number p, the compression unit number q, and additional information. In this embodiment, the inter-frame prediction coefficients after the second frame in the compression unit are the same, and only the compressed data file of the second frame has the inter-frame prediction coefficient. The inter-frame prediction coefficient acquired in the second frame is used.

  By referring to the header, the first frame number and the last frame number of the compression unit including the arbitrary frame can be acquired. The image browsing system according to the present embodiment performs control with reference to this header.

  If the number of frames in the header of the compressed data file is not 0, the frame is the first frame. The compressed data of the first frame is intra-frame encoded data. On the other hand, when the number of frames in the header of the compressed data file is 0, the frame is other than the first frame, and a compression unit number that is a number from the first frame is added. The compressed data other than the first frame is inter-frame encoded data.

  In the present embodiment, the header of the first frame of each compression unit includes the number N of frames included in the compression unit and an intra-frame prediction coefficient for the first frame. In addition, the header of the frame other than the head includes identification information (0) indicating that it is not the head frame, and an image number (1 to N-1) indicating the number of the frame within the compression unit. The header of the second frame of each compression unit includes the inter-frame prediction coefficient of the second and subsequent frames. Since this inter-frame prediction coefficient is the same in frames other than the head, this inter-frame prediction coefficient is omitted in the headers of the third and subsequent frames of the compression unit.

  Next, the configuration of the image browsing system according to the present embodiment will be described.

  FIG. 17 is a block diagram showing an example of the configuration of the image browsing system according to the present embodiment. This image browsing system includes a server device 111 and a client device 212. The server device 111 and the client device 212 are connected via a network. The server device 111 includes a compressed data storage unit 121. The client device 212 includes an instruction unit 231, a display unit 232, an image management device 233, and an input unit 234. The image management apparatus 233 includes a management control unit 241 (instruction acquisition unit), a compression information change unit 242 (management information change unit), a compressed data acquisition unit 243, a compressed data holding unit 244, a restoration unit 245, an image holding unit 246, a compression Part 247 is provided.

  A frame deletion instruction, a frame insertion instruction, and a frame movement instruction are input to the management control unit 241. The management control unit 241 controls acquisition, restoration, compression, and change of compressed information of compressed data.

  The compressed data acquisition unit 243 acquires the compressed data of the compression unit including the frames to be deleted and the frames before and after the movement from the compressed data storage unit 121 and stores them in the compressed data holding unit 243.

  The restoration unit 245 restores the compressed data stored in the compressed data holding unit 244 based on an instruction from the management control unit 241, generates a restored image, and stores the restored image in the image holding unit 246.

  The compression unit 247 compresses the restored image stored in the image holding unit 246 based on an instruction from the control unit, and stores the compressed data in the compressed data holding unit 244.

  The compression information changing unit 242 changes compression information (management information) such as a header of a compressed data file and a management file stored in the compressed data holding unit 244 based on an instruction from the management control unit 241.

  The compressed data holding unit 244 replaces old compressed data stored in the compressed data storage unit 121 with new compressed data held in the compressed data holding unit 244 based on an instruction from the management control unit 241.

  In addition, the compressed data holding unit 244 reflects the change to the compressed data file in the management file.

  Next, operations of frame deletion processing, frame insertion processing, and frame movement processing by the image management apparatus 233 according to the present embodiment will be described.

  FIG. 18 is a conceptual diagram showing an example of frame deletion processing by the image management apparatus according to the present embodiment. FIG. 19 is a conceptual diagram showing an example of frame insertion processing by the image management apparatus according to the present embodiment. FIG. 20 is a conceptual diagram showing an example of frame movement processing by the image management apparatus according to the present embodiment. In these drawings, the vertically long rectangles are each frame, and are arranged from left to right in the order of frame numbers.

  The frame deletion process is a process of deleting the frame f0 according to the frame deletion instruction. However, if the frame f0 is simply deleted, there arises a problem that the frame next to the frame f0 cannot be restored. The frame insertion process is a process of inserting a new frame at the position of the frame f1 in accordance with the frame insertion instruction. However, if the frame f0 is simply deleted, there arises a problem that the frame next to the inserted frame cannot be restored. The frame movement process is a process of moving the frame f0 to the position of the frame f1 according to the frame movement instruction. However, simply deleting the frame f0 causes a problem such that the next frame of the frame f0 cannot be restored, and simply deleting the frame f0 causes a problem such that the next frame of the moved frame cannot be restored. .

  The image management apparatus 233 of the present embodiment pays attention to the fact that only the immediately following frame is affected by the frame deletion, insertion, and movement, and deletion and insertion of an arbitrary frame by the minimum necessary restoration and compression. Realize the move.

  First, the operation of frame deletion processing by the image management apparatus 233 according to the present embodiment will be described.

  FIG. 21 is a flowchart showing an example of the operation of frame deletion processing by the image management apparatus according to the present embodiment. The frame deletion process in this example is a process for deleting the frame f0.

