KR100365118B1 - Apparatus and method for dithering and compressing data of dynamic picture image - Google Patents

Abstract

The present invention provides a dithering / compression apparatus for moving picture data that allows dithering and compressing moving picture data of multiple levels to a level that can be displayed on a terminal in order to display the moving picture data having multiple levels to a terminal supporting only a lower level of display. And a method comprising: a first delay module (20) for delaying an input block; A parameter extraction module (30) for outputting a control signal (E2) according to a degree of difference between the delayed previous block (A2) and the currently input block (A1); A dithering module 40 for dithering the block A1 and selectively outputting one of the dithered current block and a block D2 of a restored previous frame according to the control signal E2; After performing the bitwise exclusive OR operation between the output block B2 and the block D2 of the dither module 40 and compressing the calculated block and the output block B2 of the dithering means, respectively, A compression module 50 for selectively outputting one of each compressed frame data; Restoration module 60 for restoring the output (C2) of the compression module; And a second delay module 70 delaying the restored block F2 and providing the block D2 to the dithering module 40 and the compression module 50, thereby remarkably improving image quality and compression efficiency. Improve.

Description

Apparatus and method for dithering and compressing data of dynamic picture image}

The present invention relates to an apparatus and method for dithering / compressing video data, and more particularly, to transmit video data having multiple levels to a terminal supporting only a smaller level of display to display the video data having multiple levels. An apparatus and method for dithering / compressing video data for dithering and compressing to a displayable level in a.

In general, when transmitting a video to a wireless Internet terminal, the channel capacity of the communication network is low speed and most terminals can display only black and white, so that the black and white video is transmitted to reduce the amount of video data, Dithered and compressed image data is transmitted to make a boundary line look natural.

FIG. 1 is a schematic block diagram of a general system for dithering and compressing video data. Each frame of a video is dithered through an existing dither module 11 for still images, and the dithered frame is converted into a compression module 12. FIG. Compress and send separately.

In the conventional general video data dithering and compression system as shown in FIG. 1, each frame of the video is independently dithered and compressed by the dithering module 11 and the compression module 12. Each frame before and after can be dithered differently in the background area that is not actually moving, which is not only annoying to the human eye, but also adversely affects the compression performance. Compression ratio cannot be expected, and in order to transmit the dithered result in pixel units and transmit them to various terminals having different levels of display capability, the dithered and compressed information must be transmitted several times according to the level of each terminal. There was this.

The present invention was created to solve the above problems, and its purpose is to extract the difference information between the current frame and the previous frame and use it in the dithering process, thereby dithering the video data to improve the image quality and to increase the compression ratio. And to provide a method.

Another object of the present invention is to compress a difference between a dithered image frame and a reconstructed previous dithered frame, or to compress and compress video data by selectively applying a lossless compression method and a lossy compression method. It is to provide.

It is still another object of the present invention to dither and compress a multilevel image by first generating a relatively low level dither image and then using this information to generate a relatively high level dither image, thereby generating a single bit stream. The present invention aims to provide a scalable dithering / compressing device for moving image data that can include dithered and compressed information for various levels to improve transmission and storage efficiency.

1 is a schematic block diagram of a general system for dithering and compressing video data,

2 is a block diagram of an apparatus for dithering / compressing video data according to an exemplary embodiment of the present invention.

3 is a detailed block diagram of the parameter extraction module of FIG.

4 is a detailed block diagram of the dithering module of FIG. 2;

5 is a detailed block diagram of the compression module of FIG.

6 is a detailed block diagram of the restoration module of FIG.

7 is a flowchart of a compression method according to the present invention applied to the compression module of FIG.

8 is a block diagram of a scalable dithering / compression apparatus of video data according to another embodiment of the present invention.

FIG. 9A illustrates an example of an output block B2 of the dithering module of FIG. 2, FIG. 9B illustrates an example of an output block D2 of the delay module of FIG. 2, and FIG. 2C illustrates an compression module of FIG. 2. An example of the output block E5 of the logic operation unit of FIG. 2 is an example of a block in which the lossy compressor method is applied to the block E5 in the compression module of FIG. 2.

