JP5034717B2 - Decoding device and decoding method - Google Patents

Description

The present invention relates to a decoding apparatus and a decoding method for quickly displaying still images from a recording medium on which a plurality of still image data having different resolutions formed from one image is recorded.

2. Description of the Related Art Conventionally, a recording / reproducing apparatus for recording / reproducing still image data supplied from the outside on a recording medium such as an optical disk is known.
This recording / reproducing apparatus is generally supplied with high-resolution image data as still image data, and the high-resolution image data is compressed and encoded by the JPEG method or the like and recorded on a recording medium.
In this case, intermediate resolution still image data obtained by thinning out high-resolution still image data by a factor of 1 and index still image data thinned by a factor of a few tenths are created. Different still image data is recorded on the recording medium.

When still image data is read out from a recording medium on which still image data with different resolutions are recorded and displayed, first, a plurality of the lowest resolution still image data to be index images are read out and displayed. The desired still image is selected. Then, the intermediate resolution image data of the selected still image is read and displayed on the display device.
Here, the reason why the intermediate resolution image data is read and displayed is that the amount of data of the high resolution still image data is large, and it takes time to read the data and display it on the display device. In particular, when the recording medium is an optical disk, the time required for access becomes long.

However, when displaying high-resolution still image data, it takes time to read out and display the high-resolution still image data, and there is a problem that the entire image cannot be confirmed quickly.
SUMMARY OF THE INVENTION An object of the present invention is to provide a still image display method capable of quickly confirming the entire displayed image when displaying high-resolution still image data.

To achieve the above object, in a decoding device for decoding encoded image data, the first encoded image data compressed by converting the image data to the first resolution is decoded to obtain the first image data. Decoding that generates the second image data by generating the second image data by decoding the compressed second encoded image data by converting the image data to a second resolution that is higher than the first resolution Determining means for determining whether to display the first image data, to replace the first image data with the second image data, or to display the second image data And based on the determination result of the determination unit, the decoding unit is controlled and the first image data generated by the decoding unit is generated by the decoding unit while being displayed on the display unit. The 2 encoded image data is decoded, and the first image data displayed on the display means is rewritten and overwritten by one horizontal line while being replaced with the whole of the second image data. , and a control means for controlling said decoding means, said second encoded image data, a first mode which does not compress the second encoded image data, said first compression ratio A second mode for compressing into the second encoded image data and a third mode for compressing into the second encoded image data at a second compression rate higher than the first compression rate. It is recorded on the recording medium in the mode selected by the selection operation unit to be selected, and the control unit controls the decoding unit when the second mode is selected by the selection operation unit.

In the decoding method for decoding the encoded image data, the image data is converted to the first resolution and the compressed first encoded image data is decoded to generate the first image data. a decoding step of generating a second image data by decoding the second encoded image data compressed by converting the second resolution is a first resolution higher than the resolution of the data, the first A determination step for determining whether to display the first image data, to replace the first image data with the second image data, or to display the second image data; and based on the determination result, and controls the decoding step, generating of the said decoding step while being displayed across the display means of the first image data generated by the decoding step The second encoded image data is decoded, and the first image data displayed on the display means is replaced by the entire second image data while being rewritten one horizontal line at a time. A control step for controlling a decoding step, wherein the second encoded image data includes a first mode in which the second encoded image data is not compressed into the second encoded image data, and the second code at a first compression rate. Of selecting a mode from a second mode for compressing into encoded image data and a third mode for compressing into the second encoded image data at a second compression rate higher than the first compression rate The recording step is recorded on the recording medium in the mode selected by the operation unit, and the decoding step is controlled when the second mode is selected by the selection operation unit in the control step.

