JP4695115B2 - Moving picture coding method, moving picture coding apparatus, moving picture coding program, and computer-readable recording medium recording the program - Google Patents

Description

  The present invention relates to a moving picture coding method and apparatus for adaptively selecting frame coding and field coding for interlaced video and executing the coding, and a moving picture used for realizing the moving picture coding method. The present invention relates to an image encoding program and a computer-readable recording medium on which the program is recorded.

  In recent years, H.264 / AVC which employs an encoding configuration as shown in FIG. 5 has been used as one of highly efficient moving picture encoding methods.

  In H.264 / AVC, according to the configuration of the encoding unit 200 shown in this figure, based on the motion vector detected by the motion vector detection unit 100, the prediction unit 201 includes an inverse quantization unit 205, an inverse orthogonal transform unit 206, and When motion prediction is performed from the decoded image created by the adder 207 to predict the current image, the subtractor 202 calculates a prediction error between the current image and the predicted image, and the DCT converter 203 calculates the prediction error. After performing the DCT transform on the quantization unit 204, the quantization unit 204 quantizes the DCT transform coefficient, the variable length coding unit 208 performs variable length coding on the quantized value, and the multiplexing unit 209 After multiplexing, the encoded data is output at a constant transfer rate via the buffer unit 210 in accordance with the control processing of the control unit 211.

In H.264 / AVC configured in this way, in order to realize more efficient encoding,
(1) Frame coding in which one picture is regarded as one frame for encoding (2) Field coding in which one picture is divided into a top field and a bottom field (3) A field code for each picture Level frame adaptive coding that performs coding by switching between coding and frame coding (4) Macroblock level field frame that performs coding by switching between field coding and frame coding in units of macroblock pairs Four encoding methods called adaptive encoding are employed.

  The frame coding method (1) is suitable for coding a moving image with little motion, and the field coding method (2) is suitable for coding a moving image with motion. In the image sequence, scenes with little motion and scenes with motion are mixed.

  For this reason, an encoding method is provided that adaptively switches between field encoding and frame encoding at the picture level (3).

  In addition, in one picture, a region with little motion and a region with motion are mixed, and in order to cope with this, field coding and frame are performed at a predetermined region level (macroblock level) in (4). An encoding method for adaptively switching between encoding is prepared.

  In general, the adaptive switching control schemes (3) and (4) are used, and by selecting a scheme that increases the coding efficiency for each picture or macroblock, the coding can be improved.

  In this regard, as a prior art, switching of field / frame encoding using motion information, which is configured by replacing the motion vector detection unit 100 in FIG. 5 with a field / frame encoding determination unit 300 shown in FIG. Methods are known (see, for example, Patent Documents 1 and 2).

In this prior art, the field dividing unit 301 divides the frame image into field images, the motion vector detecting unit 302 detects the motion vector for the frame image and the motion vector for the field image, and the evaluation function calculating unit In 303, whether or not the evaluation function value is calculated based on the calculated value used when detecting the motion vector, and the field / frame encoding determination unit 304 performs encoding with the field image according to the evaluation function value. It is determined whether the frame image is to be encoded, and the determination result output unit 305 outputs the determination result to the encoding unit 200.
JP-A-5-308627 Japanese Patent Laid-Open No. 5-95545

  However, in the prior art described in Patent Documents 1 and 2, motions are performed on two patterns of a field and a frame in order to determine whether encoding is performed using field encoding or frame encoding. Since it is necessary to perform processing for deriving information, that is, motion vector detection, there is a problem that the amount of calculation increases.

  In addition, in the prior art, since the motion vector detection process and the field / frame coding switching process are inseparable, the switching accuracy depends on the motion vector detection accuracy, and the motion vector detection accuracy is low. However, there is a problem that the switching accuracy decreases due to the influence.

  In view of the above, a new field / frame coding switching technique that minimizes the amount of computation and prevents the switching accuracy from being affected by the accuracy of information used in the field / frame coding switching processing. It needs to be realized.

