JPS62120180A - Blocking entropy encoding system - Google Patents

Abstract

PURPOSE:To enable an effective data compression by encoding the second block including a non-peculiar event (for instance, a multivalued signal except for zero) discriminated to be a binary into a run length. CONSTITUTION:Signals of zero or that except zero of a prediction error of the picture signal of the output of a DPCM circuit 1 are inputted to a valid and invalid block discriminating circuit 2 and separated into blocks and the invalid block of the block of only zero and the valid block including the signal except for zero is discriminated. When it is discriminated that it is the valid block, the run length of the succeeding blocks is detected by a valid block run length encoder 6. Then, this run length is encoded into the run length code by a valid block run length encoder 7. Accordingly, the valid data compression is carried out.

Description

[Detailed Description of the Invention] [Summary] In a blocked entropy coding method for band compression of an image signal, the second By run-length encoding blocks, more effective data compression is possible.

[Industrial application field]

The present invention is suitable for blocking when the average run length of a signal of a characteristic event (for example, O) or a non-characteristic event (for example, a multivalued signal other than 0) is long, such as a prediction error output in band compression of an image signal. This paper relates to improvements in entropy coding (blocked variable length coding).

It is desired that the blocked entropy coding method described above be capable of more effective data compression.

[Prior Art and Problems to be Solved by the Invention] The conventional blocking En1-Lobby coding system will be explained using FIG. 4, taking as an example the case of outputting a prediction error of an image signal.

The prediction error output of the image signal which is the output of the DPCM circuit 1 is O or a signal other than O is sent to the valid/invalid block discriminating circuit 2.
is divided into blocks, and it is determined whether the block is an invalid block containing only 0 or a valid block containing signals other than O, and valid/invalid block discrimination information is input to the multiplexing circuit 4 and selector 5. do.

The prediction error output is input to a Huffman encoder (an encoder that provides an optimal code length according to the frequency of occurrence) 3, and all signals are Huffman encoded and input to a multiplexing circuit 4, which generates valid/invalid block discrimination information. After the Huffman code of the effective block is multiplexed with a 1-bit 1 code in block units,
input to selector 5.

Selector 5 selects O for each block when it is an invalid block.
is selected and a 1-bit 0 code is output, and when it is a valid block, a 1-bit code and a Huffman encoded code for all signals are selected and output.

However, although valid blocks are often consecutive, each block is assigned a code of 1 and output, so there is a problem that sufficient data compression cannot be achieved.

[Means for solving problems]

The above problem is that the binary information that has been determined into binary information, whether it is the first block consisting only of unique events or the second block containing non-specific events, is run-length encoded for the second block. This is solved by the inventive blocked entropy coding scheme with means (6°7).

[Effect]

According to the present invention, the determined binary information is run-length encoded for the second block containing a non-specific event (for example, a multilevel signal other than 0) (6.7>, so each block is run-length encoded. Since no code is given to the two blocks and a run-length code is given to the second continuous block, the code length becomes shorter and more effective data compression becomes possible.

(Example) FIG. 1 is a block diagram of a first embodiment of the present invention.

In the figure, 6 indicates an effective block run length detector, and 7 indicates an effective block run length encoder, and the same reference numerals indicate the same functions throughout the figures.

The difference between FIG. 1 and FIG. 4 is that an effective block run length detector 6 and an effective block run length encoder 7 are provided.

As a result, the valid block run length detector 6 detects the continuous run length of the valid block determined as 1 by the valid/invalid block discriminating circuit 2, and the valid block run length is detected with respect to this run length. length encoder 7
This is run-length encoding.

Therefore, consecutive effective blocks are collectively run-length coded instead of being assigned a code of 1 for each block, which enables more effective data compression.

FIG. 2 is a block diagram of a second embodiment of the present invention.

In the figure, 8 is a zero/non-zero discrimination circuit, 9 is a zero run length detector, and 0 is a zero run length detector.
denotes a run length encoder, and II denotes a selector.

To explain the difference between FIG. 2 and FIG. 1, the zero/non-zero discrimination circuit 8 discriminates whether the prediction error output, which is the output of the DPCM circuit 1, is zero or non-zero. If it is zero, Lebel's No. 41 is output and input to the selector 11 and zero run length detector 9.
Based on the valid/invalid block discrimination information from the invalid block discrimination circuit 2, a zero run length in the valid block is detected, run length encoded by a zero run length encoder 10, and input to the selector 11.