Further, in the decoding device for decoding the encoded image data, the first encoded image data obtained by compressing the image data at the first compression rate is decoded to generate the first image data, and the image data is Decoding means for decoding second encoded image data compressed at a second compression rate lower than the first compression rate to generate second image data; and displaying the first image data Or a determination means for determining whether to display the first image data by replacing the first image data with the second image data, or based on a determination result of the determination means, Controlling the decoding means to decode the second encoded image data generated by the decoding means while displaying the entire first image data generated by the decoding means on the display means; , The display means As is to be displayed in place of the whole of the second image data while rewriting one by one horizontal line the displayed first image data, and a control means for controlling said decoding means, said second The encoded image data includes a first mode in which the encoded image data is not compressed into the second encoded image data, a second mode in which the encoded image data is compressed into the second encoded image data at a first compression rate, and the first mode. Of the third mode for compressing the second encoded image data at the second compression rate higher than the compression rate, the mode is recorded on the recording medium in the mode selected by the selection operation unit for selecting the mode, The control unit controls the decoding unit when the second mode is selected in the selection operation unit.

Since the present invention is configured as described above, when high-resolution still image data is displayed, first, the still image data having a resolution that can be quickly read and displayed is read and the entire image is displayed. In this way, since the display image is rewritten with the high-resolution still image data read during display, the entire still image can be displayed quickly. Therefore, it is possible to shorten the time until the entire image is confirmed.
Further, it is possible to provide a progressing function in which the quality of the displayed image is gradually improved with the passage of time.

FIG. 1 shows a block diagram of an optical disc recording / reproducing apparatus to which a still image display method according to an embodiment of the present invention is applied.
The optical disk recording / reproducing apparatus shown in FIG. 1 includes a scanner unit 1 that reads an image from a film, a photograph, and the like, a video input unit 2 that captures image data from a video tape recorder, a video camera, a still camera, and the like. A storage unit 11 that records and reproduces image data captured from the unit 1 or the video input unit 2.

The image data captured from the scanner unit 1 and the video input unit 2 is stored in the frame memory 3, and the monitor device 8 that displays the image data read from the frame memory 3 and the frame memory 3 read the image data. A printer unit 9 for printing image data is provided in the optical disc recording / reproducing apparatus. Note that image data is converted into an analog signal by the digital / analog converter 7 and supplied to the monitor device 8 to the monitor device 8.
The optical disk recording / reproducing apparatus includes a memory controller 4 that controls writing and reading of image data to and from the frame memory 3, a central processing unit (CPU) 5 that controls the overall operation of the optical disk recording / reproducing apparatus, and a scanner unit. 1 is provided with an operation unit 6 equipped with keys for instructing image data capture by 1 and printing instructions for the printer unit 9.

  The storage unit 11 further includes an interface (I / F) 12 to which image data read from the frame memory 3 is supplied, and raster / block conversion for dividing the image data into blocks of predetermined pixels suitable for compression encoding processing. The circuit 13 performs compression processing that performs compression coding processing and entropy coding processing on the image data that has been blocked during recording, and performs decompression decoding processing and inverse entropy decoding processing on the image data compressed during playback. A compression / expansion circuit 14 that performs expansion processing, a memory 15 that is used as a temporary storage buffer at the time of raster / block conversion, and image data from the compression / expansion circuit 14 are temporarily stored during recording, and disk recording / reproduction during reproduction A buffer memory 16 in which image data read from the unit 17 is temporarily stored; To disk 18 records the image data, and a disk recording and reproducing unit 17 for reading out image data recorded on the optical disk 18.

  The storage unit 11 includes a system controller 19 that controls the overall operation of the storage unit 11, an operation unit 20 that includes keys for instructing recording and reproduction of image data, and a display that indicates image data information and the like. Part 21.

Next, the operation of the still image recording / reproducing apparatus configured as described above will be described.
First, the case where a desired image is recorded on the optical disk 18 will be described. The user operates the operation unit 6 to specify whether the image data is to be imported to the scanner unit 1 or the video input unit 2. Then, the output destination of the captured image data is designated as the storage unit 11. As a result, the CPU 5 controls the designated one of the scanner unit 1 or the video input unit 2 to the operating state.

  The scanner unit 1 can read images of both a reflective original and a transparent original, and can read E size, L size, and A6 size photographs as a reflective original, 35 mm as a transparent original, and a brownie size. The negative film can be read. When any of these documents is mounted on the document reading table, the document is read by the CCD sensor, and image data is formed and output.