※ Explanation of code for main part of drawing

20,70: delay module 30: parameter extraction module

31: difference calculation unit between blocks 32: comparison unit

40, 81, 84: dither module 41: dither unit for still images

42,54: Selective output 50,82,85: Compression module

51,53: compression unit 52,65: logical operation unit

60,83: restoration module 61,66: path selector

62,63: restoration unit 64: delay unit

86: transmission unit

In order to achieve the above object, a device for dithering / compressing video data according to the present invention is a device for dithering and compressing a video into a unit block, which is a partial frame divided into frames or arbitrary numbers, and dithering an input frame. Dithering means for selectively outputting one of a block of a current dithered frame and a block of a reconstructed previous frame; Control means for extracting difference information between a block of a current frame and a block of a previous frame and controlling selection of the dithering means according to the extracted information; After performing an exclusive-OR operation on a bit-by-bit basis between the output of the dithering means and the block of the restored previous frame, compressing the computed block and the output of the dithering means, respectively, and then compressing each of the compressed blocks Compression means for discriminating the data from each other and selectively outputting one of the data; And restoration restoring means for restoring the output of the compression means according to the division indication and providing feedback to the dithering means and the compression means to the restored previous frame.

In the present invention configured as described above, the dithering means includes a dithering unit for still image dithering a block of a currently input frame; And an output selection for selectively outputting one of a block of the current dithered frame, which is an output of the still image dithering unit, and a block of the restored previous frame restored and fed back by the recovery feedback means according to a control signal of the control means. And a control unit comprising: a delay unit for delaying a block of an input frame for a predetermined time; A difference calculator which calculates a mutual difference value between the block of the delayed previous frame and the block of the currently input frame; And a comparing unit for comparing the obtained difference value with a predetermined threshold value and outputting a binary control signal for controlling the selection of the dithering means according to the comparison result, wherein the dithering means and the control means As a result, the image quality of the motionless background area is significantly improved.

In addition, the compression means includes a first compression unit for compressing the output of the dithering means; A logic operation unit performing an exclusive-OR operation in units of bits between the output of the dithering means and the block of the restored previous frame; A second compression unit compressing an output of the logical operation unit; And a comparison selection unit for comparing the outputs of the first compression unit and the second compression unit with each other and selectively outputting the smaller ones as a result of the comparison, wherein the first and second compression units are lossless or lossy compression. The method is optionally applied, and the compression means thus configured significantly improves the compression ratio than the conventional one.

In order to achieve the above object, a scalable dithering / compression device for moving picture data according to the present invention is an apparatus for dithering and compressing a moving picture into a unit block, which is a frame or a partial frame divided into a random number, the frame being currently input. First dithering means for dithering a block of N into a lower level image of a predetermined number of bits; First compression means for compressing the dithered block; Restoring means for restoring the output of the first compression means; Dividing a block of a frame currently input based on the output of the restoring means into a higher level image having a greater number of bits than the predetermined number of bits, and then forming the pixel of each pixel of the block dithered into the higher level image. Second dithering means for outputting only the remaining bits by setting the bit value determined by the output of the first compression means as an upper value; Second compressing means for compressing an output of said second dithering means based on an output of said restoring means; And storing the output data of the first compression means and the output data of the second compression means as information on a single image, and storing the divided data according to the display level of the corresponding receiving terminal upon request of the terminal. The present invention is configured to include a transmission means for transmitting data in combination with each other or in combination with each other, and according to the present invention configured to include dithered and compressed information for various levels in one transport bit stream, the transmission and storage efficiency are improved.

In order to achieve the above object, a dithering method of moving picture data according to the present invention is a method of dithering and compressing a moving picture into a unit block which is a partial frame divided into frames or arbitrary numbers. First step; Extracting mutual difference information between the block of the delayed previous frame and the corresponding block of the currently input frame; And a third step of dithering and outputting the block of the currently input frame or outputting the block of the dithered previous frame based on the extracted information. This is improved than before.