S501: The compressed data acquisition unit 243 refers to the management file stored in the compressed data storage unit 121 to detect a compression unit including the frame f0 instructed by the frame deletion instruction from the outside (instruction unit 231). The first frame number s0 and the last frame number e0 of the compression unit are acquired. Specifically, the compressed data acquisition unit 243 acquires the header of the frame f0 from the compressed data storage unit 121, and the header value p is other than 0 (when the number of frames of the first frame is stored). , Frame f is the first frame, that is, s0 = f0, and e0 = f0 + p is the final frame number. On the other hand, when p is 0 (when it is a frame other than the head), the compressed data acquisition unit 243 acquires the next value q (in-compression unit number), and sets s0 = f0−q as the head frame number. To do. Next, the compressed data acquisition unit 243 acquires the header of the frame f-q, obtains the header header value p, and sets e0 = f0 + p-q as the final frame number.

S502: If the frame f0 is the last frame, the management control unit 241 moves the process to S510, and if the frame f0 is not the last frame, the management control unit 241 advances the process to S503.

S503: The restoration unit 245 restores the first frame s0 to the frame f0 + 1, that is, the frame next to the frame f0.

S504: If the frame f0 is a frame immediately before the final frame, the management control unit 241 moves the process to S508, and if the frame f0 is a frame before the final frame, the management control unit 241 advances the process to S507.

S505: The compression information changing unit 242 inserts the prediction coefficient included in the header of the frame s0 + 1 into the header of the compressed data of the frame f0 + 2.

S506: The compression information changing unit 242 changes the image numbers included in the headers of the compressed data from the frame f0 + 2 to the frame e0 from 1 to e0-f0, respectively.

S507: The compression unit 247 performs intra-frame prediction on the restored image of the frame f0 + 1 and performs two-dimensional compression (generates compressed data that does not depend on other frames).

S508: The compression information changing unit 242 stores the number of frames of the compressed data of the frame f0 + 1 compressed in S507 as e0-f0, that is, the number of frames after f in the compression unit. This is because the frame f0 + 1 becomes the first frame of the rear compression unit among the two compression units obtained by dividing the frame f0. By the processing so far, the frame after the frame f0, that is, the frame f0 + 1 to the frame e0 becomes one compression unit, and this compression unit can be restored as usual.

S509: If the frame f0 is the first frame, the management control unit 241 moves the process to S511. If the frame f0 is not the first frame, the management control unit 241 advances the process to S510.

S510: The compression information changing unit 242 changes the number of frames p included in the compressed data header of the frame s0 to f0. By the processing so far, the frame ahead of the frame f0, that is, the frame s0 to the frame f0-1, becomes one compression unit, and this compression unit can be restored as usual.

S511: The compressed data holding unit 244 deletes the compressed data of the frame f0 and completes the deletion process.

  Next, a specific example of the frame deletion process according to the present embodiment will be described.

  FIG. 22 is a conceptual diagram showing a first case in the frame deletion processing according to the present embodiment. FIG. 23 is a conceptual diagram showing a second case in the frame deletion processing according to the present embodiment. FIG. 24 is a conceptual diagram showing a third case in the frame deletion processing according to the present embodiment. In this example, the original compression unit size is set to 8 frames in consideration of the balance between the compression and decompression speed and the compression rate.

  These figures show the state of each frame in the compression unit to which the frame instructed by the frame deletion instruction belongs. A vertically long rectangle indicates each frame and is arranged in order of frame number from left to right. Further, step numbers (S501 to S511) in the drawings of the first case to the third case correspond to the step numbers in the flowchart of the frame deletion process described above. Further, characters (s0, f0, e0, etc.) written at the bottom of each frame in the drawings of the first case to the third case indicate the frame number of that frame.

  The first case shows the operation when the first frame of the compression unit is deleted. The second case shows the operation when the last frame of the compression unit is deleted. The third case shows the operation when deleting frames other than the first frame and the last frame.

  The method of recompressing after restoring the entire compression unit and deleting the frame image requires restoration of 8 frames and compression of 7 frames. On the other hand, in the first case according to the present embodiment, restoration for two frames and compression for one frame are sufficient. In the second case according to the present embodiment, the restoration for 0 frame and the compression for 0 frame are sufficient. Further, in the third case according to the present embodiment, restoration for 5 frames and compression for 1 frame are sufficient.

  In the third case, the necessary number of restorations varies from 3 to 8 depending on the position of the frame to be deleted. Assuming that all the positions of frames to be deleted within the compression unit have the same probability, the average number of restored frames and the average number of compressed frames per frame are about 4.4 frames and about 0.88 frames, respectively. It becomes.

  According to the frame deletion processing according to the present embodiment, compared with a method for restoring and compressing the entire compression unit, compression processing having a larger processing load than restoration can be significantly reduced, which contributes to reduction of the processing load.

  Next, an operation of frame insertion processing by the image management apparatus 233 according to this embodiment will be described.

  FIG. 25 is a flowchart showing an example of the operation of frame insertion processing by the image management apparatus according to the present embodiment. The frame insertion process in this example is a process for inserting a new frame at the position of the frame f1.