  The present invention has been made in view of such circumstances, and when adaptively switching between field coding and frame coding for interlaced video, the amount of calculation is small and the switching accuracy is the motion vector. An object of the present invention is to provide a new moving picture coding technique that is not affected by detection accuracy and the like.

[I] First Configuration In order to achieve the above object, the moving image encoding apparatus of the present invention adaptively selects frame encoding and field encoding for interlaced video and executes encoding. For this purpose, (1) frame filter image generation means for generating a frame filter image by performing filter processing on an input image in units of a predetermined bandwidth, and (2) bandwidth of the input image (3) calculating first error information between the frame filter image generated by the frame filter image generation unit and the input image Frame filter image error information calculating means for performing, and (4) a field filter generated by the field filter image generating means Field filter image error information calculating means for calculating second error information between the image and the input image; and (5) first error information based on the magnitude relationship between the first error information and the second error information. A coding determining means for determining that the encoding is performed by frame encoding when the second error information is larger, and for performing the encoding by field encoding when the second error information is larger. To do.

  The moving image encoding method of the present invention realized by the operation of each of the above processing means can also be realized by a computer program, and this computer program is provided by being recorded on a suitable computer-readable recording medium. Alternatively, the present invention is realized by being provided via a network, installed when the present invention is carried out, and operating on a control means such as a CPU.

  In the moving image encoding apparatus of the present invention configured as described above, a filter process is performed on the input image in units of frames with a predetermined bandwidth, thereby generating a frame filter image and the input image. A field filter image is generated by performing filter processing in units of fields according to the bandwidth.

  Subsequently, error information between the generated frame filter image and the input image is calculated, and error information between the generated field filter image and the input image is calculated.

  Subsequently, based on the calculated two pieces of error information, it is determined whether or not the input image indicates a moving image with small motion, and it is determined that the input image indicates a moving image with small motion. In this case, it is determined that encoding is performed by frame encoding, and when it is determined that the moving image has a large motion, it is determined that encoding is performed by field encoding. To do.

  For example, one of the two error information values is corrected with a preset constant value, and the magnitude of the corrected error information value is compared with the value of the other error information not corrected, Based on the comparison result, when it is determined that the frame filter image does not contain more high frequency components than the field filter image, it is determined that the input image indicates a moving image with a small motion. Thus, when it is determined that encoding is to be performed by frame encoding and, conversely, when it is determined that the frame filter image includes more high-frequency components than the field filter image, the input image is a moving image with a large motion. It is determined that this is the case, and it is determined that encoding is to be performed by field encoding.

  In this way, in the moving image encoding apparatus of the present invention, when encoding is performed in units of input images, the input image indicates a moving image with small motion without performing motion vector detection processing. As a result, it is possible to determine whether to perform encoding by field encoding or encoding by frame encoding without performing motion vector detection processing.

[Ii] Second Configuration In order to achieve the above object, the moving picture coding apparatus of the present invention adaptively selects frame coding and field coding for interlaced video and executes coding. For this purpose, (1) frame filter image generation means for generating a frame filter image by performing filter processing on an input image in units of a predetermined bandwidth, and (2) bandwidth of the input image (4) a field filter image generation unit that generates a field filter image by performing filtering processing in units of fields, and (3) a division unit that divides the input image into pixel groups configured in predetermined pixel units. for each divided divided pixel group dividing means, to calculate the first error information of an input image and generated frame filtered image frame filtered image generating unit Frame filter image error information calculating means (5) for each divided divided pixel group dividing means, field filtered image to calculate the second error information field filter image generated field filtered image generating means and the input image When the first error information is larger on the basis of the magnitude relationship between the first error information and the second error information for each of the divided pixel groups divided by the error information calculating means and (6) the dividing means , It is determined to include encoding determining means that determines that encoding is to be performed by frame encoding and determines that encoding is to be performed by field encoding when the second error information is larger .