In order to achieve the above object, a method of compressing video data according to the present invention is a method of compressing divided video data by dividing each frame (or a block divided by a unit) into a block of a currently dithered frame. A first step of compressing; A second step of performing an exclusive-OR operation in units of bits between the block of the current dithered frame and the corresponding block of the previously dithered frame that has been previously compressed and reconstructed; Compressing a block computed through the second step; And a fourth step of dividing the block compressed through the first step and the block compressed through the third step and selectively outputting one of the divided blocks, in particular, the first and the second In the compression in the third step, if the number of frames for compression, the block divided by the frame, and the number of '0' or '1' of the bits in the sub-block divided by the block is less than the predetermined number, a lossy compression method is performed. In the above case, by performing a lossless compression method, the compression rate is remarkably improved.

Next, a dithering / compression apparatus and method for moving picture data according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the moving picture, each frame is processed as one unit or each frame is divided into block units. Since it is processed, it will be described as an example that the processing is divided into blocks for the convenience of the following description.

FIG. 2 is a block diagram of an apparatus for dithering / compressing video data according to an exemplary embodiment of the present invention. As shown in FIG. 1, a first delay module 20 delaying an input block for one frame time; A parameter as a selection control means for extracting a mutual difference between the previous block A2 delayed through the first delay module 20 and a block A1 currently input and outputting a control signal E2 according to the extracted difference degree. Extraction module 30; A dither module (40) for dithering the currently input block (A1) and selectively outputting one of the dithered current block and a block (D2) of the restored previous frame according to the control signal (E2); A bit-wise exclusive-OR operation is performed between the block B2 output through the dithering module 40 and the block D2 of the restored previous frame, and the operation of the calculated block and the dithering means is performed. A compression module 50 for compressing the output block B2 and selectively outputting one of the respective compressed frame data; A restoration module 60 for restoring the output C2 of the compression module; And delaying the block F2 restored through the restoration module 60 for one frame time and providing the dithering module 40 and the compression module 50 to the block D2 of the restored previous frame. It consists of two delay modules (70).

3 is a detailed block diagram of the parameter extraction module 30 of FIG. 2. As shown in the figure, the previous block delayed and outputted through the current block A1 and the first delay module 20 is shown. Calculate the mutual difference between (A2) using the Summed Absolute Difference (SAD) method, or the Summed Squared Difference (SSD) method. A difference calculation unit 31 between two blocks; And a comparison unit for comparing the difference value calculated by the difference calculation unit 31 with a preset threshold and outputting the control signal E2 for controlling the selection of the dither module 40 according to the comparison result. 32).

FIG. 4 is a detailed block diagram of the dither module 40 of FIG. 2, and as shown in the figure, a still image dithering unit 41 for dithering the currently input block A1; And a dithered current block D1 and the second delay module which are outputs of the still image dithering unit 41 according to the control signal E2 output from the comparing unit 32 of the parameter extraction module 30. And a selection output section 42 for selectively outputting one of the blocks D2 of the restored previous frame, which is the output of 70.

FIG. 5 is a detailed block diagram of the compression module 50 of FIG. 2. As shown in the figure, the block B2 output through the output selection unit 42 of the dither module 40 is shown. A first compression unit 51 for compressing according to the quaternary tree structure compression method; A logic operation unit 52 for performing an exclusive-OR operation in units of bits between the block B2 and the block D2 of the restored previous frame; A second compression unit (53) for compressing the block (E5) output through the logical operation unit (52) according to a ternary tree structure compression method; And a selective output unit 54 which compares the output F5 of the first compression unit 51 and the output G5 of the second compression unit 53, and selects and outputs the smaller one of the comparison data. It consists of).

In addition, the first and second compression units 51 and 53 compress the corresponding block according to the ternary tree structure compression method, but the '0' or '' of the corresponding block for the compression and the bits in the lower block of the block are compressed. When the number of 1 'is less than the predetermined number is applied to the lossy compression method, if the above is characterized by applying a lossless compression method, such a compression method will be described in detail with reference to FIG.

