JP2812064B2 - Image processing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention is applied to an image processing apparatus having a data storage memory. In particular, the present invention relates to adaptive compression encoding means for binary data stored in a data storage memory.

[0002]

2. Description of the Related Art As shown in FIG.
Is subjected to MH encoding, MR encoding, or MMR encoding in the encoding unit 15, and the encoded and encoded data 21 is stored in the data storage memory 19. Encoding unit 15
When encoding is performed in the encoding table memory 16
Is required. Then, the encoded data 22 stored in the data storage memory 19 is input to the decoding unit 17,
Here, MH decoding, MR decoding, or MMR decoding is performed to produce black and white binary data 23. When decoding is performed by the decoding unit 17, a decoding table memory 18 is required.

[0003]

In such a conventional example, black-and-white binary data is converted to MH code, MR code or MM code.
Since data compression is performed using the R code, the encoding unit requires an encoding table memory, and the decoding unit also requires a decoding table memory, which increases costs. Further, when the MH code, the MR code or the MMR code is performed, the information is expanded more than twice depending on the pattern of the black and white binary data. For example, encoding binary data alternated between black and white with the MH code has a disadvantage that the information amount is expanded to 4.5 times.

An object of the present invention is to eliminate such disadvantages and to provide an image processing apparatus having a compression encoding means capable of performing high-speed encoding.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a compression encoding means for compressing and encoding black and white binary data, and a data storage memory for storing black and white binary data compressed and encoded by the compression encoding means. In the image processing apparatus, the compression encoding means includes a run length counter for counting the run length of the black and white binary data, and a black and white of a run length shorter than a predetermined run length in accordance with a command from the run length counter. A raw data encoding unit that encodes the binary data; and a run length exceeding the predetermined run length among the run lengths counted by the run length counter unit, using a variable length run length code. Variable-length run-length coding unit for performing the conversion, and black-and-white run information for adding black-and-white run information indicating the result of the determination as to whether the run included in the output of the variable-length run-length coding unit is white or black. Additional part A code selecting unit for selecting one of the output of the raw data encoding unit and the output of the black and white run information adding unit according to the run length counted by the run length counter unit. And

Here, a run length shorter than the predetermined run length is assumed.
Is for the block 1 part of Weyl coding.
Weil as variable length code for lock 2 and above
The encoding is performed.

[0007]

The expansion ratio of the coding is reduced for the binarized black-and-white data pattern, and the occurrence probability distribution of the black-and-white data run is fixed for the variable-length run-length coding. This makes it unnecessary to use an encoding and decoding table memory.

[0008]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the overall configuration of this embodiment. FIG. 2 is a detailed block diagram of the adaptive binary data compression encoding unit shown in FIG. This example is
As shown in FIG. 1, this embodiment comprises, as shown in FIGS. 1 and 2, a compression encoding means for compressing and encoding black-and-white binary data, and a black-and-white binary compressed and encoded by the compression encoding means. A data storage memory 3 for accumulating encoded data, and an adaptive binary data compression encoding unit 1 serving as a compression encoding means includes a run length counter unit 8 for counting the run length of the monochrome binary data.
A raw data encoding unit 9 for encoding black-and-white binary data having a run length shorter than a predetermined run length in accordance with a command from the run length counter unit 8; and a run counted by the run length counter unit 8. The variable-length run-length encoding unit 10 performs encoding using a Weil code for a run length exceeding the predetermined run length among the lengths, and the run included in the output of the variable-length run-length encoding unit 10 is white. Black / white run information adding unit 11 for determining whether the color is black or black and adding black / white run information indicating the result of the determination
And the output of the raw data encoding unit 9 or the monochrome run information adding unit 11 according to the run length counted by the run length counter unit 8.
Code selecting section 12 for selecting one of the outputs
And