S611: The compressed data acquisition unit 243 refers to the management file stored in the compressed data storage unit 121, and includes a compression unit including the insertion-destination frame f1 instructed by the frame insertion instruction from the outside (instruction unit 231). And the first frame number s1 and the last frame number e1 of the compression unit are obtained.

S612: The management control unit 241 proceeds to S619 when the frame f1 is the first frame or the last frame, and proceeds to S613 when the frame f1 is not the first frame. That is, when the destination frame position is the boundary of the compression unit, it is not necessary to restore the data of the compression unit, so the processing from S613 to S619 is skipped.

S613: The restoration unit 245 restores the first frame s1 to the frame f1.

S614: If the frame f1 is a frame immediately before the final frame, the management control unit 241 moves the process to S616, and if the frame f1 is a frame before the final frame, the management control unit 241 advances the process to S615.

S615: The compression information changing unit 242 inserts the prediction coefficient included in the header of the frame s1 + 1 into the header of the compressed data of the frame f1 + 1.

S616: The compression information changing unit 242 changes the image numbers included in the headers of the compressed data from the frame f1 + 1 to the frame e1 from 1 to e1-f1, respectively.

S617: The restoration unit 245 performs intra-frame prediction on the restored image of the frame f1 to perform two-dimensional compression (generates compressed data that does not depend on other frames).

S618: The compression information changing unit 242 sets the value of the number of frames p in the header of the frame f1 compressed in S617 to ef + 1. That is, the value of p is the number of frames after the frame f1 in the compression unit. This is because the first frame of the rear compression unit among the compression units divided into two by the insertion of the frame f1 is used. By the processing so far, the frames after the frame f1, that is, the frames f1 to e1 become one compression unit, and restoration can be performed as usual.

S619: The compression information changing unit 242 changes the number of frames included in the compressed data header of the frame s1 to f1. By this processing, the frame ahead of the frame f1, that is, the frame s1 to the frame f1-1 becomes one compression unit, and the restoration can be performed as usual.

S620: The compression information changing unit 242 increments the frame number included in the header of the compressed data after the frame f1, and ends the frame insertion process.

  According to the frame moving process according to the present embodiment, compared with a method of restoring and compressing the entire compression unit, the compression process having a larger processing load than the restoration can be significantly reduced, which contributes to the reduction of the processing load.

  Next, the operation of frame movement processing by the image management apparatus 233 according to this embodiment will be described.

  FIG. 26 is a flowchart showing an example of the operation of frame movement processing by the image management apparatus according to the present embodiment. The frame movement process in this example is a process of moving the image of the frame f0 to the position of the frame f1, that is, a process of deleting the image of the frame f0 and inserting it to the position of the frame f1.

  S501 to S511 in the frame movement process are the same as the frame deletion process, but S507a is executed instead of S507, and S511a is executed instead of S511.

S507a: The compression unit 247 performs two-dimensional compression on the restored image of the source frame f0 and the restored image of the next frame f0 + 1 using intra prediction (generates compressed data independent of other frames).

S511a: The compression information changing unit 242 rewrites the header of the source frame f0 with the header of the destination frame f1.

  Further, S611 to S619 in the frame movement process are the same as the frame insertion process. S620a, S621a, and S622a are executed instead of S620.

S620a: When the movement source frame f0 is moved backward, that is, when f0 <f1, the management control unit 241 advances the process to S621a, and the management control unit 241 moves the movement source frame forward, that is, f1. If <f0, the process proceeds to S622a.

S621a (during backward movement): The frame number included in the header of the compressed data from frame f0 + 1 to frame f1-1 is reduced by 1, and the frame movement process is terminated. That is, when the frame f0 moves to the rear frame f1, the frame order from the frame f0 + 1 to the frame f1-1 is shifted forward by one frame.

S622a (during forward movement): The frame number included in the header of the compressed data from frame f1 to frame f0-1 is incremented by 1, and the frame movement process is terminated. That is, when the frame f0 moves to the front frame f1, the order of the frames from the frame f1 to the frame f0-1 is shifted backward by one frame.

  By the processing of S619 to S622a, the frame number after the frame movement is reflected in the compressed data of the frame included between the movement source frame and the movement destination frame.

  Next, a specific example of the frame movement process according to the present embodiment will be described.

  FIG. 27 is a conceptual diagram showing a first case in the frame movement processing according to the present embodiment. FIG. 28 is a conceptual diagram showing a second case in the frame movement processing according to the present embodiment. FIG. 29 is a conceptual diagram showing a third case in the frame movement processing according to the present embodiment. In this example, the original compression unit size is set to 8 frames in consideration of the balance between the compression and decompression speed and the compression rate.

  These figures show the movement source compression unit to which the movement source frame designated by the frame movement instruction belongs and the movement source compression unit to which the movement destination frame designated by the frame movement instruction belongs. Indicates the frame status. A vertically long rectangle indicates each frame and is arranged in order of frame number from left to right. Further, step numbers (S501 to S622a) in the drawings of the first case to the third case correspond to the step numbers in the flowchart of the frame movement process described above. Further, characters (s0, f0, e0, etc.) written at the bottom of each frame in the drawings of the first case to the third case indicate the frame number of that frame.

