JP2003087798A - Apparatus and method for moving image compression - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus and method for moving image compression by which a moving image is compressed without a loss and by high compressibility. SOLUTION: Moving image data consisting of a plurality of frame pictures are stored in a memory 11. Under control by a control part 12, a data string creation part 13 extracts luminance data of a pixel at a prescribed string in the order of horizontal scanning from each stored frame picture, arranges the extracted luminance data in the order of frames, and prepares a moving image data string by arranging the luminance data string prepared with respect to all the strings of the frame pictures in the order of vertical scanning in addition. The prepared moving image data are compressed by a PNG compression part 14 consisting of an LZ77 compression part 141 for performing the PNG compression and a Huffman coding part 142 for performing Huffman coding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving picture compression apparatus and method for compressing moving picture data using the PNG (Portable Network Graphics) method.

[0002]

2. Description of the Related Art An optical fiber with a line capacity of G (giga) bytes is drawn to individual homes, and 2M is required when moving.
Even in the broadband era, in which the 4th generation mobile phones in which a (mega) bps (bit per second) band is secured, moving image compression is an indispensable technology.

An operator who draws an optical fiber to each home determines the line capacity by assuming a charge that the user can bear. In addition, we will pursue cost performance by adopting the best-effort method (a method that reduces the line capacity according to the congestion when the line is crowded) as the data transmission method. Therefore, the line capacity of an optical fiber drawn to an individual home is limited to a certain size. Therefore, even if the optical fiber has a data transmission capacity of T (tera) bytes, it can be expected that the capacity of the optical fiber drawn to the home will be about 100 Mbps for economical reasons.

On the other hand, the amount of data of a moving image transmitted is 700 × 525 × 30 (frame / s) in NTSC.
× 8 (bit) × 3 (RGB) = 264 Mbps. Moreover, in HDTV, it reaches 1.3 Gbps which is five times as large as this. Therefore, this amount of data is 100 Mb
In order to transmit with a line capacity of ps, a moving image compression system having a compression rate of about 1/3 to 1/13 is required.

In addition, the amount of data received during high-speed movement is at least 2
When it is assumed that a moving image of the same level as NTSC is displayed on the screen of 160 × 120 pixels of the 4th generation mobile phone which becomes Mbps, the data amount is 160 × 120 × 30.
× 3 = 13 Mbps. This data amount is 2 Mbps
In order to transmit with the line capacity of, a moving image compression method having a compression rate of 1/7 or more is required.

[0006]

In a broadband environment where pay broadcasting is the mainstream, the user can freely select and watch his favorite program. Under such an environment, it is considered that the user cannot be satisfied when the image quality of the selected program is equal to or lower than the current TV broadcast. Therefore, it can be said that the image quality must be good as the user pays the monthly usage fee.

For the reasons described above, the compression method required in the broadband era is lossless compression that maintains the quality of the original image, and the compression ratio for natural images satisfies 1/10 to 1/20. Must be something that

On the other hand, MPEG (MPEG-1, MPEG-2, MP) is used as a moving image compression method currently used.
EG-4), Motion JPEG, and Motion JPEG 2000 which employs discrete wavelet transform instead of DCT (discrete cosine transform). In these systems, a compression ratio of 1/20 is sufficient. However, there is a problem that compression in MPEG is not lossless. Also, Moion JPEG / Mo
tionJPEG2000 is lossless, but 1/2
There is a problem that only a moderate compression rate can be obtained.

Further, PNG and GIF (Graphics Interchange Format) are available as lossless compression methods for color still images. But,
The compression ratio of the natural image in these methods is 1 / 1.5 to
It is about 1/3. Further, the GIF has a drawback that it can support only 256 colors.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a moving image compression apparatus and method capable of compressing a moving image with a lossless and high compression rate.