The selector 11 outputs a 1 based on the zero/non-zero discrimination information. If it is zero, it outputs a run-length code, and if it is non-zero, it outputs a Huffman code. The multiplexing circuit 4 outputs a 1 based on the valid/invalid block discrimination information. , the data for each valid block output from the selector 11 is collected while the valid blocks are continuous, and the run length code from the valid block run 1/length encoder 7 is multiplexed 1, inputted to the selector 5, and the valid blocks are In the invalid block discrimination information, an O code is output for each invalid block, and a run-length code is output for consecutive valid blocks. A Huffman code is output.

In this case, consecutive valid blocks are not coded with 1 for each pro-ac, but are run-length encoded all at once, and consecutive zeros of the valid blocks are also run-length encoded. Therefore, the code length becomes even shorter than in the case of FIG.

FIG. 3 is a block diagram of a third embodiment of the present invention.

In the figure, 12 is a non-zero run length detector, 13 is a non-zero run length encoder, and 14 is a multiplexing circuit.

To explain the difference between FIG. 3 and FIG. 2, the zero/non-zero discrimination circuit 8 determines the Lebel signal as non-zero and outputs it, and the non-zero run length detector 12 discriminates between valid and invalid blocks. circuit 2
The non-zero run length in the valid block is detected by valid/invalid block discrimination/reporting, and the run length is encoded by the non-zero run length encoder 13 and input to the multiplexing circuit 14. , the zero/non-zero discrimination information from the zero/non-zero discriminator circuit 8 is used to multiplex the non-zero with the Huffman encoded one in the Huffman encoder 3, and input it to the selector 11. Depending on the discrimination information, if it is zero, the run length code output from the zero run length encoder 10 is output, and if it is non-zero, the multiplexed run length code and Huffman code output from the multiplexing circuit 14 are output. Then, in the multiplexing circuit 4, run-length codes are multiplexed with respect to consecutive valid blocks, as in the case of FIG. , a run-length code is output for consecutive valid blocks, a run-length code for a zero in the valid block, and a run-length code and a Huffman code for a non-zero.

In this case as well, consecutive valid blocks are not assigned a code of 1 for each block, but are run-length encoded all at once, and consecutive zeros in the valid blocks are run-length encoded. The code length is further shortened compared to the case shown in FIG.

〔Effect of the invention〕

As explained above in detail (according to the present invention, since consecutive effective blocks are run-length encoded, the code length becomes short, and data compression can be performed more effectively).

[Brief explanation of drawings]

FIG. 1 is a block diagram of a first embodiment of the present invention, FIG. 2 is a block diagram of a second embodiment of the present invention, FIG. 3 is a block diagram of a third embodiment of the present invention, and FIG. The figure is a block diagram of a conventional example. In the figure, ■ is a DPCM circuit, 2 is a valid/invalid block discrimination circuit, 3 is a Huffman encoder, 4.14 is a multiplexing circuit, 5.11 is a selector, 6 is a valid block run length detector, 7 is a valid block 8 is a zero/non-zero discrimination circuit; 9 is a zero run length detector; 10 is a zero run length encoder; 12 is a non-zero run length detector; 13 is a non-zero run length encoder.

Claims (3)

[Claims] (1) Means for discriminating a block obtained by dividing a signal sequence into a set unit into two values: a first block consisting only of unique events, or a second block containing non-specific events (2)
), the Huffman encoding circuit (3) performs Huffman encoding on the signal in the second block;
It is characterized in that it comprises means (6, 7) for run-length encoding the value information for the second block, and the second block is Huffman encoded and a run length of the Huffman code is added. Blocked entropy coding method. (2) Means for determining whether a block obtained by dividing a signal string into a set unit is a first block consisting only of unique events or a second block containing non-specific events (2)
), a Huffman encoding circuit (3) that performs Huffman encoding on non-unique events in the second block, and run-length encoding means (9, 10) that performs run-length encoding on unique events; Means for run-length encoding the determined binary information for the second block (
6, 7), wherein each event in the second block is encoded, and a run length of the second block is further added. (3) Means for determining whether a block obtained by dividing a signal sequence into a set unit is a first block consisting only of unique events or a second block containing non-specific events (2
), a Huffman encoding circuit (3) that performs Huffman encoding on non-unique events in the second block, run-length encoding means (9, 10) that performs run-length encoding on unique events, and a non-unique run-length encoding means (12, 13) for run-length encoding the event, and means (6, 7) for run-length encoding the determined binary information for the second block; The non-unique events of the second block are Huffman encoded and the run length of the Huffman code is added, the unique events are run length encoded, and the run length of the second block is added. A blocked entropy coding method characterized by the following.