FIG. 6 is a detailed block diagram of the restoration module 60 of FIG. 2. As shown in FIG. 2, a first path of the output of the selective output unit 54 of the compression module 50 is classified according to the division. Or a first path selector 61 which selects and transmits one of the second paths; A first restoring unit (62) for restoring the output of the selection output unit (54) transmitted through the first path by a quaternary tree restoring scheme; A second restoring unit (63) for restoring the output of the selection output unit (54) transmitted through the second path by a quadruple tree structure restoring method; A delay unit 64 for delaying the restored block F2, which is the final output of the restoration module 60, for one frame time; A logic operation unit 65 performing an exclusive-OR operation in units of bits between the output block of the second recovery unit 63 and the output block of the delay unit 64, that is, the block at the same position of the previous frame. ; And selecting one of an output of the first restoring unit 62 or an output of the logical operation unit 65 to perform a final operation to the restored block F2 in a corresponding operation with the first path switching unit 61. It consists of two path selector 66, on the other hand, the receiving terminal is provided with a restoring module having the same configuration as the restoring module 60 to recover the bitstream transmitted by dithering, compressed and transmitted from the apparatus of the present invention.

7 is a flowchart of a compression method according to the present invention applied to the first and second compression units 51 and 53 of the compression module 50 of FIG. 2. First, after setting a T value (S71). The corresponding block to be input, that is, the block B2 output through the output selection unit 42 or the block E5 output through the logical operation unit 52, is inputted to the input block B2 or E5. In step S72, it is determined whether the number of bits' 1 'is less than the set number T (S72). If the result of the determination of S72 is YES, all the' 1's are regarded as' 0 'and compressed. The lossy compressed data stream (F5 or G5) is output as '0' by compressing by the lossy compression method (S73). If the result of the determination in S72 is no (N), it is determined in the input block (B2 or E5). It is determined whether the number of bits' 0 'is less than the set number T (S74). If the result of the determination of S74 is yes, all of the' 0's are regarded as' 1 '. The lossy compressed data stream (F5 or G5) is outputted as '10' by compressing by the lossy compression method of compression (S75). If it is determined that it is no (N), the input block (B2 or E5) is determined. ) By adding '11' to the result of steps S73 and S75 and resetting the T value set in step S71 to be T / 4 (S76), and then inputting the current block (B2 or E5). Is divided into four sub-blocks, and each block divided is performed again from the step S72 (S77).

In addition, after performing step S73 or step S75, it is determined whether a subblock remains in the block currently being processed (S78), and if yes (Y), for each remaining block (S79) from step S72 again. If no (N) is to be terminated (that is, processing the next block entered).

In the above description, the delay time of each of the delay modules 20 and 70 and the delay unit 64 is set as a preferred processing time of one frame on a frame basis, but the present frame is obtained when the difference information between frames is obtained in the present invention. The delay time may be set to one or more frames to select and use one of frames before the previous frame, but in this case, each frame and / or block may be marked with a selection bit to identify each. To be recognized.

FIG. 8 is a block diagram of a scalable dithering / compression device for moving image data according to another embodiment of the present invention. As shown in FIG. 8, a first dithering dithering a block A1 currently input into a binary level image is shown in FIG. Module 81; A first compression module 82 for compressing the dither block B8 through the first dither module 81; A restoration module 83 for restoring the output C8 of the first compression module 82; Based on the output D8 of the restoration module 83, the currently input block A1 is dithered into a photo level image, and then corresponding bits among the pixels forming the pixels of the block dithered into the photo level image. A second dithering module 84 for outputting only the remaining bits other than the bits forming each pixel of the block restored through the restoration module 83; A second compression module (85) for compressing the output (E8) of the second dithering module (84) based on the output (D8) of the restoration module (84); And a transmitter for storing and / or mutually combining the output C8 of the first compression module 82 and the output F8 of the second compression module 85 according to the display level of the corresponding receiving terminal. 86).

Next, the operation of the present invention will be described.

First, the video is processed by each frame as one unit or each frame is processed by being divided into block units. Hereinafter, the operation is divided into blocks for convenience of description in the following description.