  The moving image encoding method of the present invention realized by the operation of each of the above processing means can also be realized by a computer program, and this computer program is provided by being recorded on a suitable computer-readable recording medium. Alternatively, the present invention is realized by being provided via a network, installed when the present invention is carried out, and operating on a control means such as a CPU.

  In the moving image encoding apparatus of the present invention configured as described above, a filter process is performed on the input image in units of frames with a predetermined bandwidth, thereby generating a frame filter image and the input image. A field filter image is generated by performing filter processing in units of fields according to the bandwidth.

  Subsequently, a divided pixel group is generated by dividing the input image into pixel groups configured in predetermined pixel units.

  Subsequently, error information between the generated frame filter image and the input image is calculated for each divided pixel group, and error information between the generated field filter image and the input image is calculated.

  Subsequently, for each divided pixel group, based on the two pieces of calculated error information, it is determined whether or not the image of the divided pixel group indicates a moving image with a small motion. If it is determined that the image is to be encoded, it is determined that the encoding is performed by frame encoding, and if it is determined that the moving image has a large motion, the field encoding is performed. To perform encoding.

  For example, for each divided pixel group, one of two error information values is corrected with a preset constant value, and the corrected error information value and the other error information value not corrected When the sizes are compared and it is determined that the frame filter image does not contain a lot of high frequency components compared to the field filter image based on the comparison result, the image of the divided pixel group is a moving image with a small motion. In the case where it is determined that the frame encoding is to be performed, it is determined that the frame filter image includes more high-frequency components than the field filter image. Then, it is determined that the image of the divided pixel group indicates a moving image having a large motion, and it is determined to perform the encoding by field encoding.

  As described above, in the moving image encoding device of the present invention, when encoding is performed in units of divided pixel group images, the motion of the divided pixel group is small in motion without performing motion vector detection processing. By being able to determine whether or not an image is shown, it is possible to determine whether to perform encoding using field encoding or frame encoding without performing motion vector detection processing. become able to.

  According to the present invention, when frame coding and field coding are adaptively selected for interlaced video and moving image coding is performed, a motion vector detection process is not performed, and an image to be coded is detected. Whether or not a moving image with a small amount of motion can be determined can be determined, so that whether to perform frame encoding or field encoding without performing motion vector detection processing. Will be able to decide.

  Thus, according to the present invention, when video encoding is performed by adaptively selecting frame coding and field coding for interlaced video, the amount of calculation is small and the detection accuracy of a motion vector or the like is low. Without being affected, it is possible to determine whether encoding is performed using frame encoding or field encoding.

  Hereinafter, the present invention will be described in detail according to embodiments.

  FIG. 1 shows an embodiment of a moving picture encoding apparatus 1 having the present invention.

  Here, the motion vector detection unit 100 shown in the figure corresponds to the motion vector detection unit 100 shown in FIG. 5, and the encoding unit 200 shown in the figure corresponds to the encoding unit 200 shown in FIG. Is.

  The moving image encoding apparatus 1 according to the present invention performs encoding by adaptively selecting field encoding and frame encoding for interlaced video, and stores an input original image. Field / frame coding decision that is configured to realize the present invention between the unit 400 and the motion vector detection unit 100 and decides whether to perform coding by field coding or frame coding The unit 10 is provided.

  The field / frame encoding determination unit 10 includes a field dividing unit 11, a filter processing unit 12, a filter image storage unit 13, an error information calculation unit 14, an error information storage unit 15, and a field / frame encoding determination. Unit 16 and determination result output unit 17.

  The field dividing unit 11 divides the original image data B_o read from the original image storage unit 400 into top field image data B_tfl and bottom field image data B_bfl.

