CN101202809B

CN101202809B - Compression method for row buffer

Info

Publication number: CN101202809B
Application number: CN2007101794855A
Authority: CN
Inventors: 霍晓方
Original assignee: Vimicro Corp
Current assignee: Vimicro Corp
Priority date: 2007-12-13
Filing date: 2007-12-13
Publication date: 2011-02-16
Anticipated expiration: 2027-12-13
Also published as: CN101202809A

Abstract

The invention discloses a compressing method used for a line buffer so as to effectively utilize the leisure space of a line memorizer and save recourse. The method includes of the following steps: dividing the line buffer into a plurality of areas which form an array after being arranged in a horizontal mode and a vertical mode respectively; writing the image data line by line until the last line; sequentially outputting the image data fully arranged on the areas of a same line until each area on the same line is completely empty; transferring the image data on a corresponding area to each empty area by taking a plurality of areas on one diagonal of the array as a shaft.

Description

A kind of compression method that is used for line buffer

Technical field

The present invention relates to a kind of method of image transmission, more specifically, relate to a kind of method that is used for JPEG (the Joint Photographic Experts Group) compression of line buffer.

Background technology

A kind of at the photograph image and the standard of widely used a kind of distortion compression during JPEG.Because JPEG is based on the compression algorithm of 8X8 macro block, this 8X8 macro block specifically as shown in Figure 1.Usually, the size of line buffer is the 64X2X8=1024 byte, and this line buffer is divided into 8 row, every behavior 128 bytes, and 8 bytes are a sub-piece in every row, being divided into is 16 sub-pieces.We are divided into 8 districts to 16 sub-pieces, and each district is totally 2 sub-pieces.The Yi Hanghe district is a base unit, and line buffer has just formed the macroblock array of 8 row and 8 row like this, and whole line buffer can be divided into 64 zones, and each divides into the sub-piece of 2 1X8 sizes,, is respectively the first sub-piece and the second sub-piece that is.Be the position that is easy to illustrate that each is regional, can quote a pair of coordinate in each zone and represent.

In the method for prior art, imageing sensor is an image of exporting each row according to the mode of row successively, promptly, export the same view data that lists of each row simultaneously, so must temporarily be stored among the RAM data of each row, in RAM, store the image of continuous 8 row, just begun to carry out the JPEG compression.In image compression, imageing sensor also continues output image, so need other RAM to be used to store follow-up view data.General method is the line buffer r memory image with two 8 row, with the mode alternation of table tennis.

Therefore, the JPEG compression method that is used for line buffer of prior art has taken more resource, is unfavorable for reducing cost.

Summary of the invention

The technical problem that solves of the present invention is to propose a kind of compression method that is used for line buffer, by reasonably utilizing the clear area in the line buffer, make line buffer in output image data, can store new view data effectively again, and need not additionally to utilize again a line buffer.

According to a kind of compression method that is used for line buffer of the present invention, this method comprises a line buffer is divided into a plurality of zones that these a plurality of zones are arranged the back with horizontal and vertical form respectively and formed array; Write view data line by line, until last column; When view data was written to this last column regional by row, output write that full same what list should the zone all be sky respectively until being positioned at this being positioned at view data on the zone of same row successively; To be axle with a plurality of zones that are on one of them diagonal of this array, will respectively should be the zone of sky with vacating that view data on the regional corresponding zone moves; Wherein, when the view data on writing the zone that completely is being positioned at same row was moved, output was write to expire and is comprised also that in the view data that is arranged on the zone of same row output is in the allochthonous view data in the zone of these same row.This each zone is divided into the first and second sub-pieces further.So, when the sub-piece on the same row same position of each row is write full view data, export the view data in the sub-piece that is stored on this same position.

Particularly, method of the present invention also comprises view data is written to step in the first sub-piece of a predetermined column of last column; The view data of exporting in the first sub-piece of this predetermined column all is empty step until the first sub-piece of this predetermined column; With will move step in the first sub-piece of this predetermined column with the view data in the first sub-piece of each row in this corresponding row with the first sub-piece of this predetermined column.

Further, method of the present invention comprises that also continuation is written to view data the step in the second sub-piece of this predetermined column; The view data of exporting in the second sub-piece of this predetermined column all is empty step until the second sub-piece of this predetermined column; With will move step in the second sub-piece of this predetermined column with the view data in each the second sub-piece in this corresponding row with the second sub-piece of this predetermined column.

The method according to this invention comprises that also it is empty zone that new view data is continued to write line by line after moving.

Description of drawings

Below in conjunction with accompanying drawing,, make technique scheme of the present invention and other a bit apparent by description to preferred embodiment of the present invention.

Fig. 1 has shown the block plan of the line buffer of prior art;

Fig. 2 A-Fig. 2 Z shown utilize compression method of the present invention to view data output and write schematic flow sheet;

Fig. 3 has shown the storage organization schematic diagram after SECTOR-SEVEN is output;

Fig. 4 has shown the storage organization schematic diagram after last district of line buffer is read, and wherein first to the 7th row has write new view data.

Embodiment

Hereinafter, will describe the present invention in detail.

The method that the present invention specifically utilizes the line buffers of 8 row to carry out JPEG compression, and be 64 with the width of image, picture format is that YUV422 is that example is described this method.

As shown in Figure 1, the zone that method of the present invention needs at first will be on one of them diagonal of macroblock array is defined as axis, and for example: this is in the diagonal zone should be zone (0,0), zone (1,1) ... zone (7,7).Then, read successively in the JPEG module after each macro block of this axis one side, the view data of axis opposite side is moved in the respective regions of this side.

