JPH0197067A - Picture data compressing and expanding system - Google Patents

Abstract

PURPOSE:To efficiently compress picture data including data of inefficient regulating ratio such as half tone by dividing picture data into a part where the repetition of a same pattern continues and a part except for said part, and compressing and expanding them i separate forms. CONSTITUTION:A picture coding processor 1 detects a repeating pattern where the repetition of the same pattern in picture data from a picture data memory 10 continues, compresses and encodes picture data in said part by the system based on the regularity of the pattern, and stores it in the area 12 of a work memory 5. The compression encoding is executed by the system including the repeating pattern and the number of repeating times. Picture data in the non- repeating pattern part is compressed and encoded by an MH system or an MR system and the like, and is stored in the area 11 if the memory 5. A repeating pattern decoding processor 2 decodes compressed and encoded data in the area 12, and a picture decoding processor 3 compressed and encoded data in the area 11. They synthesize and store data in a dot pattern memory 4 based on addresses corresponding to respective bits.

Description

[Detailed Description of the Invention] [Field of Application in Mining] The present invention relates to an information processing system that compresses and expands image data, and particularly relates to an information processing system that compresses and expands image data that includes repeating small patterns such as halftones. The present invention relates to an image data compression/expansion method suitable for use in.

[Conventional technology]

As a conventional technique related to the image data compression/expansion method, for example, M is a one-arrow run-length encoding method described in "CCITT Red Book (CCITT 几gDBOOK) Vol.
H (Modified-Huffman) method and MR (Modified-Huffman) method, which is a two-dimensional encoding method.
[Problems to be Solved by the Invention] In the prior art, when there are many parts in which small patterns such as 0'-7 tones are repeated in =yg data, There is a problem in that the compression efficiency of the image data in this part is low, and the data evidence after compression encoding increases.

An object of the present invention is to solve the problems of the prior art described above, to efficiently compress small patterns such as halftones, or portions of image data that are repeated, and to significantly reduce the amount of data after compression encoding. The object of the present invention is to provide a possible image data compression/expansion method.

[Means for solving problems]

According to the present invention, the object is to separate image data in a portion where small patterns are repeated from the original image data, and compress the image data in the separated portion using an algorithm using the regularity of the pattern. Then, embed space data in the part of the original image data where there was a repeating pattern,
This is achieved by compressing the warmed-up original data using a conventional method.

[For production]

For the original image and data, before compressing the mm data, the image data of the part where the same pattern is repeated several times in succession is extracted, and the extracted 9-stroke data part is Image data I (space data is embedded instead. Image data in which this space data is embedded is compressed by the MH method or Ma method according to the conventional technology. This compression compresses the original image data as it is. This can be done more efficiently than in other cases.Also,
The extracted image data of the repeated part of the same pattern is
It is compressed separately based on the regularity of repetition.

As a result, the original image data is compressed as efficiently as it is, and the amount of data after compression encoding is significantly reduced.

Also, in the decompression process, the compressed data of the repeated part is
The original image data is restored by combining the repeated portion with the extracted original 1jIIi hoe data based on the position information in the original image data added during compression processing.

, [Embodiment] Hereinafter, an embodiment of the artist data compression/expansion method according to the present invention will be described in detail with reference to the drawings.

Fig. 1 is a block diagram showing the overall configuration of an embodiment of the present invention, Fig. 2 is a flowchart explaining the process of extracting a repeating pattern from image data, and Fig. 3 shows the format of compressed data of the repeating pattern. FIG. 4 is a black diagram showing the configuration of a repetitive pattern decoding processor that decodes compressed data, and FIG. 5 is a configuration diagram of a memory that stores control information and compressed data. 1, 4, and 5, 1 is an image encoding processor, 2 is a repetitive pattern decoding processor, 3 is an image decoding processor, 4 is a dot pattern processor, 5 is a compressed data memory,
10 is an image data storage, 20 is a pattern register, 2
1 is a counter, 22 is an X address register, 23 is a Y address register, 24 is a pattern length register, and 25 is a control circuit.

As shown in FIG. 1, the image data compression/expansion method according to an embodiment of the present invention receives image data in the squadron data memory IO, extracts image data of a repetitive pattern portion (image data), When the image data of the repetitive pattern part is compressed, the image encoding processor 1 compresses the embedded image data such as space data in the extracted image data part, and the memory that stores the two types of compressed data and control f# information. Compressed data memory 5 having delimited areas 11 to 13
, a repetitive pattern decoding processor 2 that decodes each of the 21111 type compressed data, an image decoding processor 3, and a dot pattern memory 4 that stores the decoded image data.

An outline of the operation of the embodiment of the present invention constructed as described above will now be described.