  The filter processing unit 12 performs frame processing on the frame image data B_fr that is the original image data B_o with a predetermined bandwidth r to generate frame filter image data B_fr_fil and stores it in the filter image storage unit 13. By filtering the top field image data B_tfl divided by the field dividing unit 11 with the bandwidth r, the top field filter image data B_tfl_fil is generated and stored in the filter image storage unit 13, and the field dividing unit The bottom field filter image data B_bfl_fil is generated by performing a filtering process with the bandwidth r on the 11 divided bottom field image data B_bfl, and stored in the filter image storage unit 13.

  The error information calculation unit 14 calculates error information P_fr between the frame filter image data B_fr_fil generated by the filter processing unit 12 and the original image data B_o according to PSNR (Peak Signal to Noise Ratio) and the like, and stores the error information P_fr in the error information storage unit 15. The error information P_tfl between the top field filter image data B_tfl_fil generated by the filter processing unit 12 and the original image data B_o is calculated and stored in the error information storage unit 15, and the bottom field filter generated by the filter processing unit 12 is stored. Error information P_bfl between the image data B_bfl_fil and the original image data B_o is calculated and stored in the error information storage unit 15.

  Here, the error information calculation unit 14 may calculate the error information according to a definition other than the PSNR, but in the following, it is assumed that the error information is calculated according to the PSNR for convenience of explanation.

Based on the error information P_fr, P_tfl, and P_bfl calculated by the error information calculation unit 14, the field / frame coding determination unit 16
(P_tfl + P_bfl) / 2> P_fr + a Equation (1)
If this condition is satisfied, it is determined that the input image is to be encoded by field coding. If this condition is not satisfied, the input image is It is determined that encoding is performed by frame encoding.

  Here, a in Equation (1) is a constant and is set according to the image size, the characteristics of the filter used, and the like.

  The determination result output unit 17 outputs the determination result of the field / frame encoding determination unit 16 to the motion vector detection unit 100.

  FIG. 2 shows a flowchart executed by the field / frame encoding determination unit 10 configured as shown in FIG.

  Next, processing executed by the field / frame encoding determination unit 10 configured as shown in FIG. 1 will be described in detail according to this flowchart.

  First, the field / frame encoding determination unit 10 inputs the original image data B_o in step S101, and then in step S102, the input original image data B_o is converted into the top field image data B_tfl and the bottom field. The image data is divided into B_bfl.

  Subsequently, in step S103, frame filter image data B_fr_fil is generated by performing filter processing with a predetermined bandwidth r on the frame image data B_fr that is the original image data B_o.

  Subsequently, in step S104, the top field filter image data B_tfl_fil is generated by performing the filtering process on the top field image data B_tfl obtained in the process of step S102 with the bandwidth r.

  Subsequently, in step S105, the bottom field filter image data B_bfl_fil is generated by performing the filtering process with the bandwidth r on the bottom field image data B_bfl obtained in the process of step S102.

  Subsequently, in step S106, error information P_fr between the frame filter image data B_fr_fil generated in the process of step S103 and the original image data B_o is calculated.

  Subsequently, in step S107, error information P_tfl between the top field filter image data B_tfl_fil generated in the process of step S104 and the original image data B_o is calculated.

  Subsequently, in step S108, error information P_bfl between the bottom field filter image data B_bfl_fil generated in the process of step S105 and the original image data B_o is calculated.

  Here, in steps S106 to S108, error information is calculated according to the PSNR.

  When the error information is calculated according to the PSNR, the closer the filter image data is to the original image data (the better the image quality), the larger the PSNR that is the error information between the filter image data and the original image data. On the other hand, when the movement of the image is large, the image shift between the top field and the bottom field increases, so that the frame image data having a longer sampling time interval has a smaller correlation with adjacent pixels than the field image data. Therefore, the image quality of the frame filter image data is lower than that of the field filter image data, and the PSNR shows a small value.

From now on, in step S109,
(P_tfl + P_bfl) / 2> P_fr + a Equation (1)
It is determined whether or not the motion of the image is large. Here, a is a constant as described above.