[0011]

In order to solve the above-mentioned problems, a moving picture compression apparatus according to the present invention comprises a storage means for storing a moving picture composed of a plurality of frame images,
Luminance data of all columns of a frame image is created by extracting luminance data of pixels in a predetermined column from each stored frame image in the horizontal scanning order and arranging the luminance data in frame order. A data string creating means for creating a moving image data string by further arranging the columns in the vertical scanning order; and a compression / encoding means for performing compression / encoding processing of the moving image data string using the PNG method. Characterize.

Further, the moving image compression apparatus according to the present invention stores the moving image composed of a plurality of frame images and the luminance data of the pixel at a predetermined position from each of the stored frame images. A data string creating unit that creates a brightness data string by arranging the brightness data in frame order, and further creates a moving image data string by arranging the brightness data strings created for all pixel positions of the frame image in the scanning order. , The PNG method is used to compress and encode the moving image data sequence.
And an encoding means.

Further, the moving picture compression apparatus according to the present invention comprises a judging means for judging a reference frame picture serving as a reference for moving picture compression from a plurality of frame pictures forming the moving picture, and the reference frame picture. And a second storage means for storing a frame image other than the reference frame image, and a comparison means for calculating comparison information between the reference frame image and a frame image other than the reference frame image. And a third storage unit that stores the calculated comparison information, a data creating unit that creates a moving image data sequence based on the reference frame image and the calculated comparison information, and the moving image using the PNG method. Image data string compression
A compression / encoding means for performing encoding processing is provided.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

<First Embodiment> FIG. 1 is a block diagram showing the arrangement of a moving picture compression apparatus according to the first embodiment of the present invention. The memory 11 has a function as a storage unit that stores a moving image composed of a plurality of frame images obtained as image signals. Further, a synchronization signal indicating the separation state of images is input to the control unit 12 connected to the memory 11. The control unit 12 further includes a data string creating unit 13 for creating a new moving image data string and a PNG for compressing / encoding the created data string using the PNG method.
It is connected to the compression unit 14.

Then, the controller 12 controls the data string generator 1
3 and the PNG compression unit 14 are controlled. That is, the control unit 12 uses the input synchronization signal as a reference,
It has a function of calling from the memory 11 and passing it to the data string creating unit 13 in order to create the brightness data of the same line of each frame as a data string for each line. The data string created by the data string creating unit 13 is transferred to the PNG compressing unit 1
It also has the function of inputting to 4.

The PNG compressor 14 is an LZ77 compression unit 14.
1 and a Huffman coding unit 142. FIG. 2 is a diagram for explaining a compression method performed by the PNG compression unit 14. The compression method performed by the LZ77 compression unit 141 is A. Lempel and J. Z
This is a method of compressing an original data string that is not compressed by the LZ77 compression 21 developed by iv. The Huffman coding unit 142 performs Huffman coding 22 on the compressed data string. The Huffman coding 22 is a method of checking the frequency of occurrence of each pixel value, assigning a short code to each pixel value in the order of high frequency of occurrence, and reducing the overall code amount. This makes it possible to create compressed / encoded data.

The decompression / decoding procedure is the reverse of the compression procedure. That is, the Huffman decoding 23 is performed on the compressed data string. Then LZ77
The decompression 24 is performed so that the original data string can be restored losslessly. The compression method combining LZ77 and Huffman coding as described above is based on Deflate / Infl.
Called ate compression.

Here, the compression procedure in the LZ77 compression section 141 and the coding procedure in the Huffman coding section 142 will be described with reference to an example. For example, a luminance data string "A" of an image composed of two types of pixel values A and B
A case of compressing "BBABBA" will be described. LZ77
In compression, first, the luminance data string “ABBABBA” is transformed into “ABB (3,4)”. Where (3
4) means to go back 3 characters and copy 4 characters. Next, this character string is transformed into "ABBc4 (3)". Then, Huffman coding is performed on this character string by the operation of the Huffman coding unit 142.