The block A1 of the nth frame currently input is the block delayed for one frame time in the delay module 20, that is, the block A2 at the same position as the block A1 in the n-1th previous frame. Together with the parameter extraction module 30 is input.

The difference calculating unit 31 of the parameter extraction module 30 calculates a difference value F3 between the two input blocks A1 and A2, and the difference value F3 corresponds to a difference for each pixel. It is calculated using the Summed Absolute Difference (SAD) method or the Summed Squared Difference (SSD) method of each pixel. The calculated difference value F3 is input to the comparison unit 32 and compared with a preset threshold value T3. As a result of the comparison, the difference value F3 is larger than the threshold value T3. 32 outputs '1' as a control signal E2 as a result, and outputs '0' when small.

The dither module 40 receives the current block A1 and the block D2 of the restored previous frame as inputs, and the dithering unit 41 for the still image of the dither module 40 receives the input current. The dither block A1, and the selection output unit 42 dithers the current block dithered by the still image dithering unit 41 based on the control signal E2 output from the comparing unit 32. D1) and one of the input block D2 of the restored previous frame are selected and output. That is, the selection output unit 42 selects and outputs the block D2 of the previous frame when the value of the control signal E2 is '0', and when the value is '1', the dithered current block. Select (D1) to output.

The compression module 50 inputs the block B2 selected and output through the selection output unit 42 of the dither module 40 and the block D2 of the restored previous frame as inputs. Perform. First, the input block B2 is compressed to a ternary tree structure through the first compression unit 51. Subsequently, the logical operation unit 52 performs an exclusive logical sum operation in units of bits between the block B2 and the block D2, and the second compression unit 53 is computed and output by the logical operation unit 52. A block E5 is input and compressed and outputted after the ternary tree structure. For example, the block D2 of the restored previous frame is smaller than the block B2 which is the current output of the dithering module 40. As a result of passing through the dither module 40 before the frame, for example, when the block B2 is the same as in FIG. 9A, the block D2 is typically the block (D) as shown in FIG. 9B. Compared with B2), there are very few bit differences (here only one bit difference in the point source). Accordingly, as a result of performing an exclusive OR operation between the block B2 and the block D2, the block E5 is the blocks in FIGS. 9A and 9B as shown in the bits in the point sources of FIG. 9C. Compared with each other, only the different bit parts are represented by '1' and the rest are all represented by '0'. Thus, the amount of data of the ternary tree structure compression resulted through the second compression unit 53 becomes very small.

That is, when the block B2 of FIG. 9 (a) is compressed as it is, the compression resultant data stream is '111011110111101111011', whereas FIG. 9 (c) is the output of the logical operation unit 52. In the case of compressing the block (E5) of the hexadecimal tree structure, the data stream appears as '100010001' as a result of the compression, thereby improving the compression efficiency.

Furthermore, according to the new compression method of the present invention, the first and second compression units 51 and 53 may use a '0' or '' of a frame for compression or a block divided therein or a bit in a sub-block of the block. If the number of 1 'is a predetermined number (T), for example, less than two, the lossy compression method is applied, and if it is abnormal, a lossless compression method is applied. According to this compression method, the output of the logical operation unit 52 Bit '1' in the point source of block E5 in Fig. 9 (c) is regarded as '0' and becomes like the block in Fig. 9 (d), and the block in Fig. 9 (d) is compressed to a ternary tree structure. In this case, the compression resulted in the data stream appearing as '0', which further improves the compression efficiency compared with the lossless compression method.

Summarizing the compression method of the present invention, a lossless coding compression is performed by dividing and compressing a subblock of a next step unless all bits in a block are '0' or '1' by a conventional conventional quadrature tree compression module. Although only the first and second compression units 51 and 53 of the present invention are applied, in order to increase the compression ratio, when the number of '0' or '1' in the block is small, the subblock of the next step is skipped. Compression of the current block can be completed without going to it. Compression rate and image quality can be adjusted by adjusting the parameter value as the preset number T. If the parameter T is '0', the lossless ternary tree structure Same as compression.