  When it is determined that the mathematical expression (1) is established according to this determination process, it is determined that the motion of the image is large, and the process proceeds to step S110 to determine that the input image is to be encoded by field encoding. Then, control is passed to the motion vector detection process and the encoding process, and the process ends.

  On the other hand, when it is determined according to this determination processing that the mathematical expression (1) is not established, it is determined that the motion of the image is small, and the process proceeds to step S111 to encode the input image by frame encoding. , Control is passed to the motion vector detection process and the encoding process, and the process ends.

  Next, processing executed by the field / frame coding determination unit 10 configured as shown in FIG. 1 will be described using a specific example.

  The image size of the original image data is 1920 × 1080, the filter bandwidth is r = 0.5 (a low-pass filter that cuts the frequency component in half in the horizontal and vertical directions), and the constant a is a = 2.

  First, the field dividing unit 11 divides the original image data into top field image data B_tfl and bottom field image data B_bfl to generate a field picture (1920 × 540). These are input to the filter processing unit 12 and subjected to filter processing with a bandwidth of 0.5 to generate top field filter image data B_tfl_fil and bottom field filter image data B_bfl_fil.

  On the other hand, when the original image data is used as a frame picture, it is directly input to the filter processing unit 12 and is subjected to filter processing with a bandwidth of 0.5 to generate frame filter image data B_fr_fil.

  Subsequently, the error information calculation unit 14 measures the PSNR of each filter image data with respect to the original image data, thereby, for example, P_fr = 20 [dB], P_tfl = 26 [dB], P_bfl = 24 [dB]. obtain.

  Subsequently, the field / frame encoding determination unit 16 determines whether or not Expression (1) is established according to these PSNR values. In the case of these PSNR values, since Equation (1) is established, the field / frame encoding determination unit 16 determines to perform encoding by field encoding, and in response to this, a determination result output unit 17 outputs to the motion vector detection unit 100 that encoding is performed by field encoding.

  On the other hand, when the error information calculation unit 14 obtains, for example, P_fr = 30 [dB], P_tfl = 26 [dB], and P_bfl = 24 [dB], the field / frame encoding determination unit 16 In accordance with the PSNR value, it is determined that Equation (1) does not hold, and it is determined that encoding is performed by frame encoding. In response to this, the determination result output unit 17 performs encoding by frame encoding. Is output to the motion vector detection unit 100.

  In this way, the field / frame coding determination unit 10 can determine whether to perform field coding or frame coding without performing motion vector detection processing. Therefore, the determination can be performed with a small amount of calculation and without being affected by the detection accuracy of the motion vector or the like.

  FIG. 3 shows another embodiment of the moving picture encoding apparatus 1 comprising the present invention. Here, the same components as those shown in FIG. 1 are indicated by the same symbols.

  In the case of following this embodiment, the moving image encoding apparatus 1 of the present invention newly includes a pixel group dividing unit 18 and a divided image storage unit 19, an error information calculation unit 14, an error information storage unit 15, a field / frame. The encoding determination unit 16 and the determination result output unit 17 adopt a configuration in which processing corresponding to the execution is performed.

  The pixel group dividing unit 18 reads the original image data B_o from the original image storage unit 400, divides it into pixel groups configured in predetermined pixel units, stores them in the divided image storage unit 19, and receives the frame from the filter image storage unit 13. The filter image data B_fr_fil is read out, divided into those pixel groups and stored in the divided image storage unit 19, and the top field filter image data B_tfl_fil is read out from the filter image storage unit 13 and divided into those pixel groups to be divided images. The data is stored in the storage unit 19, and the bottom field filter image data B_bfl_fil is read from the filter image storage unit 13, divided into those pixel groups, and stored in the divided image storage unit 19.