As an example, here, B = 0 and A = 1.
0, c4 = 11, and (3) = 0 are assigned. At this time, after c4, which indicates the number of characters to be copied, the copy position is always (3), and therefore B = 0 and (3) = 0 can be distinguished from each other. The compression / encoding result in this case is “1000110”. This is P
This is a compression method using NG.

That is, PNG is a compression method capable of compressing an image at a high compression ratio when used in a line drawing or an animation image in which the same brightness values are continuously arranged or the same brightness pattern appears a plurality of times. For example, the compression rate when compressing a line drawing still image by the PNG method is 1
It ranges from / 50 to 1/70. Further, since CPU power is not required as compared with orthogonal transform such as DCT or wavelet transform, it is possible to perform compression / encoding of an image having a large screen or a high frame rate.

On the other hand, the weak point of PNG is that the compression rate when compressed is low for an image in which the same luminance value does not appear consecutively or a natural image in which pixels having different luminance values are randomly arranged. is there. Therefore, in this embodiment, in order to compensate for this weak point and adapt the PNG to a moving image, moving image data composed of N frames is not first captured and sequentially compressed for each frame, but for each line from each frame. We propose a method of sampling and compressing with PNG.

FIG. 3 is a flow chart for explaining the image signal compression procedure according to the embodiment. The control unit 12 designates the line number L of the image data of each frame stored in the memory 11 on the basis of the input synchronizing signal. Initially, the number of lines L is designated as 1 (step S31). Then, the control unit 12 determines whether the designated line number L is larger than the total line number of the frame (step S32). As a result, when the designated line number L is larger than the frame line number (YES),
The compression / encoding ends. On the other hand, the specified number of lines L
Is within the number of lines in the frame (NO), the control unit 12
Calls the luminance data of the specified line from 1 frame to N frames and passes the data string to the PNG compression unit 14 (step S33).

FIG. 4 is a diagram for explaining a method of reading image data in the same embodiment. As described above, the memory 11 is loaded with all moving image data from one frame to N frames. Then, the control unit 12 first calls the data of the first line 41 of the first frame, then the first line 42 of the second frame, and further the first line 43 of the third frame. And finally, the first line 4 of the Nth frame
4 data strings are called, all of these data strings are converted into one data string, and then PNG compression is performed. After this, the second line 45 of the first frame is further called, and the processing is performed in the same procedure thereafter.

The called luminance data string is compressed by the LZ77 compression section 141 in the PNG compression section 14 (step S34). Here, the compression procedure according to the present embodiment will be specifically described by taking a case of a moving image of 10 frames in which image data of one frame has a size of 640 × 480 pixels. In this case, the image data of the first line of the first frame is "ABCDRFG ..."
It is assumed that 40 pixel values are lined up.

Here, in a moving image from 1 frame to 10 frames, if there is no motion in the image or if it is assumed that there is no change in luminance, the first line of the second frame is also "ABCDEFG ...", 3 The first line of the frame also has “ABCDEFG ...”, and the luminance level of the first line of the tenth frame also has “ABCDEFG ...”. When these data are compressed by the LZ77 compression unit 131, “AB
CDEFG ... (640,5760) ". In addition,
(640, 5760) means “return 640 characters in the character string ABCDEFG ... And copy 640 × 9 (= 5760) characters”. In addition, "ABCDEF
If the pixels having the same luminance value are continuous, the portion of "G ..." Is further compressed in the same manner.

Further, this character string is changed to "ABCDEFG ...
・ C5760 (640) ”is transformed. The Huffman coding unit 142 performs Huffman coding on this character string (step S35). Here, as an example of encoding, c5760 = 0, (640) = 0, A = a, B
= B, C = c, D = d, E = e, F = f, G = g. In this case, "ABCDEFG ... c5760
(640) ”is encoded as“ abcdefg ... 00 ”.