  The first case shows an example of processing (S611 to S619) for the destination compression unit in the frame movement processing. Since the processing for the source compression unit is the same as the frame deletion processing, description thereof is omitted. The second case and the third case show examples of the processing of S620a to S622a. The second case is an example when moving the frame backward (S621a), and the third case is an example when moving the frame forward (S622a).

  The method of recompressing after moving the frame image by restoring the entire compression unit of the movement source and the movement destination requires restoration of 12 frames and compression of 12 frames (when moving within a frame, Consider moving between). On the other hand, in the first case and the second case according to the present embodiment, restoration for 7 frames is sufficient for compression for 3 frames.

  Assuming that all the positions of the frames moved within the compression unit have the same probability, the average number of decompressed frames and the average number of compressed frames at the time of deletion per frame are about 8.2 frames and about 2.7 frames, respectively. It becomes.

  According to the frame moving process according to the present embodiment, compared with a method of restoring and compressing the entire compression unit, the compression process having a larger processing load than the restoration can be significantly reduced, which contributes to the reduction of the processing load.

  According to the frame deletion process, the frame insertion process, and the frame movement process according to the present embodiment, the deletion, insertion, and movement of an arbitrary frame of a 3D image compressed in units of a plurality of frames are realized with a minimum processing amount. can do. For this reason, in a system that performs handling such as decompression and display of three-dimensional compressed data, it is possible to improve the usability by increasing the response at the time of frame deletion, insertion, and movement.

  In addition, the image management apparatus according to the present embodiment can be easily applied to an image diagnostic apparatus, and can further improve the performance of the image diagnostic apparatus. Here, the diagnostic imaging apparatus can include, for example, CT, MR, and the like.

  Furthermore, it is possible to provide a program that causes a computer constituting the image management apparatus to execute the above steps as an image management program. By storing the above-described program in a computer-readable recording medium, the computer constituting the image management apparatus can be executed. Here, examples of the recording medium readable by the computer include an internal storage device such as a ROM and a RAM, a portable storage such as a CD-ROM, a flexible disk, a DVD disk, a magneto-optical disk, and an IC card. It includes a medium, a database holding a computer program, another computer and its database, and a transmission medium on a line.

  The present invention can be implemented in various other forms without departing from the spirit or main features thereof. Therefore, the above-described embodiment is merely an example in all respects and should not be interpreted in a limited manner. The scope of the present invention is shown by the scope of claims, and is not restricted by the text of the specification. Moreover, all modifications, various improvements, substitutions and modifications belonging to the equivalent scope of the claims are all within the scope of the present invention.

  Regarding the above embodiment, the following additional notes are disclosed.