As such, the first data stream F5 as an output result of the first compression unit 51 and the second data stream G5 as an output result of the second compression unit 53 are the selective output unit. (54) are inputted to be compared with each other, and as a result of comparison, the smaller ones of the data amount are selected and output, but when the data amount of the first data stream F5 is smaller, the selection bit is '0'. Is added to the leading end of the first data stream F5, and if the amount of data of the second data stream G5 is smaller, the selection bit is set to '1' and the leading end of the second data stream G5. In addition, by selectively outputting, it is possible to distinguish whether the kind of the selectively outputted data stream is any of the first and second data streams F5 and G5. In this way, the data stream C2 output through the selection output unit 54 of the compression module 50 is transmitted to the receiving terminal and simultaneously input to the restoration module 60.

The data stream C2, which is the output of the compression module 50, is restored and output from the restoration module 60, and the output F2 of the restoration module 60 is driven by the second delay module 70. After a delay of one frame time, a feedback is provided to the dithering module 40 and the compression module 50 to the block D2 of the restored previous frame and used as described above.

The restoration module 60 receives the output C2 of the compression module 50 as an input and performs the following operation. The first bit of the leading end of the output data stream C2 of the restoration module 50 is a selection bit added by the selection output unit 54. The first path selection unit 61 of the restoration module 60 If the selection bit is '0', the rest of the subsequent bit stream is input to the first restoring unit 62 to restore the resultant block, and if the selection bit is '1', the rest of the subsequent bit stream is output. The bit stream is input to the second restoring unit 63 to be restored, and the logical operation unit 65 is configured to be restored by the output block of the second restoring unit 63 and the delay unit 64. The final output F2 of 60) inputs a reconstruction block delayed for one frame, that is, a reconstruction block at the same position of the previous frame, and then performs an exclusive-OR operation in units of bits. Subsequently, when the selection bit is '0', the second path selector 66 selects and outputs the output of the first restoring unit 62 as the final output F2 of the restoring module 60, and 1 ', the output of the logical operation unit 65 is selected as the final output F2 of the restoration module 60 and output.

Next, the operation of the scalable dithering / compression apparatus for moving picture data according to the present invention will be described with reference to FIG. 8.

The current input block A1 is dithered into a binary image through the first dither module 81, the output B8 of the first dither module 81 is compressed through the first compression module 82, As a result of the compression, the bit stream C8 is generated and stored or transmitted through the transmission unit 86 according to the application. The bitstream C8 is reconstructed through the reconstruction module 83, and the reconstructed binary image block D8 is input to the second dithering module 84 together with the current input block A1. The second dither module 84 dithers each pixel value of the block A1 into a photo level image according to each pixel value '0' or '1' of the block D8. The photographic image level output through the second dither module 84 has one of four values ('00', '01', '10', and '11') for each pixel. It is common to display two bits such as 01 ',' 10 ', or' 11 ', but one of the bits is already determined by the corresponding pixel value of the block D8, and the information of the block D8 is Since the bitstream C8 is already stored or transmitted by the transmitting unit 86, the second dither module 84 is already stored or transmitted by the transmitting unit 86 as the bitstream C8. Outputs a block E8 representing only the remaining information other than 1 bit (that is, 1 bit per pixel), and the output block E8 is compressed by the second compression module 85, and the compression result The bit stream F8 is generated and stored or transmitted through the transmitter 86 according to the application thereof. The output C8 of the first compression module 82 and the output F8 of the second compression module 85 are stored and / or mutually transmitted according to the application level, for example, according to the display level of the corresponding receiving terminal. .

For example, when the output C8 of the first compression module 82 is '1', the block A1 input to the second dither module 84 may be described. Even if the corresponding pixel value of is '01', the second dithering module 84 sets the corresponding pixel value '01' to '10' close to the output 'C8' bit '1', and then to '10'. Among the two bits, only the remaining bit '0' except for '1', which is a bit already determined by the output C8 of the first compression module 82, is compressed and transmitted or stored. On the other hand, when the output C8 bit of the first compression module 82 is '0', even if the corresponding pixel value of the block A1 input to the second dither module 84 is '10', The second dithering module 84 sets the corresponding pixel value '10' to '01' close to the bit '0' of the output C8, and the first compression module ( Only bit '1' other than '0' which is a bit determined by the output C8 of 82) is compressed to be transmitted or stored.