Assuming that the compression rate by PNG is 1/2, the data rate in 10 frames is 1 if the moving part is 10% of the entire screen.
(Frame) x 1/2 + 9 (frame) x 0.1 (moving part) x 1/2, the compression rate is 0.95 / 10 = about 1
It becomes / 10. Also, in the case of a moving image in which continuous still images have no movement or change in the image, 1 × 1/2
Therefore, the compression rate in 10 frames becomes 1/20.

The compression rate at this time is 1/10 in 10 frames if the moving portion is 10% of the entire screen. Further, in the case of a moving image in which a continuous still image has no movement or change in the image at all, the compression rate can be increased to 1/20.

After the compression of the first line is completed, the second line is designated next (step S35). And step S
Returning to step 32, the image data is called, compressed and encoded in the same manner. The compression work does not have to be started at the time when all the frame data is read. For example, when one frame image is read, the first line of the frame may be designated and called at the same time. Good.

As described above, in the first embodiment, the storage means (memory 11) for storing a moving image composed of a plurality of frame images and the brightness of the pixels in a predetermined column from each of the stored frame images. Luminance data strings are created by extracting data in the horizontal scanning order and arranging the brightness data in frame order, and moving image data strings are created by arranging the brightness data strings created for all the columns of the frame image in the vertical scanning order. Since the data string creating means (data string creating unit 13) and the compression / encoding unit (PNG compressing unit 14) for compressing / encoding the moving image data string using the PNG method are provided, The effect of compressing a moving image at a lossless and high compression rate, which cannot be obtained by the conventional compression method, can be obtained at the same time.

<Second Embodiment> Next, a second embodiment of the present invention will be described with reference to the drawings. Figure 5
It is a block diagram which shows the structure of the moving image compression apparatus by 2nd Embodiment. Each unit shown in FIG. 5 has the same configuration and operation as each unit shown in FIG. 1 except for the data string creating unit 51. The data string creation unit 51 in FIG.
Unlike the data creating unit 13 in the first embodiment, a data string is not created for each line, but a data string is created for each pixel in the time axis direction.

FIG. 6 is a flow chart for explaining the operation procedure of the moving picture compression apparatus according to the embodiment shown in FIG. First, the first pixel of one frame is designated (step S61). Next, the pixel L at the specified position
Is determined to exceed the total number of pixels in the frame (step S62). As a result, if all the pixels are recalled beyond the total number of pixels in the frame (YES), compression / compression
The encoding process ends. On the other hand, if the specified number of pixels does not exceed the total number of pixels in the frame (NO), the brightness levels of the specified pixels from one frame to N frames are called (step S63). Initially, the first pixel of all frames is called.

FIG. 7 is a diagram for explaining the calling of pixels in the same embodiment. As described above, first, all moving image data from one frame to N frames are read. Therefore, the data of the first pixel of the first frame is called, and then the first pixel of the second frame, 3
In the order of the 1st pixel of the frame, the 1st pixel of the Nth frame
Call the pixel data. The second pixel of each frame is called in the same procedure.

The operation procedure up to step S62 when N = 10 will be specifically described. For example, a moving image that does not move from 1 frame to 10 frames,
If the moving image has no brightness change, the image data of the first pixel in the first frame is A, and the first pixel in the second frame is A, 1
The brightness level of the first pixel in the 0th frame is also A. When these data are compressed by the LZ77 compression unit 141, "A
c9 (1) ”(step S64).

For this character string, the Huffman encoder 13
Huffman coding is performed by 2 (step S6).
5). As an example, c9 = 0, (1) = 0, and A = a are assigned. At this time, "AAAAAAAAAAA" is "a
00 "can be compressed. Similarly, the designated pixel is increased by one (step S66). When the brightness value of the second pixel is B and the brightness value of the third pixel is C, the brightness data string of all frame images is “AAAAAAAAAA.
ABBBBBBBBBBBCCCCCCCCCC ... ". In this case, in the compression / encoding described above, B =
When b and C = c are assigned, the original luminance data string becomes “a
00b00c00 ... ”.