(Supplementary Note 1) An image management apparatus that manages compressed data obtained by compressing a frame numbered image.
An instruction acquisition unit for acquiring a frame number of a specified frame and an instruction of processing for the frame;
A plurality of continuous compression units composed of a plurality of consecutive frames, and the compressed data of the first frame in each compression unit is compressed data based on the image of only the first frame, and the first frame in each compression unit For compressed data obtained by compressing compressed data of a frame other than that based on the image of the immediately preceding frame, the instruction acquired by the instruction acquiring unit is deletion of the first frame, and the first frame is the first frame If it is not the first frame or the last frame of the first compression unit that is the compression unit to which one frame belongs, the image of the first frame is restored based on the compressed data of the first frame, and the image of the first frame and the first frame are restored. A restoration unit for restoring an image of the next frame of the first frame based on compressed data of the next frame of one frame;
A compression unit that compresses an image of the next frame of the first frame restored by the restoration unit as compressed data of a first frame;
For management information for managing the compressed data, a first front compression unit composed of a frame before the first frame of the first compression unit and a first frame of the first compression unit. The management information is changed to divide the first compression unit into a first rear compression unit composed of a later frame, and the compressed data of the next frame of the first frame is changed to the first rear compression unit. The management information changing unit for changing the management information so as to be a first frame;
An image management apparatus comprising:
(Supplementary Note 2) In the image management apparatus according to Supplementary Note 1,
When the instruction acquired by the instruction acquisition unit is deletion of the first frame, and the first frame is the first frame of the first compression unit,
The restoration unit restores the image of the first frame based on the compressed data of the first frame, and the first frame based on the image of the first frame and the compressed data of the next frame of the first frame. Restore the image of the next frame of
The compression unit compresses the image of the next frame of the first frame restored by the restoration unit into compressed data of the first frame,
The management information changing unit changes the management information so that a frame after the first frame in the first compression unit constitutes a new first compression unit, and the management information change unit changes the management information of the next frame of the first frame. An image management apparatus that changes the management information so that compressed data is a first frame of the new first compression unit.
(Supplementary Note 3) In the image management apparatus according to Supplementary Note 1,
When the instruction acquired by the instruction acquisition unit is deletion of the first frame, and the first frame is the last frame of the first compression unit,
The restoration unit does not restore an image,
The compression unit does not compress the image,
The management information changing unit is an image management device that changes the management information so that a frame before the first frame in the first compression unit constitutes a new first compression unit.
(Supplementary Note 4) In the image management apparatus according to Supplementary Note 1,
When the instruction acquired by the instruction acquisition unit is the insertion of a new image at the position of the second frame, and the second frame is not the first frame of the second compression unit that is the compression unit to which the second frame belongs ,
The restoration unit restores the image of the second frame based on the compressed data of the second compression unit,
The compression unit compresses the new image as compressed data of the first frame, compresses the second frame image restored by the restoration unit as compressed data of the first frame,
The management information changing unit includes a second front compression unit configured by a frame before the second frame in the second compression unit and a frame after the second frame among the second compression units. Dividing the second compression unit into second rear compression units, and inserting a third compression unit as a new compression unit between the second front compression unit and the second rear compression unit. An image management device that changes the management information and changes the management information so that the compressed data of the new image is the first frame of the third compression unit.
(Supplementary Note 5) In the image management apparatus according to Supplementary Note 1,
When the instruction acquired by the instruction acquisition unit is insertion of a new image at the position of the second frame, and the second frame is the first frame of the second compression unit,
The restoration unit does not restore an image,
The compression unit compresses the new image as compressed data of the first frame,
The management information changing unit changes the management information so that a third compression unit, which is a new compression unit, is inserted before the second compression unit, and converts the compressed data of the new image into a new compression unit. An image management apparatus that changes the management information so as to be the first frame of the third compression unit.
(Supplementary Note 6) In the image management apparatus according to Supplementary Note 1,
When the instruction acquired by the instruction acquisition unit is the movement of the frame from the first frame to the position of the second frame,
The restoration unit, the compression unit, and the management information change unit are an image management apparatus that deletes the first frame and inserts the image of the first frame at the position of the second frame.
(Supplementary note 7) In the image management device according to supplementary note 6,
When the instruction acquired by the instruction acquisition unit is the movement of the frame from the first frame to the position of the second frame,
The management information changing unit changes the management information so as to move the first frame to the position of the second frame, and changes the first frame in the first compression unit to which the first frame belongs. The management information is changed so as to change the configuration of the first compression unit based on the position, and the second frame is based on the position of the second frame in the second compression unit that is the compression unit to which the second frame belongs. 2. An image management apparatus that changes the management information so as to change the configuration of a compression unit.
(Supplementary Note 8) In the image management apparatus according to Supplementary Note 1,
The management information changing unit is an image management device that changes the management information so that frame numbers are continuous after processing based on the instruction.
(Supplementary note 9) An image management program for causing a computer to perform management for managing compressed data obtained by compressing an image of a frame with a frame number,
Get the frame number of the specified frame and the processing instruction for that frame,
A plurality of continuous compression units composed of a plurality of consecutive frames, and the compressed data of the first frame in each compression unit is compressed data based on the image of only the first frame, and the first frame in each compression unit For compressed data in which compressed data of a frame other than the above is compressed based on the image of the immediately preceding frame, the instruction is deletion of the first frame, and the first frame is a compression unit to which the first frame belongs. If the first frame is not the first frame or the last frame, the first frame image is restored based on the compressed data of the first frame, and the first frame image and the next frame of the first frame are compressed. Restoring the image of the next frame of the first frame based on the data,
Compressing the restored image of the next frame of the first frame as compressed data of the first frame;
For management information for managing the compressed data, a first front compression unit composed of a frame before the first frame of the first compression unit and a first frame of the first compression unit. The management information is changed to divide the first compression unit into a first rear compression unit composed of a later frame, and the compressed data of the next frame of the first frame is changed to the first rear compression unit. An image management program for causing a computer to change the management information so as to be a first frame.
(Supplementary Note 10) In the image management program according to Supplementary Note 9,