The video input unit 2 also receives composite signals from video tape recorders, video signals having a luminance (Y) / chroma (C) separate format, and video signals having been formatted with RGB primary color signals. Three format video signals can be input. The input video signal is unified into an RGB format video signal by a built-in video processing unit, further converted into digital image data and output.
The image data formed by the scanner unit 1 or the video input unit 2 is, for example, high-resolution image data in which the horizontal direction is 1536 pixels and the vertical direction is 1024 pixels, and this image data is supplied to the frame memory 3. And memorized.

The writing of the image data to the frame memory 3 is performed under the control of the memory controller 4. The image data read from the frame memory 3 is converted into an analog image signal by the D / A converter 7 and displayed on the monitor device 8.
Here, when the user operates the REC key of the operation unit 20 provided in the storage unit 11, the storage unit 11 is in the REC state. That is, the system controller 19 controls the interface 12 so as to capture the image data stored in the frame memory 3. As a result, the image data taken into the storage unit 11 via the interface 12 is input to the raster / block conversion circuit 13 and is used in block units suitable for encoding processing by using the memory 15 as a temporary storage buffer. Divided.

  The blocked image data is input to the compression / expansion circuit 14 and subjected to JPEG compression processing. In this case, the compression process is performed by DCT (Discrete Cosine Transform) means, quantization means, and variable length coding means. The DCT means performs a kind of Fourier transform on the image data, and decomposes it into a DC (direct current) component and each frequency component from a low frequency term to a high frequency term. In general, image data has a property of concentrating on low frequency terms after DCT. Therefore, the DCT image data is quantized by a quantization means having a quantization table in which the quantization step is increased from the low frequency term toward the high frequency term. As a result, the image data can be compressed. Further, the image data is further compressed by performing variable length coding that assigns a short code to a value with a high appearance probability and assigns a long code to a value with a low appearance probability.

  Next, the compressed image data is written in the buffer memory 16 by the DMA method, read out from the buffer memory 16 at the timing of the disk recording / reproducing unit 17, and recorded on the optical disk 18 by the disk recording / reproducing unit 17. The optical disk 18 may be a mini disk (MD). Note that MD is a magneto-optical recording method, and its storage capacity is 140 MB.

The optical disc 18 is recorded with main image mode image data, standard (SD) mode image data, and index image data formed from one piece of image data. This image mode includes a non-compression mode in which image data is not compressed, a fine mode in which image data is compressed to 1/5 (RGB standard), and a normal mode in which image data is compressed to 1/16. It is set to 768 × 576 pixels in the PAL system. The image data in the SD mode has a data amount smaller than that of the main image and is compressed to 1/16, and has an image size of the VGA standard (640 × 480 pixels). The image size of the index image data is 80 × 60 pixel image data.
Note that which mode of the main image mode is set is set by the user operating the operation unit 20.

  The image data in the main image mode and the image data in the SD mode can be created by thinning out the image data stored in the frame memory 3, but the quantization table of the compression / decompression circuit 14 is changed. Since the compression ratio can be changed by this, the image data in the main image mode and the image data in the SD mode can be created thereby. The image data in the main image mode and the image data in the SD mode created in this way are recorded on the optical disc 18 as described above.

Next, an operation of reproducing image data from the optical disk 18 on which image data of three types of resolutions are recorded and displaying the image data on the monitor device 8 will be described.
The user operates the operation unit 20 to instruct display of image data recorded on the optical disc 18. Thereby, the system controller 19 controls the disc recording / reproducing unit 17 to reproduce the image data. The image data reproduced by the disk recording / reproducing unit 17 is written in the buffer memory 16 by the DMA method, read and decompressed at the timing of the compression / expansion circuit 14, and further blocked by the raster / block conversion circuit 13. To a raster form and input to the interface 12.
Then, the reproduced image data is written into the frame memory 3 through the interface 12 and the interface block 10.

Further, the image data read from the frame memory 3 is converted into an analog signal by the D / A converter 7 and displayed on the monitor device 8.
In this case, the user can select the display mode of the quick mode, the auto mode, and the main mode. When the quick mode is selected, the SD mode image is quickly displayed on the monitor device 8. Since the SD mode is compressed to 1/16 as described above, the time until one SD mode image data is read from the optical disk 18 and displayed is about 1 second. The displayed image can be switched.