When the image encoding processor 1 receives image data from the image data memory IO, it detects a repeating pattern in which the same batonine is repeated multiple times in succession in the image data, and extracts the image data of that part. , the image data of the repeated pattern portion is compressed and encoded using a method based on the regularity of the pattern. For example, as shown in FIG. 3, this compression encoding is performed based on the starting point address in the image data of the repeated pattern, the number of repetitions of the pattern, the length of the pattern, and the repeated pattern. This is done to create compressed data corresponding to a nine consecutive repeating pattern. In addition, in this case, one pattern that is repeated is, for example, a plurality of consecutive @0'' (or @1')
It is a series of data consisting of a plurality of consecutive @ll'' (t or ``0''), that is, a pattern of - pairs of white (black) dots and black (white) dots. As described above, the encoding processor 1 extracts the *e data of the repetitive pattern from the image data, strips space data into nine parts, and compresses and encodes the image data of this non-repetitive pattern by the MH method or the MFL method.

The compressed encoded data of the image data according to the non-repetitive pattern and the compressed encoded data of the image data according to the repeated pattern compressed and encoded as described above are stored in the menu areas 11 and 12 of the work memory 5, respectively.

The repetitive pattern decoding processor 2 decodes the compressed encoded data in the above-mentioned square area 12 and stores it in the dot pattern memory 4. The configuration and operation of this repetitive pattern decoding processor 2 will be described in detail later. On the other hand, the image decoding processor 3 decodes the compressed encoded data in the memory area 11. Since the compressed and encoded data in the memory area 11 is data compressed and encoded using the known M)1 method or MR method, the image decoding processor 3
Data compressed and encoded by the known MH method or MR method is decoded by a known method, expanded, and stored in the dot pattern memory 4. In the dot pattern memory 4, the decoded original image data from the repetitive pattern decoding processor 2 and the image virtualization processor 3 are stored.
They are synthesized and stored based on the addresses corresponding to the respective two-dimensional bits.

In the above description of FIG. 1, each of the nine devices shown as blocks constituting the embodiment of the present invention may be configured as a single device, or may be configured as a plurality of devices. It's so hot. Furthermore, a plurality of devices shown in each platform may be configured as an integrated device.

Next, the process of extracting a repeated turn portion from the original image data in the image data memory 10 in the image misformation processor 1 will be explained with reference to the flowchart shown in FIG.

(1) First, capture a pattern consisting of a set of one or more consecutive white dots and one or more consecutive black dots from the beginning of the original image data, and compare the data with that pattern. (Flow 3)
1.32).

(2) In this case, since it is the first pattern in the image data, comparison data is not yet available, so it is checked whether the pattern length of the imported pattern is less than or equal to a predetermined value (Flows 32 and 33). ).

(3) If the pattern length of the captured pattern is longer than a predetermined value, the MH method is better than extracting it as a repeated pattern and compressing it. Alternatively, compression processing using the MR method has higher compression efficiency, so this pattern is similar to the MH method described above.
The ninth output is processed using the MR method or the MR method (Flows 33 and 36).

(4) If the pattern length of the captured pattern is longer than the predetermined value, set the captured input cover pattern as a soft pattern and repeat the counter in order to check whether the pattern blocks light for multiple lines. is set to @1” (Flows 33 to 35).

(5) When the above-mentioned 70-35.36 is completed, it is checked whether processing for 12 inches of image data has been completed, and if processing for 1 line has not been completed, 70-35.36 is completed.
The process returns to step 31 (flow 43).

(6) Import the next pattern of white dots and black dots,
When the presence or absence of comparison data is checked, if there is no comparison data, the same processing as in the case of first data acquisition is performed.

(7) In flow 32, if there is a repeat pattern candidate as comparison data, check whether the next imported pattern matches the comparison pattern, and if they match, add 1 to the repeat counter and The entered data is discarded and the process proceeds to 70-43 described above (flow 32.37.42).

(817r: If the pattern imported in 1-37 does not match the comparison pattern, it is checked whether the value of the repetition counter is greater than or equal to a predetermined value.The repetition pattern candidate is evaluated. If enough data is obtained to separate and extract it as a repeating pattern, that is, if the value of the repeat counter is greater than or equal to a predetermined value, this repeating pattern is extracted and separated, and the separated repeating pattern is replaced with system space data. are output and stored in predetermined work areas on the mesh in the image encoding processor (Flows 37 to 40).

(9) If the value of the repetition counter 38 has not reached the predetermined value at 71:1-38, the repetition pattern is output as is to the work area on the memory. This is because if the amount of data of a repeating pattern is small, there is no advantage of compression processing as a repeating pattern (Flow 38.
41).

(lO) When the above-mentioned processes 7a-40 and 41 are completed, the next captured pattern that is inconsistent in flow 37 is selected as a repeat pattern candidate. processing is performed in the same way as for the first acquisition pattern.

(1) In the above processing, the light is blocked until the data processing for 1-7 minutes is completed, and when the data processing for 1 line is completed, the remaining comparison pattern is evaluated and post-processed to be output to the work area of the memory. is executed (flows 43 and 44)
).