As described above, in the second embodiment, the storage means (memory 11) for storing a moving image composed of a plurality of frame images and the luminance of the pixel at a predetermined position from each of the stored frame images. Luminance data strings are created by extracting data and arranging the brightness data in frame order, and moving image data strings are created by arranging the brightness data strings created for all pixel positions of the frame image in the scanning order. A data string creating unit (data string creating unit 51) and a compression / encoding unit (P) for compressing / encoding the moving image data string using the PNG method.
Since the NG compression unit 14) is provided, the effect of compressing a moving image at a lossless and high compression rate, which cannot be obtained by the conventional compression method, can be obtained at the same time, as in the first embodiment.

<Third Embodiment> FIG. 8 is a block diagram showing the arrangement of a moving picture compression apparatus according to the third embodiment of the present invention. In FIG. 8, the determination unit 81 determines whether the input image signal is an S frame which is a reference frame or a D frame other than that. Judgment unit 81
Is connected to a memory 82 for storing frame images. FIG. 9 is a diagram for explaining the division of frames in the same embodiment. For example, in a moving image composed of N frames, the first first frame 91 is used as a reference frame, and this is called an S frame. Also, the second frame 92
The following is a D frame. In the D frame, the second frame 92 is referred to as a D ₁ frame, the third frame 93 is referred to as a D ₂ frame, and the Nth frame 93 is referred to as a D _N-1 frame.

The input image data is stored in the memory 82. The memory 82 is further composed of two memories, and the S frame information is stored in the S frame memory 821.
Further, the D frame information is divided and stored in the D frame memory 822. In addition, the memory 82 further includes a control unit 83.
Is connected to the comparison unit 84. In the comparison unit 84, the brightness values are compared for each pixel at the same position in the S frame and the D frame, and the comparison result is used as comparison information.
It is stored in the storage unit 85 connected to the comparison unit 84.

Here, in the present embodiment, the comparison unit 84 is
Comparing information of two types of brightness change flags to be generated for the pixel at the same position in the S frame, which is the reference frame, and the D frame, which is a frame image other than the reference frame image, for the same brightness value and the different brightness value Shall be calculated as On the other hand, the storage unit 85 is composed of two storage units, and the image data storage unit 851 stores the image data of the S frame and the D frame as they are.
And a brightness change flag storage unit 852 that stores comparison information.

The storage unit 85 is further connected to the control unit 83, the data string creating unit 86, and the PNG compression unit 14.
The data string creation unit 86 creates a moving image data string based on the information stored in the image data storage unit 851 and the brightness change flag storage unit 852 in the storage unit 85. The sync signal for the image signal is input to the control unit 83.

FIG. 10 is a flow chart for explaining the operation procedure of the moving picture compression apparatus shown in FIG. When an image signal is input, the determination unit 81 first determines whether the image signal is an S frame or a D frame (step S101). As a result, when it is determined that the frame is the S frame (YES), the image data is stored in the S frame memory 821 (step S10).
2). On the other hand, if it is determined that the frame is not the S frame (N
O), the frame is determined to be the D frame, and the image data is stored in the D frame memory 822 (step S103).

Next, the comparison unit 84 calls for comparing the brightness values of the pixels at the same position in the S frame and the D frame (step S104). Then, the comparison unit 84
It is determined whether the difference between the two is 0 (step S10).
5). As a result, when the difference between the two is 0 (YES), the comparison unit 84 generates the brightness change flag 0 (step S1).
06), the data is stored in the brightness change flag storage unit 852 in the storage unit 85 (step S110). Also,
When the difference between the two is not 0 (NO), the brightness change flag 1
Is generated (step S107) and stored in the brightness change flag storage part 852 in the storage part 85 (step S10).
8). In addition, the image data storage unit 851 stores the brightness data of the pixel at the position of the brightness change flag 1 (step S109). Further, the control unit 83 causes the S frame memory 821 to output the S frame image information, and causes the S frame image information to be input to the image data storage unit 851 (step S110).