When the instruction is deletion of the first frame and the first frame is the first frame of the first compression unit,
The image of the first frame is restored based on the compressed data of the first frame, and the image of the next frame of the first frame is restored based on the image of the first frame and the compressed data of the next frame of the first frame. Restore
The restored image of the next frame of the first frame is compressed as the compressed data of the first frame,
The management information is changed so that a frame after the first frame of the first compression unit constitutes a new first compression unit, and the compressed data of the next frame of the first frame is changed to the new first compression unit. An image management program for changing the management information so as to be a first frame of one compression unit.
(Appendix 11) In the image management program described in Appendix 9,
When the instruction is deletion of the first frame and the first frame is the last frame of the first compression unit,
Without restoring the image,
Without compressing the image,
An image management program for changing the management information so that a frame before the first frame in the first compression unit constitutes a new first compression unit.
(Supplementary note 12) In the image management program described in supplementary note 9,
When the instruction is insertion of a new image at the position of the second frame, and the second frame is not the first frame of the second compression unit that is the compression unit to which the second frame belongs,
Restoring the image of the second frame based on the compressed data of the second compression unit;
Compressing the new image as compressed data of the first frame and compressing the restored second frame image as compressed data of the first frame,
A second front compression unit composed of a frame before the second frame in the second compression unit, and a second rear compression unit composed of a frame after the second frame in the second compression unit; The management information is changed so that the second compression unit is divided and a third compression unit, which is a new compression unit, is inserted between the second front compression unit and the second rear compression unit. An image management program for changing the management information so that the compressed data of the new image is the first frame of the third compression unit.
(Supplementary note 13) In the image management program according to supplementary note 9,
When the instruction is the insertion of a new image at the position of the second frame, and the second frame is the first frame of the second compression unit,
Without restoring the image,
Compress the new image as the compressed data of the first frame,
The management information is changed so that a third compression unit, which is a new compression unit, is inserted before the second compression unit, and compressed data of the new image is changed to a third compression unit, which is a new compression unit. An image management program for changing the management information so as to be a first frame.
(Supplementary Note 14) In the image management program according to Supplementary Note 9,
If the indication is a movement of the frame from the first frame to the position of the second frame,
An image management program for deleting the first frame and inserting the image of the first frame at the position of the second frame.
(Supplementary Note 15) In the image management program according to Supplementary Note 14,
If the indication is a movement of the frame from the first frame to the position of the second frame,
The management information is changed to move the first frame to the position of the second frame, and the first frame is based on the position of the first frame in the first compression unit that is the compression unit to which the first frame belongs. The management information is changed to change the configuration of the compression unit, and the configuration of the second compression unit is changed based on the position of the second frame in the second compression unit to which the second frame belongs. An image management program for changing the management information as described above.
(Supplementary Note 16) An image management method for performing management for managing compressed data obtained by compressing a frame numbered image.
Get the frame number of the specified frame and the processing instruction for that frame,
A plurality of continuous compression units composed of a plurality of consecutive frames, and the compressed data of the first frame in each compression unit is compressed data based on the image of only the first frame, and the first frame in each compression unit For compressed data in which compressed data of a frame other than the above is compressed based on the image of the immediately preceding frame, the instruction is deletion of the first frame, and the first frame is a compression unit to which the first frame belongs. If the first frame is not the first frame or the last frame, the first frame image is restored based on the compressed data of the first frame, and the first frame image and the next frame of the first frame are compressed. Restoring the image of the next frame of the first frame based on the data,
Compressing the restored image of the next frame of the first frame as compressed data of the first frame;
For management information for managing the compressed data, a first front compression unit composed of a frame before the first frame of the first compression unit and a first frame of the first compression unit. The management information is changed to divide the first compression unit into a first rear compression unit composed of a later frame, and the compressed data of the next frame of the first frame is changed to the first rear compression unit. An image management method for executing the change of the management information so as to be a first frame.
(Supplementary note 17) In the image management method according to supplementary note 16,
When the instruction is deletion of the first frame and the first frame is the first frame of the first compression unit,
The image of the first frame is restored based on the compressed data of the first frame, and the image of the next frame of the first frame is restored based on the image of the first frame and the compressed data of the next frame of the first frame. Restore
The restored image of the next frame of the first frame is compressed as the compressed data of the first frame,
The management information is changed so that a frame after the first frame of the first compression unit constitutes a new first compression unit, and the compressed data of the next frame of the first frame is changed to the new first compression unit. An image management method for changing the management information so as to be a first frame of one compression unit.
(Supplementary note 18) In the image management method according to supplementary note 16,
When the instruction is deletion of the first frame and the first frame is the last frame of the first compression unit,
Without restoring the image,
Without compressing the image,
An image management method for changing the management information so that a frame before the first frame in the first compression unit constitutes a new first compression unit.
(Supplementary note 19) In the image management method according to supplementary note 16,
When the instruction is insertion of a new image at the position of the second frame, and the second frame is not the first frame of the second compression unit that is the compression unit to which the second frame belongs,
Restoring the image of the second frame based on the compressed data of the second compression unit;
Compressing the new image as compressed data of the first frame and compressing the restored second frame image as compressed data of the first frame,
A second front compression unit composed of a frame before the second frame in the second compression unit, and a second rear compression unit composed of a frame after the second frame in the second compression unit; The management information is changed so that the second compression unit is divided and a third compression unit, which is a new compression unit, is inserted between the second front compression unit and the second rear compression unit. An image management method for changing the management information so that the compressed data of the new image is the first frame of the third compression unit.
(Supplementary note 20) In the image management method according to supplementary note 16,
When the instruction is the insertion of a new image at the position of the second frame, and the second frame is the first frame of the second compression unit,
Without restoring the image,
Compress the new image as the compressed data of the first frame,
The management information is changed so that a third compression unit, which is a new compression unit, is inserted before the second compression unit, and compressed data of the new image is changed to a third compression unit, which is a new compression unit. The management information is changed to be the first frame, and the image management method.

