JPS6132665A - Compression decoding method for binary picture information - Google Patents

Abstract

PURPOSE:To make it possible not to waste time in decoding and to perform efficient decoding by decoding picture information in the line for the current decoding at once without referring picture information in the previous line when the picture information in the previous line is given in white in a facsimile equipment. CONSTITUTION:When the encoded binary picture information of a memory 3A is read out at the time of decoding, a flip-flop 4 is connected with a read-out data line D3 of a picture information memory 3A to store it if said information is white picture information. In case that the flip-flop 4 is set by black image information at the time of decoding binary picture of the line L1, a decoding part 2 reads at once binary picture information of line L2 for the present decoding from a memory 3B without doing re-read-out of binary picture information of the line L2 without referring binary picture information of line L1. At this time, if the binary picture information of line L2 is white one, the white picture information is outputted at once.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a binary image information compression and decoding system used in facsimile machines and the like.

[Prior art]

Generally, a facsimile signal (binary image information) extracted from a document or the like has extremely high redundancy. For this reason, facsimile machines and the like have been used conventionally.

A compression/decoding device is used that reduces the redundancy of a facsimile signal, compresses the transmission band, transmits it, and decompresses it on the receiving side.

The band compression methods used here are Modified Huffman encoding (MH), which is a one-dimensional encoding method, and Modified FREAD (MR), which is a two-dimensional encoding method, as determined by the International Telegraph and Telephone Advisory Committee. A typical example is the encoding method.

Both of these MH and MR encoding methods detect changed pixels based on binary image information extracted from the original image, and calculate the distance from the origin to the changed pixel (run length) or the distance from the changed pixel to the next changed pixel. The distance is detected, and based on this distance information, binary image information is encoded according to a predetermined encoding rule, and its band is compressed.

However, when decoding encoded binary image information using the MR method, the encoded binary image information is stored in the image information memo IJ [temporarily stored, then reread for decoding, and the current line's binary The image information is decoded by referring to the binary image information of the previous line. Therefore, even if the image information is all white across multiple lines, the image information memory must be reread, resulting in wasted decoding time and poor decoding efficiency. there were.

[Purpose of the invention]

The present invention has been devised in view of the drawbacks of the conventional methods described above, and its purpose is to provide a binary image information compression/decoding method that can perform decoding more efficiently.

[Structure of the invention]

The present invention provides a memory means for storing that the image information of the line is white image information when decoding the encoded binary image information of each line, and the encoded binary image information of the primary line is provided. At the time of decoding, if the memory means remembers that the previous line is white image information, the encoded binary image information of the line is stored without referring to the encoded binary image information of the previous line. It is designed to be decrypted.

〔Example〕

Hereinafter, the present invention will be described in detail based on illustrated embodiments.

FIG. 1 is a block diagram showing an embodiment of the present invention, in which coded binary image information G is inputted line by line to a data buffer 1 via a transmission device (not shown), and is further input to a decoding unit. 2, the image information is temporarily stored in the image information memories 3A and 3B.

Here, take a note of the image information! J3A and 3B have a memory capacity that can store encoded binary image information for one line, and as shown in the data format of Fig. 2, each line is inputted with a line end signal EOL added. Regarding the binary image information G, the image information G of the previous line L is temporarily stored in the memo 1J3AK, and the image information G of the next line L is temporarily stored in the memo IJ3B.

In this case, image information memo! Encoding 2 for J3A, 3B
Value image information is sent to the decoding unit 2 via data lines D, ,D.
Writing and reading thereof are performed by read/write control signals KW, , KW,. The encoded binary image information at the time of readout operation is stored on the data line D,
, D4 to the decoding unit 2.

On the other hand, in the read data line D3 of the image information memory 3A, there is a flip-flop that stores, if the coded binary image information of this memo IJ3A is white image information when read out during decoding. P4 is connected.

In this configuration, if the image information memo 93B
The operation for decoding the binary image information stored in the image data will be explained based on the flowchart shown in FIG.

When decoding the binary image information of the line L2 stored in the memory 3B, the decoding unit 2 first decodes the flip-flop 4.
Determine whether or not is set (step 10)
. As a result, if the flip 70 knob 4 is not set, that is, if the line L1 contains black image information, the line L stored in the image information memory 3A is
1 (step 11), and reads out the binary image information of the current line Lt to be decoded (step 12), referring to the binary image information of the previous line L, The binary image information of the line L to be decoded is decoded (step 13). However, if the flip-flop 4 is set by black image information when decoding the binary image information on line L1, the decoding unit 2 does not read out the binary image information on line L again and immediately reads the current image information. Line L to be decoded! is decoded without binary values (step 15). At this time,
Line L! If the binary image information is white information, white image information is immediately output.

In this way, the previous line 2 of the current line to be decoded
If the value image information is white image information.

The binary image information of the current line to be decoded is immediately decoded without referring to the binary image information of the previous line. Therefore, it is possible to efficiently decode a facsimile signal or the like containing a large amount of white image information, and it is expected that the transmission time can be shortened.

〔Effect of the invention〕

As explained above, according to the present invention, when the image information of the previous line is white, the image information of the current line to be decoded is immediately decoded without referring to the image information of the previous line. Therefore, there is no waste in the decoding time, and decoding can be performed efficiently. As a result, effects such as the ability to transmit facsimile image signals and the like at even higher speeds can be expected.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing the data format of encoded binary image information, and FIG.
The figure is a flowchart showing the decoding operation of the embodiment. l...Data buffer, 2...Decoding unit, 3A. 3B... Image information memory, 4... Flip-flop. Figure 1 Figure 2

Claims (1)

[Claims] It has an image information memory that stores encoded binary image information for a predetermined number of lines encoded according to a predetermined encoding rule, reads encoded binary image information for each line from this image information memory, and In a binary image information compression/decoding method that restores the original image information of the current line by referring to the encoded binary image information of the previous line, when decoding the encoded binary image information of each line, the decoding 2 of the line is A memory means is provided for storing that the value image information is white image information, and when decoding the encoded binary image information of the next line, the memory means stores information that the previous line is white image information. A binary image information compression/decoding method characterized in that under stored conditions, encoded binary image information of the current line is decoded without referring to encoded binary image information of the previous line.