The last in the memory unit 85, S frame image data, the change in D ₁ frame images Furagubitsuto, luminance level of the luminance change pixels D ₁ frame images, · · ·, D _N-1 changes the frame image Furagubitsuto, D _The data is called in the order of the brightness level of the brightness changing pixels of the _N-1 frame image, and the PNG compressing unit 13 compresses the data string by the procedure described above (step S111) and further encodes it (step S112).

FIG. 11 is a diagram for explaining an example of the data structure of the image data in the third embodiment. The image data includes S frame image data, which is a data string in which the luminance data of all pixels in the reference frame image are arranged in the scanning order, and a data string in which luminance change flags are arranged in the scanning order for all pixels in the frame images other than the reference frame image. change flag of a D ₁ frame image, the luminance data of the D ₁ frame image is the luminance data in the frame image in the case indicating a luminance change flag reference frame image and the same luminance value, ..., the D _N-1 frame image Change flag, D
_N-1 frame images are arranged in the order of luminance data.

Here, the compression procedure in this embodiment will be described.
A specific description will be made assuming that N = 10 and the size of one frame is 640 × 480 pixels. In this case, it is assumed that there is no movement or continuous brightness change between two consecutive frames. Then, the brightness data of each frame is scanned in the order of “AB
CDEGG ... ”. At this time, the total number of data is 640 × 480 = 307200. Similarly, the brightness data of the second frame is also "ABCDEFG ...
・ ”, And the number of data is 307,200.

When the difference in luminance level between the pixels in the first frame and the pixel in the second frame is calculated, the difference is 0 because it is assumed that they are the same image, and the image data in the second frame has 307200 luminance change flags 0. It is composed of 0 luminance data. That is, in the form of data, "A
BCDEFG ... 00000 ... 0 ". When this is compressed by the LZ77 compression unit 131, "ABCDEFG
... 0c307199 (1) ".

Further, the "ABCDEFG ..." Part can be similarly compressed when the pixels having the same pixel value are continuous. On the other hand, the Huffman coding unit 132 performs Huffman coding. As an example,
c307199 = 0, (1) = 0, A = a, B = b, C
= C, D = d, E = e, F = f, G = g.
In this case, "ABCDEFG ... 0c307199
The data string “(1)” can be compressed into the form “abcdefg ... 00”.

As described above, in the third embodiment, the judgment means (judgment unit 81) for judging the reference frame image which becomes the reference for the moving image compression from the plurality of frame images forming the moving image. A first storage means (S frame memory 821) for storing the reference frame image, a second storage means (D frame memory 822) for storing a frame image other than the reference frame image, the reference frame image and the reference frame A comparison unit (comparison unit 84) that calculates comparison information with a frame image other than the image, and a third storage unit (luminance change flag storage unit 85) that stores the calculated comparison information.
2), data creating means (data string creating unit 86) for creating a moving image data string based on the reference frame image and the calculated comparison information, and compression / coding of the moving image data string using the PNG method. Compression / encoding means (P
Since the NG compression unit 14) is provided, it is possible to perform compression that simultaneously satisfies the lossless and high compression ratio, which cannot be obtained by the conventional compression method, as in the above-described embodiment.

As described above, in the present invention, the PNG is
By adding compression in the time axis direction to the compression method, the compression ratio for natural moving images with little motion or images without motion is set to 1
We have proposed a technology to increase to / 10 to 1/20. At this time, in the frame image, when there is no brightness change in the time axis direction, lines having the same brightness appear the same number of times as the number of frames, so that the compression rate can be further increased. Further, an animation image having a relatively large number of uniform brightness portions or a moving image in which characters or the like are displayed on a background having a single brightness can be compressed to about 1/500 of the original image data. .