It is a block diagram which shows an example of a structure of the image compression apparatus which concerns on a premise technique. It is a block diagram which shows an example of the operation | movement of the compression process by the image compression apparatus which concerns on a premise technique. It is a flowchart which shows an example of the operation | movement of the compression process by the image compression apparatus which concerns on a premise technique. It is a figure which shows an example of the raster scan order which concerns on a premise technique. It is a figure which shows an example of selection of the reference pixel in the intra-frame encoding process which concerns on a premise technique. It is a formula which shows an example of the calculation formula of the predicted value in the intraframe encoding process which concerns on a premise technique. It is a formula which shows an example of the calculation formula of the prediction error in the intra-frame encoding process which concerns on a premise technique. It is a formula which shows an example of the calculation formula of the error evaluation value in the intra-frame encoding process which concerns on a premise technique. It is a figure which shows an example of selection of the reference pixel in the interframe encoding process which concerns on a premise technique. It is a formula which shows an example of the calculation formula of the predicted value in the inter-frame encoding process which concerns on a premise technique. It is a formula which shows an example of the calculation formula of the prediction error in the inter-frame encoding process which concerns on a premise technique. It is a formula which shows an example of the calculation formula of the error evaluation value in the inter-frame encoding process which concerns on a premise technique. It is a figure which shows an example of a structure of the compressed data which concerns on a premise technique. It is a flowchart which shows an example of operation | movement of the compression condition determination process by the image compression apparatus which concerns on a premise technique. It is a flowchart which shows an example of the operation | movement of the decompression | restoration process by the image compression apparatus which concerns on a premise technique. It is a block diagram which shows an example of the data structure of the compressed data which concerns on this Embodiment. It is a block diagram which shows an example of a structure of the image browsing system which concerns on this Embodiment. It is a conceptual diagram which shows an example of the frame deletion process by the image management apparatus which concerns on this Embodiment. It is a conceptual diagram which shows an example of the frame insertion process by the image management apparatus which concerns on this Embodiment. It is a conceptual diagram which shows an example of the frame movement process by the image management apparatus which concerns on this Embodiment. It is a flowchart which shows an example of the operation | movement of the frame deletion process by the image management apparatus which concerns on this Embodiment. It is a conceptual diagram which shows the 1st case in the frame deletion process which concerns on this Embodiment. It is a conceptual diagram which shows the 2nd case in the frame deletion process which concerns on this Embodiment. It is a conceptual diagram which shows the 3rd case in the frame deletion process which concerns on this Embodiment. It is a flowchart which shows an example of the operation | movement of the frame insertion process by the image management apparatus which concerns on this Embodiment. It is a flowchart which shows an example of the operation | movement of the frame movement process by the image management apparatus which concerns on this Embodiment. It is a conceptual diagram which shows the 1st case in the frame movement process which concerns on this Embodiment. It is a conceptual diagram which shows the 2nd case in the frame movement process which concerns on this Embodiment. It is a conceptual diagram which shows the 3rd case in the frame movement process which concerns on this Embodiment.