  In response to this, the error information calculation unit 14 calculates error information P_fr between the frame filter image data B_fr_fil and the original image data B_o for each divided pixel group divided by the pixel group dividing unit 18 in accordance with PSNR, thereby obtaining error information. The error information P_tfl between the top field filter image data B_tfl_fil and the original image data B_o is calculated and stored in the error information storage unit 15, and the bottom field filter image data B_bfl_fil and the original image data B_o are stored in the storage unit 15. Error information P_bfl is calculated and stored in the error information storage unit 15.

In response to this, the field / frame encoding determination unit 16 determines that the error information P_fr, P_tfl, P_bfl for each divided pixel group divided by the pixel group dividing unit 18 is:
(P_tfl + P_bfl) / 2> P_fr + a Equation (1)
If this condition is satisfied, it is determined that the image of the divided pixel group is to be encoded by field encoding. If this condition is not satisfied, Then, it is determined that the image of the divided pixel group is to be encoded by frame encoding.

  In response to this, the determination result output unit 17 outputs the determination result of the field / frame encoding determination unit 16 to the motion vector detection unit 100.

  FIG. 4 shows a flowchart executed by the field / frame encoding determination unit 10 configured as shown in FIG.

  Next, processing executed by the field / frame coding determination unit 10 configured as shown in FIG. 3 will be described in detail according to this flowchart.

  The field / frame encoding determination unit 10 first inputs the original image data B_o in step S201, and then in step S202, the input original image data B_o is converted into the top field image data B_tfl and the bottom field. The image data is divided into B_bfl.

  Subsequently, in step S203, frame filter image data B_fr_fil is generated by filtering the frame image data B_fr, which is the original image data B_o, with a predetermined bandwidth r.

  Subsequently, in step S204, the top field filter image data B_tfl_fil is generated by filtering the top field image data B_tfl obtained in the process of step S202 with the bandwidth r.

  Subsequently, in step S205, bottom field filter image data B_bfl_fil is generated by performing filter processing with the bandwidth r on the bottom field image data B_bfl obtained in step S202.

  Subsequently, in step S206, the original image data B_o is divided into pixel groups configured in predetermined pixel units, the frame filter image data B_fr_fil is divided into those pixel groups, and the top field filter image data B_tfl_fil is converted into those pixel groups. Dividing into pixel groups, the bottom field filter image data B_bfl_fil is divided into these pixel groups.

  Subsequently, in step S207, it is determined whether or not there is an unprocessed divided pixel group. If it is determined that there is an unprocessed divided pixel group, the process proceeds to step S208, and an unprocessed divided pixel group is obtained. Select one group.

  Subsequently, in step S209, the error information P_fr between the frame filter image data B_fr_fil generated in the process of step S203 and the original image data B_o is calculated for the selected divided pixel group according to the PSNR, and generated in the process of step S204. Error information P_tfl between the top field filter image data B_tfl_fil and the original image data B_o is calculated, and error information P_bfl between the bottom field filter image data B_bfl_fil and the original image data B_o generated in step S205 is calculated.

Subsequently, in step S210, for the selected divided pixel group,
(P_tfl + P_bfl) / 2> P_fr + a Equation (1)
It is determined whether or not the motion of the image is large.

  When it is determined that the mathematical expression (1) is established according to this determination processing, it is determined that the motion of the image is large, the process proceeds to step S211, and the image of the selected divided pixel group is encoded by field encoding. To return to step S207.

  On the other hand, if it is determined in accordance with this determination processing that Equation (1) does not hold, it is determined that the motion of the image is small, and the process proceeds to step S212 to frame-code the image of the selected divided pixel group. And the process returns to step S207.

  When it is determined in step S207 that all the divided pixel groups have been selected by repeating the processing of step S207 to step S212 in this way, the process proceeds to step S213, and which of the images of each divided pixel group is selected. Control is passed to the motion vector detection process and the encoding process while notifying whether or not encoding is to be used, and the process is terminated.

  Next, processing executed by the field / frame encoding determination unit 10 configured as shown in FIG. 3 will be described using a specific example.