Further, according to the present invention, MPEG and M
DCT or Moti adopted by motionJPEG
Compared to the wavelet conversion adopted by onJPEG2000, the load on the CPU is lighter and the motion guarantee that requires high CPU power is not adopted, so it is effective for compression / decoding of images with a large screen or high frame rate. Is obtained.

In the above-described embodiment, the moving image is described as being composed of N frames. For example, when reproducing at 30 frames per second, for a moving image of 10 minutes, 30 × 60 × 10 = 18000. It can also be a frame.
Therefore, in this case, if N = 18000, an enormous memory is required, and therefore, compression / encoding may be performed in units of 30 frames, for example. Note that this unit may be variable according to a user's instruction.

Even when the present invention is applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), an apparatus including one device (for example, a copying machine, (For example, a facsimile machine).

Further, an object of the present invention is to supply a recording medium (or storage medium) recording a program code of software for realizing the functions of the above-described embodiment to a system or apparatus, and to supply a computer of the system or apparatus ( Alternatively, the CPU or MPU) reads and executes the program code stored in the recording medium,
It goes without saying that it will be achieved. In this case, the program code itself read from the recording medium realizes the functions of the above-described embodiments, and the recording medium recording the program code constitutes the present invention.
Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also based on the instruction of the program code,
An operating system (OS) running on the computer does some or all of the actual processing,
It goes without saying that the processing includes the case where the functions of the above-described embodiments are realized.

Further, after the program code read from the recording medium is written in the memory provided in the function expansion card inserted into the computer or the function expansion unit connected to the computer, based on the instruction of the program code. , The CPU provided in the function expansion card or the function expansion unit performs some or all of the actual processing,
It goes without saying that the processing includes the case where the functions of the above-described embodiments are realized.

When the present invention is applied to the above recording medium, the recording medium stores the program code corresponding to the above-mentioned flowchart.

[0057]

As described above, according to the present invention, it is possible to obtain an effect that a moving image can be compressed with a lossless and high compression rate.

[Brief description of drawings]

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

FIG. 2 is a diagram for explaining a compression method performed by a PNG compressor 14.

FIG. 3 is a flowchart for explaining a procedure of compressing an image signal according to the same embodiment.

FIG. 4 is a diagram for explaining a method of reading image data according to the same embodiment.

FIG. 5 is a block diagram showing a configuration of a moving image compression apparatus according to a second embodiment.

FIG. 6 is a flowchart for explaining an operation procedure of the moving image compression apparatus according to the embodiment shown in FIG.

FIG. 7 is a diagram for explaining calling of pixels in the same embodiment.

FIG. 8 is a block diagram showing a configuration of a moving image compression apparatus according to a third embodiment of the present invention.

FIG. 9 is a view for explaining division of frames in the same embodiment.

10 is a flowchart for explaining an operation procedure of the moving picture compression apparatus shown in FIG.

FIG. 11 is a diagram for explaining an example of a data structure of image data in the third embodiment.

[Explanation of symbols]

11 memory 12, 83 Control unit 13, 51, 86 Data string creation unit 14 PNG compression unit 21 LZ77 compression 22 Huffman coding 23 Huffman decoding 24 LZ77 extension 81 Judgment unit 82 frame memory 84 Comparison section 85 memory 141 LZ77 Compressor 142 Huffman Coding Unit 821 S frame memory 822 D frame memory 851 Image data storage unit 852 Brightness change flag storage unit

Claims (10)