That is, for a specific terminal capable of displaying a binary level, only the bitstream C8 outputted through the first compression module 82 is transmitted through the transmitter 86 to be received by the corresponding terminal and restored. And / or for the terminal capable of displaying the photo level, the bit stream for the binary level image and the bit stream for the photo level image are not generated and transmitted, respectively, as in the prior art. The bit stream C8 of the binary level output through the first compression module 82 and the bit stream F8 of the binary level data size output through the second compression module 85 are serially coupled to each other. A terminal capable of transmitting the bitstream (C8 + F8) for the combined multiple (in this case binary and photo) level to be received and restored by the terminal (i.e. display binary level) Terminal capable of restoring only the C8 and display the picture level is being restored when the C8 + F8). As a result, the bit stream F8 output through the second compression module 85 has a size of the bitstream data for the binary level image and is combined with the bit stream C8 for the binary level image. By being a bitstream for an image, the amount of storage and transmission data is significantly reduced by subtracting the data size for a binary level from the data size for a photo level image, thereby greatly improving storage efficiency and transmission efficiency.

As described in detail above, the apparatus and method for dithering / compressing moving image data according to the present invention use existing information in which each frame is independently dithered and losslessly compressed by using information between frames for dithering and compressing and introducing a lossy compression technique. Compared to the method, the image quality and the granularity of the dithered image can be improved, and scalable dithering and compression can be performed, thereby significantly reducing the storage cost and the transmission cost when the display level of the terminal is varied as in the current mobile communication environment. . Therefore, according to the present invention, the image quality of a motionless background region, etc. in the video is improved than before, and the compression rate is remarkably improved than before, and the information dithered and compressed to fit various levels in one transport bit stream is included. The effect is to increase the transmission and storage efficiency.

Claims (18)