  The image size of the original image data is 1920 × 1080, the filter bandwidth is r = 0.5 (a low-pass filter that cuts frequency components in half in the horizontal and vertical directions), the constant a is a = 2, and the division is performed. The pixel group is a rectangular block with a size of 16 × 16.

  First, the field dividing unit 11 divides the original image data into top field image data B_tfl and bottom field image data B_bfl to generate a field picture (1920 × 540). These are input to the filter processing unit 12 and subjected to filter processing with a bandwidth of 0.5 to generate top field filter image data B_tfl_fil and bottom field filter image data B_bfl_fil.

  On the other hand, when the original image data is used as a frame picture, it is directly input to the filter processing unit 12 and is subjected to filter processing with a bandwidth of 0.5 to generate frame filter image data B_fr_fil.

  Subsequently, the pixel group dividing unit 18 divides the original image data B_o and the frame filter image data B_fr_fil into 16 × 16 block units, and the top field filter image data B_tfl_fil and the bottom field filter image data B_bfl_fil and Is divided into 16 × 8 block units.

  Subsequently, the error information calculation unit 14 measures the PSNR with respect to the original image data of each block unit filter image data, and, for example, P_fr = 20 [dB], P_tfl = 26 [dB], P_bfl = 24 [dB]. ] Is obtained.

  Subsequently, the field / frame encoding determination unit 16 determines whether or not Expression (1) is established according to these PSNR values. In the case of these PSNR values, since Equation (1) is established, the field / frame encoding determination unit 16 determines to perform encoding by field encoding, and in response to this, a determination result output unit 17 outputs to the motion vector detection unit 100 that encoding is performed by field encoding.

  On the other hand, when the error information calculation unit 14 obtains, for example, P_fr = 30 [dB], P_tfl = 26 [dB], and P_bfl = 24 [dB], the field / frame encoding determination unit 16 In accordance with the PSNR value, it is determined that Equation (1) does not hold, and it is determined that encoding is performed by frame encoding. In response to this, the determination result output unit 17 performs encoding by frame encoding. Is output to the motion vector detection unit 100.

  In this way, the field / frame encoding determination unit 10 determines whether to perform the encoding by the field encoding or the frame encoding on the divided pixel group without performing the motion vector detection process. Therefore, the determination can be performed with a small amount of calculation and without being affected by the detection accuracy of the motion vector or the like.

  Although the present invention has been described according to the illustrated embodiment, the present invention is not limited to this.

  For example, in the embodiment, the average error information value of the top field filter image data and the bottom field filter image data is used on the left side of Equation (1). Even if the error information value is used, the same effect can be obtained.

  The value of the constant a varies depending on the type of error information (PSNR, mean square error, etc.), but the same effect can be achieved by using a value corresponding to each error information value. .

  Further, the bandwidth r can take a value of 0 <r <1, and the filter characteristic varies depending on the value, and the constant a varies accordingly, but the same effect can be obtained.

  The present invention can be applied when performing moving image coding of interlaced video, and can adaptively switch field / frame coding in moving image coding based on the frequency characteristics of a picture. Therefore, the switching can be executed with a small amount of processing calculation and with high accuracy.

  In addition, the prefiltering process and the field / frame determination process can be performed collectively by performing the filtering process in the filter processing unit 12 as a prefiltering process for the purpose of removing noise and improving the encoding efficiency. Therefore, it is possible to realize high functionality according to the present invention without increasing the amount of calculation.