The auto mode is a mode that embodies the still image display method of the present invention. When the auto mode is set, first, SD mode image data is read from the optical disc 18 and displayed on the monitor device 8 quickly. While the mode image is being displayed, the image data in the main image mode is read from the optical disk 18 and reproduced, and the image displayed on the monitor device 8 is changed to the image data in the main image mode while rewriting one horizontal line at a time. It is to be switched.
According to the auto mode, an image is displayed on the monitor device 8 as soon as playback is instructed, and the image on the monitor device 8 is replaced with the image in the main image mode as soon as the image data in the main image mode is played back. The user can quickly check the entire image. In addition, the quality of the displayed image is gradually improved as time passes, and a mode having a so-called progressing function is set.

Further, the main mode is a mode in which the main image data is read from the optical disk 18 and reproduced, and the main image is displayed on the monitor device 8. In this mode, since the main image data is often set to a large capacity, it takes time until the image is displayed on the monitor display 8 after the reproduction is instructed.
For example, it takes about 2 seconds to display in the fine mode, and about 5 seconds in the non-compression mode. In normal mode, it takes about 1 second.

Next, FIG. 2 shows a flowchart of an operation process in which image data is reproduced from the optical disk 18 on which image data of three kinds of resolutions are recorded and displayed on the monitor device 8.
In this flowchart, when the user gives a reproduction instruction, it is determined in step S10 whether or not the quick mode has been instructed. If the quick mode is instructed and it is determined that the answer is yes (Y), the image data in the SD mode is read from the optical disc 18 and reproduced in step S11. The reproduced SD mode image data is written in the frame memory 3 and the process is terminated. As a result, an SD mode image is displayed on the monitor device 8.

If it is determined in step S10 that the mode is not the quick mode but no (N), the process branches to step S12 to determine whether or not the auto mode is set. If the user has instructed the auto mode, the determination is yes (Y) and the process proceeds to step S13. In step S13, the image data in the SD mode is read from the optical disc 18 and reproduced and written in the frame memory 3. As a result, an SD mode image is displayed on the monitor device 8.
Next, in step S14, the image data of the main image is read from the optical disc 18 and reproduced, and the frame memory 3 is overwritten with the reproduced image data of the main image, and the processing is ended. As a result, the image of the main image is displayed on the monitor device 8, and the quality of the displayed image is gradually improved over time (progressing function).

  Further, when it is determined NO (N) in step S12, it is the main mode, the process branches to step S15, the image data of the main image is read from the optical disc 18 and reproduced, and the reproduced main image is reproduced. The image data is written in the frame memory 3 and the processing is completed. As a result, the image of the main image is displayed on the monitor device 8.

By the way, although the fine mode described above is 1/5 compression and the normal mode is 1/16 compression, the present invention is not limited to this, and different compression ratios may be used.
Further, the compression processing of the image data may be performed by a 1/5 decimation circuit or a 1/16 decimation circuit.
In the above description, the recording medium is described as an optical disk. However, the present invention is not limited to this, and can be applied to a recording / reproducing apparatus including a recording medium such as a hard disk.

1 is a block diagram of an optical disc recording / reproducing apparatus to which a still image display method of the present invention is applied. FIG. It is a flowchart which shows operation | movement of the still image display method of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Scanner part 2 Video input part 3 Frame memory 4 Memory controller 5 CPU
6 Operation Unit 7 D / A Converter 8 Monitor Device 9 Printer Unit 10 Interface Block 11 Storage Unit 12 Interface 13 Raster / Block Conversion Circuit 14 Compression / Expansion Circuit 15 Memory 16 Buffer Memory 17 Disc Recording / Reproduction Unit 18 Optical Disc 19 System Controller 20 Operation unit 21 Display unit

Claims (4)

In a decoding device for decoding encoded image data,
The first encoded image data compressed by converting the image data to the first resolution is decoded to generate the first image data, and the image data is higher in resolution than the first resolution. Decoding means for decoding the second encoded image data that has been converted to the second resolution and compressed to generate second image data;
Determining means for determining whether to display the first image data, to display the first image data by replacing the first image data with the second image data, or to display the second image data;
Based on the determination result of the determination means, the decoding means is controlled, and the first image data generated by the decoding means is displayed on the display means while the entire first image data is displayed on the display means. 2 encoded image data is decoded, and the first image data displayed on the display means is rewritten and overwritten by one horizontal line while being replaced with the whole of the second image data. Control means for controlling the decoding means ;
Have
The second encoded image data is a first mode that is not compressed into the second encoded image data, and a second mode that is compressed into the second encoded image data at a first compression rate, Recording on the recording medium in the mode selected by the selection operation unit for selecting the mode among the third modes for compressing the second encoded image data at the second compression rate higher than the first compression rate Has been
The said control means is a decoding apparatus which controls the said decoding means when the said 2nd mode is selection-operated in the said selection operation part . In a decoding method for decoding encoded image data,
The first encoded image data compressed by converting the image data to the first resolution is decoded to generate the first image data, and the image data is higher in resolution than the first resolution. A decoding step of decoding the second encoded image data converted to the second resolution and compressed to generate second image data;
A determination step of determining whether to display the first image data, to display the first image data by replacing the first image data with the second image data, or to display the second image data;
Based on the determination result of the determination step, the decoding step is controlled, and the first image data generated by the decoding step is displayed on the display means while the entire first image data is displayed on the display means. The decoding step so that the encoded image data of 2 is decoded and the first image data displayed on the display means is replaced with the whole of the second image data while being rewritten one horizontal line at a time. And a control step for controlling
The second encoded image data is a first mode that is not compressed into the second encoded image data, and a second mode that is compressed into the second encoded image data at a first compression rate, Recording on a recording medium in a mode selected by a selection operation unit that selects a mode among the third modes for compressing the second encoded image data at a second compression rate higher than the first compression rate Has been
In the control step, a decoding method for controlling the decoding step when the second mode is selected in the selection operation unit . In a decoding device for decoding encoded image data,
First encoded image data obtained by compressing image data at a first compression rate is decoded to generate first image data, and second compression lower than the first compression rate is applied to the image data. Decoding means for decoding the second encoded image data compressed at a rate to generate second image data;
Determining means for determining whether to display the first image data, to display the first image data by replacing the first image data with the second image data, or to display the second image data;
Based on the determination result of the determination means, the decoding means is controlled, and the first image data generated by the decoding means is displayed on the display means while the entire first image data is displayed on the display means. The decoded image data is decoded so that the first image data displayed on the display means is replaced by the entire second image data while being rewritten one horizontal line at a time. Control means for controlling the means, and
The second encoded image data is a first mode that is not compressed into the second encoded image data, and a second mode that is compressed into the second encoded image data at a first compression rate, Recording on a recording medium in a mode selected by a selection operation unit that selects a mode among the third modes for compressing the second encoded image data at a second compression rate higher than the first compression rate Has been
The said control means is a decoding apparatus which controls the said decoding means when the said 2nd mode is selection-operated in the said selection operation part . In a decoding method for decoding encoded image data,
First encoded image data obtained by compressing image data at a first compression rate is decoded to generate first image data, and second compression lower than the first compression rate is applied to the image data. A decoding step of decoding second encoded image data compressed at a rate to generate second image data;
A determination step of determining whether to display the first image data, to display the first image data by replacing the first image data with the second image data, or to display the second image data;
Based on the determination result of the determination step, the decoding step is controlled, and the first image data generated by the decoding step is displayed on the display means while the entire first image data is displayed on the display means. The decoding step so that the encoded image data of 2 is decoded and the first image data displayed on the display means is replaced with the whole of the second image data while being rewritten one horizontal line at a time. And a control step for controlling
The second encoded image data is a first mode that is not compressed into the second encoded image data, and a second mode that is compressed into the second encoded image data at a first compression rate, Recording on a recording medium in a mode selected by a selection operation unit that selects a mode among the third modes for compressing the second encoded image data at a second compression rate higher than the first compression rate Has been
In the control step, a decoding method for controlling the decoding step when the second mode is selected in the selection operation unit .

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