Particularly, shown in Fig. 2 A is block plan at a line buffer of the present invention, for technical scheme of the present invention is described better, one set of image data of coming tabular form writing with label M, the position of representing these view data places with coordinate method, wherein row-coordinate 0-7 represents first to the 8th row respectively, and ordinate 0-7 represents first to the 8th row (or zone), represents the first sub-piece and the second sub-piece under each row respectively with label a and b.Like this, the view data that is stored in the trizonal first sub-piece of fourth line just can be represented by M32a.

At first, when first row had been stored in the line buffer to the 7th all data of going, the imageing sensor (not shown) began to have write the data of last column.When its M70a has been written in the line buffer, this moment first macro block (the first sub-piece of first area 0 a), i.e. M00a, M10a, M20a ... M70a all set, JPEG module (not shown) is read this first macro block.

After dateout, the storage of this line buffer is shown in Fig. 2 B, and the memory location of this first macro block all is empty.Certainly, at this moment, view data still is written to this last column constantly.

Then, shown in Fig. 2 C, first row, second to the Section Eight the data of each first sub-piece a, be M01a, M02a ... M70a, move on to the corresponding position in this first macro block respectively, this moment, the segment space of row 0 was empty, and the data of imageing sensor can continue to be written in the row 7.

Next, JPEG module (not shown) is read second macro block (being first area 0 second sub-piece b), and the memory location of this second macro block is empty like this, shown in Fig. 2 D.

The data of each second sub-piece b among first row, 0, the second to the eight district 1-7, i.e. M01b, M02b ... M07b moves on to corresponding position in second macro block respectively, this moment first row 0 space sky fully, and that imageing sensor is also write last column 7 is full, as Fig. 2 E.

JPEG continues to read the 3rd macro block, and (second area 1 first sub-piece a).On the one hand, one group of new data can be begun to be written to first row 0, for example: data N00a, N00b...; On the other hand, because the data M 01a in first row 0 has moved on in first district 0, when reading the data of the 3rd macro block, need and to export in the lump by allochthonous data M 01a, shown in Fig. 2 F.

Similarly, second row 1, the data of each first sub-piece a in the 3rd to Section Eight 1-7, be M12a, M13a ... M17a, move on to corresponding position in the 4th macro block respectively, this moment, the segment space of second row 1 was empty, and the new data of imageing sensor can continue to be written in first row 0, shown in Fig. 2 G.

JPEG continues to read the 4th macro block (second area 1 second sub-piece b).Because the data M 01b in first row 0 has moved on in first district 0, when reading the data of the 3rd macro block, need and to export in the lump by allochthonous data M 01b, shown in Fig. 2 H.

Similarly, second row 1, the data of each second sub-piece b in the 3rd to Section Eight 1-7, be M12b, M13b ... M17b, move on to corresponding position in the 3rd macro block respectively, this moment, whole spaces of second row 1 were empty, and the new data of imageing sensor can continue to be written in first row 0, shown in Fig. 2 I.

The rest may be inferred, and with reference to Fig. 2 J～Fig. 2 Z, the JPEG module can continue to read remaining macro block, by moving corresponding graphic data, can be implemented in vacant line and write new data.Storage organization after the JPEG module runs through SECTOR-SEVEN 6, as shown in Figure 3.

At last, after the JPEG module read the total data of Section Eight 7, its storage organization as shown in Figure 4.At this moment, the new data of other seven row have stored in the line storage fully, and line storage of the present invention like this can begin next circulation again.

Certainly; the present invention also can have other various embodiments; under the situation that does not deviate from spirit of the present invention and essence thereof; being familiar with those of ordinary skill in the art ought can make various corresponding changes and distortion according to the present invention, but these corresponding changes and distortion all should belong to the protection range of the appended claim of the present invention.

Claims

1. a compression method that is used for line buffer is characterized in that, this method comprises

One line buffer is divided into a plurality of zones, and these a plurality of zones are arranged the back with horizontal and vertical form respectively and are formed array;

Write view data line by line, until last column;

When view data was written to this last column regional by row, output write that full same what list should the zone all be sky respectively until being positioned at this being positioned at view data on the zone of same row successively;

To be axle with a plurality of zones that are on one of them diagonal of this array, will respectively should be the zone of sky with vacating that view data on the regional corresponding zone moves;

Wherein, when the view data on writing the zone that completely is being positioned at same row was moved, output was write to expire and is comprised also that in the view data that is arranged on the zone of same row output is in the allochthonous view data in the zone of these same row.

2. compression method according to claim 1 is characterized in that this method comprises

This each zone further is divided into the first and second sub-pieces.

3. compression method according to claim 2 is characterized in that, when the sub-piece on the same row same position of each row is write full view data, exports the view data in the sub-piece that is stored on this same position.

4. compression method according to claim 3 is characterized in that this method also comprises

View data is written in the first sub-piece of a predetermined column of last column;

The view data of exporting in the first sub-piece of this predetermined column all is empty until the first sub-piece of this predetermined column;

To move in the first sub-piece of this predetermined column with the view data in the first sub-piece of each row in this corresponding row with the first sub-piece of this predetermined column.

5. compression method according to claim 4 is characterized in that this method also comprises

Continuation is written to view data in the second sub-piece of this predetermined column;

The view data of exporting in the second sub-piece of this predetermined column all is empty until the second sub-piece of this predetermined column;

To move in the second sub-piece of this predetermined column with the view data in each the second sub-piece in this corresponding row with the second sub-piece of this predetermined column.

6. compression method according to claim 1 is characterized in that, this method comprises that also it is empty zone that new view data is continued to write line by line after moving.

7. compression method according to claim 1 is characterized in that, the size of this line buffer is 1024 bytes.

8. compression method according to claim 7 is characterized in that, this line buffer is divided into 64 zones.

9. compression method according to claim 7 is characterized in that, this line buffer is divided into 8 row and 8 row.