JP3521436B2 - Image compression device and image reproduction device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image compression device and an image reproduction device, and more particularly to an image compression device for compressing image data recorded on a recording medium such as a CD-ROM or a hard disk, and communication from the image compression device. Image data transmitted through the line or C recorded in the image compression device
The present invention relates to an image reproducing device used when reproducing image data from a recording medium such as a D-ROM or a hard disk.

[0002]

2. Description of the Related Art An image reproducing device is a device for reading a code of a compressed image and displaying it on a display device. The image data used in such a device is created using an image compression device.

Next, a conventional image compression apparatus and image reproduction apparatus will be described with reference to the drawings.

FIG. 7 is a block diagram of a conventional image compression apparatus.

The CPU 60 executes a program stored in the ROMB 64 to control the entire device. The processing of the image reproducing apparatus is designated by the input from the keyboard 62. The video signal from the VTR 67 is A by the A / D converter 66.
A / D converted, separated into a luminance signal and a color difference signal by a Y / C separator 65, and compression-coded by a video encoding unit B68,
It is stored in the RAM 61. The compressed image data is sent by the transmission unit 69.
Is transmitted to the communication line. In addition, the hard disk 63
The data of the compressed image encoded by the video encoding unit B68 is recorded in.

FIG. 8 is a block diagram of a conventional image reproducing apparatus.

The CPU 70 executes a program stored in the ROMB 74 to control the entire device. The processing of the image reproducing apparatus is designated by the input from the keyboard 72. The compressed image data is received from the reception unit 79, and RA
Store in M71. The image data is decoded by the video decoding unit B78, the luminance signal and the color difference signal are combined by the Y / C combiner 75, and converted into the video signal by the D / A converter 76,
Displayed on the display 77. Further, the compressed image data received from the receiving unit 79 is recorded on the hard disk 73, and the compressed image data is read from the hard disk 73 and reproduced.

[0008]

The conventional image reproducing apparatus described above is stored in the ROMB 64 depending on the performance of the apparatus such as the CPU 60, the A / D converter 66, the Y / C separator 65 and the size of the compression code of the image. The executed program may run slowly. 1 for image compression devices with slow processing speed
The frame image processing time becomes long and the frame interval becomes large. When a compressed image created by such a device is played back, there is a problem in that the motion of a moving image becomes unsmooth and looks unnatural.

Further, the image reproducing apparatus includes a CPU 70, D /
The execution speed of the program stored in the ROMB 74 may be slow depending on the performance of devices such as the A converter 76 and the Y / C combiner 75, the size of the compression code of the image, and the like. In an image reproducing apparatus having a slow processing speed, the image processing time for one frame becomes long and the frame interval becomes large. When a compressed image is reproduced by such a device, there is a problem in that the motion of a moving image becomes unsmooth and looks unnatural.

[0010]

The image compression apparatus of the present invention refers to a means for dividing an original image into a plurality of image blocks and a prediction table defining a block thinning rate of an image optimum for a reproduction speed. and means for changing the block thinning rate of image in accordance with the designated reproduction speed Te, removed from the block thinning rate thus the plurality of image blocks
And a means for compressing only a predetermined image block .

Further, the image compression apparatus of the present invention is an original image
Compressed by compressing multiple image blocks
Means for inputting an image, and means for changing the block thinning rate of image according to the reference reproduction speed designated by the prediction table defining the block thinning ratio of optimal image in an image reproduction speed, said block If the block thinning rate of the compressed image as compared thinning rate and the block thinning rate of the compressed image is low, extraction block thinning rate thus from the compressed images referred from the prediction table
And a means for reproducing only a predetermined compressed image block .

[0012]

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

FIG. 1 is a block diagram showing an embodiment of an image compression apparatus according to the present invention.

The CPU 1 executes a program stored in the ROMA 5 to control the entire device. The processing of the image reproducing apparatus is designated by the input from the keyboard 3. VT
The video signal from R8 is A / D converted by the A / D converter 7, and separated into a luminance signal and a color difference signal by the Y / C separator 6,
It is compression-encoded by the video encoding unit A9 and stored in the RAM 2. The compressed image data is transmitted from the transmitter 10 to the communication line. Also, the compressed image data encoded by the video encoding unit 9 is recorded on the hard disk 4. A prediction table for predicting thinning for each reproduction speed is stored in the ROM A5, images are thinned according to the optimum block thinning rate from the prediction table, and are encoded by the video encoding unit A9.

FIG. 2 is a block diagram showing an embodiment of the image reproducing apparatus according to the present invention.

The CPU 20 executes a program stored in the ROMA 24 to control the entire device. The processing of the image reproducing apparatus is designated by the input from the keyboard 22. The compressed image data is received from the receiving unit 29, and the RAM is
21. The image data is decoded by the video decoding unit 28, the luminance signal and the color difference signal are combined by the Y / C combiner 25, converted into the video signal by the D / A converter 26, and displayed on the display 27. The compressed image data received from the receiving unit 29 is recorded in the hard disk 23, and the compressed image data is read from the hard disk 23 and reproduced. A prediction table for predicting thinning for each reproduction speed is stored in the ROM A24, and images are thinned according to the optimum block thinning rate from the prediction table and decoded by the video decoding unit A28.

Next, image thinning in the present embodiment will be described with reference to Tables 1 to 4.

[0018]

[Table 1]

[0019]

[Table 2]

[0020]

[Table 3]

[0021]

[Table 4]

As shown in Tables 1 to 4, the original image is divided into several blocks and the blocks are thinned to reduce the amount of image data. Table 1 is a table of original images. As shown in Table 1, when the original image is divided into blocks of 8 dots × 8 dots, when the size of the original image is 240 dots × 240 dots, it is divided into 30 blocks × 30 blocks. Numbering this block from the upper left is 1, 2, 3 ...
There will be 900 blocks. When the block thinning ratio is 1/1 (no thinning) in this image, as shown in Table 2, blocks are taken from the upper left as 1, 2, 3 ... 31, 32, 33 ... Decrypt. In this case, the number of blocks does not change, so the processing speed does not change. Further, when the block thinning rate is 1/2, as shown in Table 3, it is considered that the images of the two adjacent blocks on the left and right are equal to each other, from the upper left, 1, 3, 5 ... 31, 33, 35.
.. and blocks are extracted and encoded / decoded. In this case, the number of blocks is reduced to 1/2, and the processing speed is increased. Further, when the block thinning rate is 1/4, as shown in Table 4, it is considered that the images of the four blocks that are adjacent to each other on the left, right, top and bottom are equal, and from the upper left 1, 3, 5 ... 61, 6
, 65 ... Are taken out and encoded / decoded. In this case, the number of blocks is reduced to 1/4 and the processing speed is further increased.

The processing in the case of changing the thinning-out of an image according to the processing speed with the above configuration will be described for each processing.

FIG. 3 is a flowchart for controlling image compression in the image compression apparatus of this embodiment, FIG. 4 is a flowchart for controlling image reproduction in the image reproduction apparatus of this embodiment, and FIG. 5 is image compression of this embodiment. Diagram of coded data when thinning processing is performed in the device and the image reproduction device,
FIG. 6 is a configuration diagram of a prediction table when determining the block thinning rate in the image compression apparatus and the image reproduction apparatus of this embodiment.

(1) Processing on the image compression side When the image compression apparatus is started as shown in FIG. 3, ON / OFF of transmission is designated from the input of the keyboard 22 (step 20), and the input of the keyboard 22 is performed. The number of frames to be reproduced, the reproduction speed and the file name are input (step 21), the data of the matching block thinning rate is extracted from the reproduction speed and the prediction table recorded in the ROMA 5 (step 22), and the video signal of the VTR 8 is obtained. A / D
The Y / C separator 6 is converted by the converter 7 (step 23).
Is separated into a luminance signal and a color difference signal (step 24), the data of the thinned block is extracted in accordance with the block thinning rate of the current frame (step 25), the block data is compression-encoded by the video encoder A9, and the RAM 2 (Step 26). Next, it is judged whether or not the transmission is designated to be ON (step 27), and if so, the code of the RAM 2 is sent to the communication line by the transmitter 10 (step 28). Otherwise, go to step 29. Next, it is judged whether or not the block is the final block, and if not, the process returns to step 25. If yes, RA
The code of M2 is recorded on the hard disk 4 (step 3).
0). Next, it is judged whether or not the frame is the final frame (step 31), and if not so, the process returns to step 23, and if so, the process ends. (2) Processing on the image reproducing side When the image reproducing apparatus is started as shown in FIG. 4, ON / OFF of reception is designated by the input of the keyboard 22 (step 40), and a frame is reproduced by the input of the keyboard 22. The number, the reproduction speed, and the file name are input (step 41), the data of the matching block thinning rate is extracted from the reproduction speed and the prediction table recorded in the ROMA 24 (step 42), and the designation of reception is ON. It is determined whether or not (step 43), and if so, the compressed image data is received from the communication line from the receiving unit 29 and stored in the RAM 21 (step 44), and the compressed image data stored in the RAM 21 is stored in the hard disk. 23 (step 45). If not, read a file of compressed image data from the hard disk 23 and execute R
It is stored in the AM 21 (step 46) and the process proceeds to step 47. Next, the block thinning rate from the prediction table of the current frame is compared with the block thinning rate of the compressed data to determine whether the block thinning rate from the prediction table is high (step 47). The code of the thinned block is extracted in accordance with the block thinning rate (step 48). For example, when the block thinning rate of the prediction table is 1/2 and the block thinning rate of the compression code is 1/1, every other block is taken out as shown in Table 3. If not, the block code is extracted without thinning (step 49). Next, the code of the block is decoded by the video decoding unit A28 (step 50), it is judged whether or not it is the final block (step 51), and if not so, the process returns to step 47. If so, Y /
The C synthesizing unit 25 synthesizes the luminance signal and the color difference signal (step 52), the D / A converter 26 converts the synthesized signal into a video signal (step 53), and the image is displayed on the display 27 (step 54). ). Next, it is judged whether or not it is the last frame (step 55), and if not, step 4
Return to 3, and if so, end the process.

The code data as shown in FIG.
It includes (1) a portion for setting a block thinning rate for each frame, and (2) a portion for a compression code for each block according to the block thinning rate. RA set in this way
It is stored in M2 or the RAM 21. In the example of FIG. 5, “the first frame is a code of 1/2 block thinning rate, 2
The frame number is the code of the block thinning rate of 1/4 ... "
Is set.

Further, as shown in FIG. 6, the prediction table includes (1) a portion for setting the reproduction speed, (2) a portion for setting the number of block thinning rates set for each frame, and (3) ) It includes the part to set the block thinning rate. ROMA5 or ROM set in this way
It is stored in A24. In the example of FIG. 7, "the playback speed is 0.1
If it is less than frames / second, the first frame has a block thinning rate of 1/4, the second frame has a block thinning rate of 1/4, and so on. Also, the playback speed is 0.1
In the case of 0.5 frames / second, the first frame has a block thinning rate of 1/1, the second frame has a block thinning rate of 1/2, and the third frame has a block thinning rate of 1/2. repetition. Is set.

[0028]

As described above, the image compressing apparatus and the image reproducing apparatus of the present invention, when reproducing the image data of the block thinning rate lower than the block thinning rate adapted to the reproducing speed, thin the image and reproduce. By doing so, it is possible to reproduce at a uniform speed.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an image compression apparatus according to the present invention.

FIG. 2 is a block diagram showing an embodiment of an image reproducing apparatus according to the present invention.

FIG. 3 is a flowchart for controlling image compression in the image compression apparatus in FIG.

FIG. 4 is a flowchart for controlling image reproduction in the image reproduction device of FIG.

FIG. 5 is a configuration diagram of code data when performing a thinning process in the image compression apparatus and the image reproduction apparatus of the present embodiment.

FIG. 6 is a configuration diagram of a prediction table when determining a block thinning rate in the image compression apparatus and the image reproduction apparatus of the present embodiment.

FIG. 7 is a block diagram of a conventional image compression apparatus.

FIG. 8 is a block diagram of a conventional image reproducing device.

[Explanation of symbols]

1 CPU 2 RAM 3 keyboard 4 hard disk 5 ROMA 6 Y / C separator 7 A / D converter 8 VTR 9 Video code part A 10 Transmitter 20 CPU 21 RAM 22 keyboard 23 hard disk 24 ROMA 25 Y / C synthesizer 26 D / A converter 27 display 28 Video decoding unit A 29 Receiver 60 CPU 61 RAM 62 keyboard 63 hard disk 64 ROMB 65 Y / C separator 66 A / D converter 67 VTR 68 Video coding section B 69 Transmitter 70 CPU 71 RAM 72 keyboard 73 Hard Disk 74 ROMB 75 Y / C synthesizer 76 D / A converter 77 display 78 Video decoding unit B 79 Receiver

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Claims (2)

(57) [Claims] 1. An original image is divided into a plurality of image blocks.
Means, and means for changing the block thinning rate of image in accordance with the optimum reproducing speed block thinning ratio specified by referring to the prediction table defining the image to the reproduction speed, before
Or the serial block thinning rate thus the plurality of image blocks
And a means for compressing only a predetermined image block extracted from the image compression apparatus. 2. A plurality of image blocks divided from an original image.
The input means for inputting compressed images respectively, and the prediction table that defines the optimum image block thinning rate for the image playback speed are referenced, and the image block thinning rate is set according to the specified playback speed. and means for changing, by comparing the block thinning rate of the compressed image and the block thinning rate
Wherein when the block thinning rate of the compressed image is low, thus before the block thinning rate is referenced from said pre <br/> measurement table
Only the specified compressed image block extracted from the compressed image
And a means for reproducing the image.