It is an example of one Embodiment of the moving image encoder of this invention. It is a flowchart which a field / frame encoding determination part performs. It is another example of embodiment of the moving image encoder of this invention. It is a flowchart which a field / frame encoding determination part performs. It is explanatory drawing of H.264 / AVC. It is explanatory drawing of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Moving image encoder 10 Field / frame encoding determination part 11 Field division part 12 Filter processing part 13 Filter image memory | storage part 14 Error information calculation part 15 Error information memory | storage part 16 Field / frame encoding determination part 17 Determination result output part 100 motion vector detection unit 200 encoding unit 400 original image storage unit

Claims (8)

A moving image coding method for adaptively selecting frame coding and field coding for interlaced video, and performing coding,
Generating a frame filter image by performing a filtering process on a frame basis with a predetermined bandwidth on the input image;
Generating a field filter image by performing filtering on the input image in units of fields according to the bandwidth;
Calculating first error information between the frame filter image and the input image;
Calculating second error information between the field filter image and the input image;
Based on the magnitude relationship between the two calculated error information , when the first error information is larger, it is determined that encoding is performed by frame coding, and when the second error information is larger. , further comprising a step of determining to perform coding in field coding,
A moving image encoding method as a feature. A moving image coding method for adaptively selecting frame coding and field coding for interlaced video, and performing coding,
Generating a frame filter image by performing a filtering process on a frame basis with a predetermined bandwidth on the input image;
Generating a field filter image by performing filtering on the input image in units of fields according to the bandwidth;
Dividing the input image into pixel groups configured in predetermined pixel units;
Calculating first error information between the frame filter image and the input image for each of the divided divided pixel groups;
Calculating second error information between the field filter image and the input image for each of the divided divided pixel groups;
For each of the divided pixel groups, based on the magnitude relationship between the two calculated error information, when the first error information is larger, it is determined that encoding is performed by frame encoding, If more of the second error information is larger, that comprises the steps of: determining to perform coding in field coding,
A moving image encoding method as a feature. In the moving image encoding method according to claim 1 or 2,
The second error information includes error information between one of the top field filter image and the bottom field filter image and the input image, or error information between the top field filter image and the input image, and the bottom field filter image and the input. It is the average value of error information with the image,
A moving image encoding method as a feature. In the moving image encoding method according to claim 1, 2 or 3 ,
In the determining step, one of the two calculated error information values is corrected with a preset constant value, and the corrected error information value is used for the magnitude relation comparison .
A moving image encoding method as a feature. A video encoding apparatus that performs encoding by adaptively selecting frame encoding and field encoding for interlaced video,
Means for generating a frame filter image by performing a filtering process in units of frames with a predetermined bandwidth on the input image;
Means for generating a field filter image by performing filtering on the input image in units of fields according to the bandwidth;
Means for calculating first error information between the frame filter image and the input image;
Means for calculating second error information between the field filter image and the input image;
Based on the magnitude relationship between the two calculated error information , when the first error information is larger, it is determined that encoding is performed by frame coding, and when the second error information is larger. , further comprising a means for determining to perform coding in field coding,
A moving image encoding device. A video encoding apparatus that performs encoding by adaptively selecting frame encoding and field encoding for interlaced video,
Means for generating a frame filter image by performing a filtering process in units of frames with a predetermined bandwidth on the input image;
Means for generating a field filter image by performing filtering on the input image in units of fields according to the bandwidth;
Means for dividing the input image into pixel groups configured in predetermined pixel units;
Means for calculating first error information between the frame filter image and the input image for each divided pixel group;
Means for calculating second error information between the field filter image and the input image for each of the divided divided pixel groups;
Means for determining whether to perform encoding by frame encoding or encoding by field encoding based on the calculated two pieces of error information for each divided pixel group,
For each of the divided pixel groups, based on the magnitude relationship between the two calculated error information, when the first error information is larger, it is determined that encoding is performed by frame encoding, If more of the second error information is larger, further comprising a means for determining to perform coding in field coding,
A moving image encoding device. A moving picture coding program for causing a computer to execute processing used to realize the moving picture coding method according to any one of claims 1 to 4 . A computer-readable recording medium having recorded thereon a moving picture coding program for causing a computer to execute processing used to realize the moving picture coding method according to any one of claims 1 to 4 .

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