The image encoding processor 1 extracts the repeating pattern by the following processing described above, and converts the image data of the repeating pattern into the format shown in FIG. X number of compressed encoded data and image data with non-repetitive patterns are stored in seven work areas. The image encoding processor 1 then generates mk data "4I" according to the non-repetitive pattern.
: Compression encoding is performed using the MH method or MR method.

In the format of the compressed data of the repeating pattern shown in Fig. 3, the start point address indicates the start address in the stroke data of the repeating pattern after the compressed data is expanded, and the number of repetitions indicates the number of repetitions of the repeating pattern that follows. Indicates how many times the pattern repeats, and the pattern length is 1 of the repeated pattern.
The dot length of each pattern is shown, and the rehearsed pattern is shown as it is, one pattern that is shielded from light. ``In this way, image data with a repetitive pattern can be efficiently compressed using the ratio compression method based on the regularity of the repetitive pattern. This compressed data also includes the data necessary for compositing with the non-repeating pattern, in this case the starting position of the repeating pattern within the image data. The image data is compressed by the MH method, MR method, etc., with the repeated portions of a small number of dots replaced with spaces. Compared to the original image data, this data has significantly fewer points of change between white dots and black dots, thereby improving compression efficiency.

Since the compressed multiplication data is stored in a separate area on the work memory, information for combining the two pieces of data is required. Therefore, as shown in FIG. 5, the address pointer P1. P2 is provided. The pointer Pi indicates the starting address of the memory area 11 in which compression encoded data of image data according to a non-repetitive pattern is stored,
The tL pointer P2 indicates the starting address of the memory area 12 where compressed image data based on a repetitive pattern is stored.

Next, the configuration and operation of the repetitive pattern decoding processor 2 will be explained (see diagram w14).

As shown in FIG. 4, the repetitive pattern decoding processor 2 has a pattern register 20 that stores the repetitive pattern.
The main components are a counter 21 in which the number of repetitions is set, an X address register 22 and a Y address register 23 in which the starting point address of the repetition pattern is set, a register 24 that stores the pattern length, and a control circuit 25. configured.

The correction data of the image data according to the repetitive pattern configured in the format shown in FIG.
is set to The repetitive pattern stored in the pattern register 20 is first written into the dot pattern memory 4 under the control of the control circuit 25 based on the addresses set in the X address register 22 and Y address register 23. When one writing of the repetitive pattern is completed, the value in the pattern length register 24C) is added to the value in the X address register 22 via the adder ADD,
The new nine X-direction addresses are stored in the X address register 22, and the value of the counter 21 is decremented by 1 via the subtracter. The repeating pattern in the pattern register 20 is again written to the dot pattern memory 4 based on the address in the X address register 22 with the new address. The repeated pattern decoding processor 2 repeats the above-described operation and reads the repeated pattern into the dot pattern memory 4 until the value of the counter 21 becomes zero. This process is controlled by the control circuit 25 based on the value of the counter 21.

In the above-mentioned example of the present invention, decoded and expanded image data is synthesized on the dot pattern memory 4, but starting point address data added to compressed data of image data based on a repetitive pattern is also used. Based on this, it is also possible to synchronize with the decoded non-repetitive data, take the logical OR of the output, and directly output it to a printer or the like.

〔Effect of the invention〕

As explained above, according to the present invention, by adding relatively simple logic in the process of encoding and decoding drawing method data, image data including halftone data and other data with poor compression efficiency can be efficiently processed. The image data can be compressed, the amount of image data can be reduced, and by reducing the amount of tfc and data, the data transfer time can be shortened, ts and lfm.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the overall configuration of an embodiment of the present invention, Fig. 2 is a flowchart explaining the process of extracting a 1 mA repeating pattern from the amount of image data, and Fig. 3 is the format of compressed data of the repeating pattern. FIG. 4 is a block diagram showing the configuration of a repetitive pattern decoding processor, and FIG. 5 is a configuration diagram of an image memory. 1------@image encoding processor, 2...
Repeated pattern decoding processor, 3... Image decoding processor, 4... Dot pattern memory, 5... Compressed data memory, 10...
Image data memory, 20...Pattern menus,
21...Counter, 22-...X address register, 23...Y address register, 2
4...Pattern length register, 25-...
control circuit. Figure 1 Figure 2 Figure 3 - Figure 4

Claims (1)

[Claims] 1. In an information processing system that compresses and expands image data, the image data is divided into a portion where the same pattern continues to be repeated and other portions, and each portion is compressed and encoded in a different format. An image data compression/expansion method characterized in that, when compressed data is expanded and decoded, data obtained by decompressing and decoding each compressed data in a format corresponding to each compression encoding is synthesized. 2. The image data compression/expansion according to claim 1, wherein the portion where the same pattern continues to be repeated is compressed and encoded in a format that includes at least the repeated pattern and the number of repetitions thereof. method.