[Claims] 1. Storage means for storing a moving image composed of a plurality of frame images; luminance data of pixels in a predetermined column is extracted from each stored frame image in a horizontal scanning order; A data string creating means for creating a moving image data string by arranging brightness data strings and further arranging the brightness data strings created for all the columns of the frame image in the vertical scanning order, and using the PNG method. A moving image compression apparatus, comprising: a compression / encoding means for performing compression / encoding processing of a moving image data sequence. 2. Storage means for storing a moving image composed of a plurality of frame images, and brightness data of pixels at predetermined positions are extracted from each of the stored frame images, and the brightness data are arranged in frame order. A data string creating means for creating a moving image data string by creating a brightness data string and further arranging the brightness data strings created for all pixel positions of the frame image, and the moving image data using the PNG method. A moving image compression apparatus comprising: a compression / encoding means for performing a compression / encoding process of a column. 3. A determination unit that determines a reference frame image that serves as a reference for moving image compression from a plurality of frame images that form the moving image, and a first storage unit that stores the reference frame image. Second storage means for storing frame images other than the reference frame image, comparison means for calculating comparison information between the reference frame image and frame images other than the reference frame image, and storing calculated comparison information Third storage means, data creating means for creating a moving image data string based on the reference frame image and the calculated comparison information, and compression / encoding processing of the moving image data string using the PNG method. A moving picture compression apparatus comprising: a compression / encoding means for performing the operation. 4. The two kinds of brightness changes generated by the comparing means for the pixel at the same position in the reference frame image and the frame image other than the reference frame image, when the brightness value is the same and when the brightness value is different. The moving picture compression apparatus according to claim 3, wherein a flag is calculated as the comparison information. 5. The moving image data string is a data string in which luminance data of all pixels in the reference frame image are arranged in a scanning order, and luminance change flags of all pixels in a frame image other than the reference frame image in a scanning order. 5. The moving picture compression apparatus according to claim 4, wherein the arranged data string and the luminance data in the frame image when the luminance change flag shows the same luminance value as the reference frame image are arranged in frame order. . 6. A moving image compression method for compressing moving image data composed of a plurality of frame images stored in a storage device, wherein luminance data of pixels in a predetermined column is horizontally scanned from each stored frame image. A first step of sequentially extracting the luminance data, a second step of forming the luminance data sequence by arranging the luminance data in a frame order, and further arranging the luminance data sequences created for all the columns of the frame image in the vertical scanning order. A moving picture compression method, comprising: a third step of creating a moving picture data stream by means of; and a fourth step of performing compression / encoding processing of the moving picture data row using the PNG method. 7. A moving image compression method for compressing moving image data composed of a plurality of frame images stored in a storage device, wherein luminance data of a pixel at a predetermined position is extracted from each stored frame image. A first process, a second process of arranging the brightness data in a frame order to create a brightness data string, and a moving image by further arranging the brightness data strings created for all pixel positions of the frame image in a scanning order. A moving image compression method, comprising: a third step of creating a data string; and a fourth step of performing compression / encoding processing of the moving image data string using the PNG method. 8. A moving image compression method for compressing moving image data composed of a plurality of frame images stored in a storage device, wherein the moving image is compressed from a plurality of frame images forming the moving image. A first step of determining a reference frame image serving as a reference, a second step of calculating comparison information between the reference frame image and a frame image other than the reference frame image, and the reference frame image A moving image including a third step of creating a moving image data string based on the comparison information and a fourth step of compressing / encoding the moving image data string using the PNG method. Image compression method. 9. A first step of reading each stored frame image from a storage device storing a moving image composed of a plurality of frame images and extracting luminance data of pixels in a predetermined column in a horizontal scanning order, A second step of creating a brightness data string by arranging the brightness data in frame order, and a second step of creating a moving image data string by arranging the brightness data strings created for all the columns of the frame image in a vertical scanning order. A program for causing a computer to execute the step 3 and the fourth step of compressing / encoding the moving image data sequence using the PNG method. 10. A first computer which reads out each stored frame image from a storage device in which a moving image composed of a plurality of frame images is stored in a computer and extracts luminance data of pixels in a predetermined column in a horizontal scanning order. A procedure and a second procedure of creating the brightness data string by arranging the brightness data in frame order, and a moving image data string by further arranging the brightness data strings created for all the columns of the frame image in the vertical scanning order. A computer-readable recording medium in which a program for executing the third procedure for creating and the fourth procedure for performing compression / encoding processing of the moving image data sequence using the PNG method is recorded.