An apparatus for dithering and compressing a video into unit blocks that are frames or partial frames divided into any number, Dithering means for dithering an input unit block, and selectively outputting one of a unit block of a currently dithered frame and a unit block of a previous frame to be restored; Control means for extracting difference information between a unit block of a current frame and a unit block of a previous frame and controlling selection of the dithering means according to the extracted information; After performing an exclusive-OR operation in units of bits between the output of the dithering means and the unit block of the restored previous frame, compressing the calculated unit block and the output of the dithering means, respectively, Compression means for selectively displaying the divided unit block data and outputting one of them; And Dithering / compressing apparatus for restoring the output of the compression means and including a recovery feedback means for feeding back to the dithering means and the compression means as a unit block of the restored previous frame. The method of claim 1, The control means includes a delay unit for delaying the input unit block for a predetermined time; A difference calculator for obtaining a mutual difference value between the unit blocks of the delayed previous frame and the unit blocks of the currently input frame; And And a comparator for comparing the obtained difference value with a preset threshold and outputting a binary control signal for controlling the selection of the dithering means according to the comparison result. The method of claim 2, The difference calculator dithers the video data using the sum of absolute values of the differences per pixel (SAD) or the summed squared difference (SSD) method for each pixel. / Compressor. The method of claim 1, The dithering means may include: a dithering unit for still image dithering a unit block of a currently input frame; And An output selection for selectively outputting one of a unit block of the current dithered frame, which is the output of the still image dithering unit, and the restored previous frame unit block provided by the restoration feedback means and supplied according to a control signal of the control means Dithering / compression device for moving picture data comprising a portion. The method of claim 1, The compression means includes a first compression unit for compressing the output of the dithering means; A logic operation unit performing an exclusive-OR operation in units of bits between the output of the dithering means and the unit block of the restored previous frame; A second compression unit compressing an output of the logical operation unit; And And a comparison selection unit for comparing the outputs of the first compression unit and the second compression unit with each other and selectively outputting the smaller ones as a result of the comparison. The method of claim 5, And the first and second compression units use a quadruple tree structure compression method, and selectively apply a lossless or lossy compression method. The method of claim 6, The first and second compression units apply a lossy compression method when the number of '0' or '1' of the frame for compression or the divided block and the number of bits in the subblock of the block is less than a predetermined number. The dithering / compressing device of the video data, characterized by applying a lossless compression method. The method of claim 1, The restoration feedback means includes restoration means for restoring the output of the compression means; And And a delay unit configured to delay the unit block restored by the restoration unit for a predetermined time period and provide the dithering unit and the compression unit to the unit block of the restored previous frame. Device. The method of claim 8, The restoring means includes: a restoring unit restoring an output of the compression means; A delay unit for delaying the output of the restoration means for a preset time; A logic operation unit configured to perform an exclusive-OR operation in units of bits between the output of the recovery unit and the output unit block of the delay unit; And And an output selection unit for selectively outputting one of the output of the restoration unit and the output of the logical operation unit to correspond to the output selection of the compression unit. The method of claim 2, 8 or 9, The preset time is a set time of one frame or more in units of frames, and when the set time exceeds the time of one frame, dithering / compression apparatus for moving picture data, characterized in that the respective bits are displayed as division bits so as to distinguish each other. An apparatus for dithering and compressing a video into unit blocks that are frames or partial frames divided into any number, First dithering means for dithering a unit block of a currently input image by a predetermined number of bits; First compression means for compressing the dithered unit block; Restoring means for restoring the output of the first compression means; Dithering a unit block of an image currently input based on the output of the restoring means to a greater number of bits than the predetermined number of bits; Second dithering means for outputting only the remaining bit values with the bit value determined by the output of the first compression means among the bits forming each pixel of the dithered unit block as an upper value; Second compressing means for compressing an output of said second dithering means based on an output of said restoring means; And Output of the first compression means and output of the second compression means And transmitting means for distinguishing data from each other and storing the information as one image and transmitting the divided data singly or in combination with each other according to the display level of the corresponding receiving terminal upon request of the terminal. Scalable dithering / compressor for moving video data. The method of claim 11, And the predetermined number of bits is one, and the number of bits greater than the predetermined number of bits is two. In a method of dithering a video into unit blocks that are frames or partial frames divided into any number, Delaying an input unit block; Extracting mutual difference information between the unit blocks of the delayed previous frame and the unit blocks of the currently input frame; And And dithering and outputting the unit block of the currently input frame or outputting the unit block of the dithered previous frame based on the extracted information. An apparatus for compressing dithered video data into unit blocks that are frames or partial frames divided into any number, Compressing a currently dithered unit block; A second step of performing an exclusive-OR operation in units of bits between the current dithered unit block and a unit block of a previously dithered frame that is previously compressed and reconstructed; A third step of compressing the unit block calculated through the second step; And And a fourth step of dividing the unit blocks compressed through the first step from the unit blocks compressed through the third step and selectively outputting one of the divided unit blocks. Compression method. The method of claim 14, Compression in the first and the third step is a compression method of moving picture data, characterized in that using the quaternary tree structure compression method. The method according to claim 14 or 15, In the compression in the first and third stages, lossy compression when the number of frames for compression, the block divided by the frame, and the number of '0' or '1' of the bits in the sub-block divided by the block is less than the predetermined number And a lossless compression method if abnormal. The method of claim 14, In the fourth step, each of the compressed frames is allocated with one different selection bit to discriminate from each other, and the smaller amount of data among the divided frames is selected and output. . In the restoring apparatus of a terminal for receiving a dithered and compressed video signal to restore the unit block data which is a frame or a partial frame divided into any number, Restoring means for restoring the received and input video signal into unit block data; Logic operation means for performing an exclusive-OR operation in units of bits between the output of the recovery means and the previously restored unit block data; Output selection means for selecting one of the output of the recovery means and the output of the logical operation means according to the selection bit displayed at the time of transmission; And And delay means for delaying the output of the output selection means for one frame or more time and providing feedback to the logical operation means with the previously restored unit block data.