Explanation of symbols

111 server devices, 212 client devices, 121 compressed data storage unit, 231 instruction unit, 232 display unit, 233 image management device, 234 input unit, 241 management control unit, 242 compression information change unit, 243 compressed data acquisition unit, 244 compression Data holding unit, 245 restoration unit, 246 image holding unit, 247 compression unit.

Claims (10)

An image management apparatus that manages compressed data obtained by compressing a frame numbered frame image,
An instruction acquisition unit for acquiring a frame number of a specified frame and an instruction of processing for the frame;
A plurality of continuous compression units composed of a plurality of consecutive frames, and the compressed data of the first frame in each compression unit is compressed data based on the image of only the first frame, and the first frame in each compression unit For compressed data obtained by compressing compressed data of a frame other than that based on the image of the immediately preceding frame, the instruction acquired by the instruction acquiring unit is deletion of the first frame, and the first frame is the first frame If it is not the first frame or the last frame of the first compression unit that is the compression unit to which one frame belongs, the image of the first frame is restored based on the compressed data of the first frame, and the image of the first frame and the first frame are restored. A restoration unit for restoring an image of the next frame of the first frame based on compressed data of the next frame of one frame;
A compression unit that compresses an image of the next frame of the first frame restored by the restoration unit as compressed data of a first frame;
For management information for managing the compressed data, a first front compression unit composed of a frame before the first frame of the first compression unit and a first frame of the first compression unit. The management information is changed to divide the first compression unit into a first rear compression unit composed of a later frame, and the compressed data of the next frame of the first frame is changed to the first rear compression unit. The management information changing unit for changing the management information so as to be a first frame;
An image management apparatus comprising: The image management apparatus according to claim 1,
When the instruction acquired by the instruction acquisition unit is deletion of the first frame, and the first frame is the first frame of the first compression unit,
The restoration unit restores the image of the first frame based on the compressed data of the first frame, and the first frame based on the image of the first frame and the compressed data of the next frame of the first frame. Restore the image of the next frame of
The compression unit compresses the image of the next frame of the first frame restored by the restoration unit into compressed data of the first frame,
The management information changing unit changes the management information so that a frame after the first frame in the first compression unit constitutes a new first compression unit, and the management information change unit changes the management information of the next frame of the first frame. An image management apparatus that changes the management information so that compressed data is a first frame of the new first compression unit. The image management apparatus according to claim 1 or 2,
When the instruction acquired by the instruction acquisition unit is deletion of the first frame, and the first frame is the last frame of the first compression unit,
The restoration unit does not restore an image,
The compression unit does not compress the image,
The management information changing unit is an image management device that changes the management information so that a frame before the first frame in the first compression unit constitutes a new first compression unit. The image management apparatus according to any one of claims 1 to 3,
When the instruction acquired by the instruction acquisition unit is the insertion of a new image at the position of the second frame, and the second frame is not the first frame of the second compression unit that is the compression unit to which the second frame belongs ,
The restoration unit restores the image of the second frame based on the compressed data of the second compression unit,
The compression unit compresses the new image as compressed data of the first frame, compresses the second frame image restored by the restoration unit as compressed data of the first frame,
The management information changing unit includes a second front compression unit configured by a frame before the second frame in the second compression unit and a frame after the second frame among the second compression units. Dividing the second compression unit into second rear compression units, and inserting a third compression unit as a new compression unit between the second front compression unit and the second rear compression unit. An image management device that changes the management information and changes the management information so that the compressed data of the new image is the first frame of the third compression unit. The image management apparatus according to any one of claims 1 to 4,
When the instruction acquired by the instruction acquisition unit is insertion of a new image at the position of the second frame, and the second frame is the first frame of the second compression unit,
The restoration unit does not restore an image,
The compression unit compresses the new image as compressed data of the first frame,
The management information changing unit changes the management information so that a third compression unit, which is a new compression unit, is inserted before the second compression unit, and converts the compressed data of the new image into a new compression unit. An image management apparatus that changes the management information so as to be the first frame of the third compression unit. The image management apparatus according to any one of claims 1 to 5,
When the instruction acquired by the instruction acquisition unit is the movement of the frame from the first frame to the position of the second frame,
The restoration unit, the compression unit, and the management information change unit are an image management apparatus that deletes the first frame and inserts the image of the first frame at the position of the second frame. The image management apparatus according to any one of claims 1 to 6,
When the instruction acquired by the instruction acquisition unit is the movement of the frame from the first frame to the position of the second frame,
The management information changing unit changes the management information so as to move the first frame to the position of the second frame, and changes the first frame in the first compression unit to which the first frame belongs. The management information is changed so as to change the configuration of the first compression unit based on the position, and the second frame is based on the position of the second frame in the second compression unit that is the compression unit to which the second frame belongs. 2. An image management apparatus that changes the management information so as to change the configuration of a compression unit. The image management apparatus according to any one of claims 1 to 7,
The management information changing unit is an image management device that changes the management information so that frame numbers are continuous after processing based on the instruction. An image management program for causing a computer to execute management for managing compressed data in which an image of a frame with a frame number is compressed,
Get the frame number of the specified frame and the processing instruction for that frame,
A plurality of continuous compression units composed of a plurality of consecutive frames, and the compressed data of the first frame in each compression unit is compressed data based on the image of only the first frame, and the first frame in each compression unit For compressed data in which compressed data of a frame other than the above is compressed based on the image of the immediately preceding frame, the instruction is deletion of the first frame, and the first frame is a compression unit to which the first frame belongs. If the first frame is not the first frame or the last frame, the first frame image is restored based on the compressed data of the first frame, and the first frame image and the next frame of the first frame are compressed. Restoring the image of the next frame of the first frame based on the data,
Compressing the restored image of the next frame of the first frame as compressed data of the first frame;
For management information for managing the compressed data, a first front compression unit composed of a frame before the first frame of the first compression unit and a first frame of the first compression unit. The management information is changed to divide the first compression unit into a first rear compression unit composed of a later frame, and the compressed data of the next frame of the first frame is changed to the first rear compression unit. An image management program for causing a computer to change the management information so as to be a first frame. An image management method for managing compressed data obtained by compressing a frame numbered frame image,
Get the frame number of the specified frame and the processing instruction for that frame,
A plurality of continuous compression units composed of a plurality of consecutive frames, and the compressed data of the first frame in each compression unit is compressed data based on the image of only the first frame, and the first frame in each compression unit For compressed data in which compressed data of a frame other than the above is compressed based on the image of the immediately preceding frame, the instruction is deletion of the first frame, and the first frame is a compression unit to which the first frame belongs. If the first frame is not the first frame or the last frame, the first frame image is restored based on the compressed data of the first frame, and the first frame image and the next frame of the first frame are compressed. Restoring the image of the next frame of the first frame based on the data,
Compressing the restored image of the next frame of the first frame as compressed data of the first frame;
For management information for managing the compressed data, a first front compression unit composed of a frame before the first frame of the first compression unit and a first frame of the first compression unit. The management information is changed to divide the first compression unit into a first rear compression unit composed of a later frame, and the compressed data of the next frame of the first frame is changed to the first rear compression unit. An image management method for executing the change of the management information so as to be a first frame.

Images