Next, the operation of this embodiment will be described. The monochrome binary data 4 is encoded by the adaptive binary data compression encoding unit 1, and the output encoded data 5 is stored in the data storage memory 3. The stored encoded data 6 is decoded by the adaptive binary data compression / decoding unit 2 and output as black and white binary data 7. The black-and-white binary data 13 is input to the run length counter 8 and the raw data encoder 9. The run length counter unit 8 counts the white and black run lengths of the input data, and outputs the run number information to the raw data encoding unit 9, variable length run length encoding unit 10, and code selector 12. . The raw data encoding unit 9 performs raw data encoding on data having a small number of runs. The variable-length run-length encoding unit 10 performs variable-length run-length encoding on a code whose run number is not small. The code data output from the variable-length run-length encoding unit 10 is input to a black-and-white run information adding unit 11 for adding information of a white run or a black run, where it is determined whether it is a white run or a black run. In the black and white run information adding unit 11,
It also requires the encoded data result of raw data encoding. The coded data output from the raw data coding unit 9 and the coded data output from the variable length run length coding unit 10 and output with white or black run information added by the black and white run information adding unit 11 are Either code is selected according to the information on the number of runs input to the code selector 12 and output from the run length counter unit 8, and is output as encoded data 14.

[0010]

[Table 1] Table 1 shows an example of the adaptive binary data compression encoding of the present invention. Block 1 in Table 1 belongs to run lengths “0” to “3”, and the run length of the inputted binary black and white data is “3”.
In the following cases, “0” is added to the head address, and 3 bits of raw data are added after the leading address, resulting in a 4-bit equal length code. At the time of raw data encoding, there is no need for information on whether a white run or a black run. When the run length of the black and white binary data is “4” or more, the configuration is like block 2 to block n.
In this embodiment, a Wyle code in which a run length occurrence probability distribution is proportional to a negative power distribution is used as a variable-length run-length code when the run length of black and white binary data is “4” or more. Is added with one bit of information for distinguishing between a white run and a black run. As a result, the worst elongation of the code is suppressed to 1.33 times or less, and the coding table memory is deleted by assuming the run length occurrence probability distribution to be a negative power distribution.

[0011]

As described above, the present invention switches between raw data encoding and variable-length run-length encoding in accordance with the run length of black-and-white data when compression-coding black-and-white binary data. Therefore, it is possible to reduce the code expansion rate for an arbitrary pattern of the black and white data, and it is possible to achieve high-speed encoding and high-speed decoding.

Further, since the occurrence probability distribution of black and white data runs is assumed and fixed for variable-length run-length encoding, the encoding and decoding table memory can be omitted.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the overall configuration of an embodiment of the present invention.

FIG. 2 is a block diagram showing a partial configuration of the embodiment of the present invention.

FIG. 3 is a block diagram showing the configuration of a conventional example.

[Explanation of symbols]

 1 Adaptive Binary Data Compression Encoding Unit 2 Adaptive Binary Data Compression Decoding Unit 3, 19 Data Storage Memory 4, 7, 13, 20, 23 Black and White Binary Data 5, 6, 14, 21, 22 Code Coded data 8 run length counter 9 raw data encoder 10 variable length run length encoder 11 black and white run information adding unit 12 code selector 15 encoding unit 16 encoding table memory 17 decoding unit 18 decoding table memory

Claims (1)

(57) [Claims] 1. An image processing apparatus comprising: compression encoding means for compressing and encoding black and white binary data; and a data storage memory for storing monochrome binary data compressed and encoded by the compression encoding means. The compression encoding means includes a run length counter for counting the run length of the black and white binary data, and a Weyl encoding block in response to a command from the run length counter.
Of run length binarized data of 3 or less corresponding to lock 1
A raw data encoding unit for performing raw data encoding, and four or more of the run lengths counted by the run length counter unit
Block to the run length greater than the run length of Weil coding
A variable-length run-length encoding unit that performs Weyl encoding using two or more codes, and determines whether a run included in the output of the variable-length run-length encoding unit is white or black. A black-and-white run information adding unit for adding run information, and either the output of the raw data encoding unit or the output of the black-and-white run information adding unit is selected according to the run length counted by the run length counter unit. An image processing apparatus, comprising: