JPS61186074A - Coding processing system - Google Patents

Abstract

PURPOSE:To improve the efficiency of coding by adding a coded data at each unit block to the head of a coded data of a prescribed level plane and omitting the coded data not including an effective data. CONSTITUTION:A picture signal DI representing a density at each picture element in multi-value is outputted from a scanner 1 to a picture image processing section 2 in parallel. The picture image processing section 2 outputs a reference line signal LR and a coded line signal LC from a picture signal with a minimum level to the coding processing section 3 synchronously with a shift clock SC when a line synchronizing signal SY is outputted from the coding processing section 3. Further, a level signal DP corresponding to the level is outputted. The coding processing section 3 does not output a level plane signal corresponding to the coded data and the level signal DP when no effective data is obtained. However, when the level signal DP represents a level plane outputted at first in the unit block, the level plane signal and the coded data are outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an encoding processing method that divides multi-level read image information into information of a plurality of level planes and encodes each of the level planes separately.

[Prior Art] When inputting a color image, an image processing device such as a facsimile machine separates the color image into multiple color components (usually three primary colors), reads each color component separately, and generates color plane information corresponding to each color component. is forming.

In addition, when inputting a halftone image, the image is read into a multi-valued image signal of multiple bits, a level plane consisting of data of the same digit of the bit is formed, and each level plane is processed and output as an image signal separately. ing.

By the way, image information has a much larger amount of information and is highly redundant, so in devices that transmit image information such as facsimile machines and devices that store image information such as image file devices, one image information If the image information is processed as it is, the efficiency will be extremely low, so encoding processing is performed to reduce the redundancy of the image information, and the encoded data is transmitted or stored.

For example, a G3 facsimile machine has two encoding modes: a one-dimensional encoding mode (MH encoding mode) and a two-dimensional encoding mode (MR encoding mode), and image information is encoded using either method. Compression improves transmission efficiency.

In each of these encoding processes, one scanning line of the original is one unit of encoding, and in one-dimensional encoding mode,
A run length encoding process is performed to detect a change in the state of a pixel and encode the run length.

In addition, the two-dimensional encoding mode is an encoding process that encodes one line one-dimensionally and then two-dimensionally encodes a maximum of 11 consecutive lines. This is a sequential encoding method in which the position of each changed pixel on the line being encoded is encoded by referring to the position of the corresponding reference pixel on the encoding line or the reference line immediately preceding the encoding line. After encoding a coded line, the coded line is used as a reference line for the next coded line. (C
(See CITT Recommendation T, 4) Examples of encoded data formats in one-dimensional encoding mode and encoding formats in two-dimensional encoding mode are shown in FIGS. 4 and 5, respectively.

The encoding format of the one-dimensional encoding mode is such that the encoded data DC of each line is separated by the line end signal EOL for identifying each line, and the encoding format of the two-dimensional encoding mode is the line end signal EOL for identifying each line. A tag bit TAG indicating the encoding processing mode of the encoded data DC is added between the encoded data DC and the encoded data DC.

Now, considering the method of encoding color plane information formed by reading a color image and level plane information formed by reading a halftone image as described above,
For each scanning line, each level plane is encoded in the above-mentioned one-dimensional encoding mode or two-dimensional encoding mode, and these are consecutively encoded in the order of the scanning line, and each level plane is added to the beginning of each encoded data. What is necessary is to add identification information to identify the .

According to this method, for example, in one-dimensional encoding mode,
The format will be as shown in FIG.

That is, a level plane signal LL-L4 is added between the line end signal HOL and the encoded data DC, corresponding to the level plane of each encoded data DC, and these four encoded data DC are combined into a unit block (this (in the case of 1 scanning line).

However, in such a method, encoded data DC of all level planes is output, so for example, when a level plane corresponds to color information, even encoded data of color information that does not actually exist is outputted. In the figure, the level L2 of the (n+1) line. (n+2) line level L2. L3
．． Since the signal is output as shown as L4, the coding rate is low.

[Objective] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an encoding processing method that improves encoding efficiency without outputting unnecessary encoded data.

[Configuration] In order to achieve this objective, the present invention outputs encoded data for each unit block with encoded data of a predetermined level plane at the beginning, and omits encoded data that does not include valid data. I try to do that.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an image information processing apparatus according to an embodiment of the present invention.

In the figure, a scanner 1 reads a multi-value halftone image recorded on a read document, and outputs the read multi-value information to an image processing section 2 in parallel as a multi-bit image signal DI. That is, an image signal DI in which the density of each pixel is multi-valued is sent from the scanner 1 to the image processing unit 2.
output in parallel.

The image processing unit 2 temporarily stores the parallel input image signal DI in a line buffer (not shown) for each bit. When the line synchronization signal SY is output from the encoding processing unit 3, the reference line signal L is selected from a predetermined level (for example, level 1, which is the minimum level) of the one-picture signal DI.
R and the encoded line signal LC are output to the encoder 3 in synchronization with the shift clock SC applied from the encoder 3. Further, immediately before outputting the reference line signal LR and the encoded line signal LC, a level signal DP corresponding to the level thereof is outputted to the encoding processing section 3.

The encoding processing unit 3 temporarily stores the level signal [)P inputted first after raising the line synchronization signal SY,
Thereafter, the data of the encoded line signal LC is encoded while referring to the reference line signal LR.

For example, the encoded data has a white run length of 20
48, when valid data cannot be obtained, the level plane signal corresponding to the encoded data and level signal DP is not output.

However, even in that case, if the level signal DP interferes with the level plane output at the beginning of the unit block (in this case, the level plane of level 1), the level plane signal and encoded data are output.

On the other hand, if the encoded data includes valid data, a level plane signal and encoded data are output.

Therefore, the output format of encoded data in this embodiment is as shown in FIG.

That is, when the level plane consists of four.

When all four level planes contain valid data, the encoded data of the four level planes are output continuously as shown as the n line, and the valid code is output to the level plane of level 2. If no conversion data is included, as shown as the (n+1) line,
The encoded data of this level 2 level plane is omitted and output.

Furthermore, as shown as the (n+2) line, since the encoded data of at least the level plane of level 1 is output, line management can be carried out in an inconvenient manner.

In addition, in the present invention, ■ only the first output of the encoded data for the scanning line is set, and the arrangement order of the other level planes is not restricted, so as shown as (n+3) lines, 2 Even in such a case, where the order of the level planes subsequent to the level plane may be changed, each level plane can be easily identified because a level plane signal for identifying each level plane is added. In addition, since the order of the second and subsequent level planes is not restricted, when applied to a device that processes the image signals of each level plane independently and in parallel, encoding is performed in the order in which the processing is completed. Since data can be output, it is possible to speed up the encoding process.

FIG. 3 specifically shows the encoding processing section 3. As shown in FIG.

In the figure, the control section 31 first raises the line synchronization signal SY and requests the image processing section 2 to transfer data.

As a result, as described above, the level signal DP corresponding to the level plane outputted first from one image processing unit 2 is
This level signal D is output to the control section 31, and the control section 31 receives this level signal D.
Remember P.

Next, the control section 31 raises the initialization signal SI, initializes the change point detection two-dimensional encoding circuit 32, and resets the run timing counter 33.

When the change point detection two-dimensional encoding 32 is initialized, it outputs the shift clock SC to the image processing section 2 and the run length counter 33, and outputs the reference line signal LR and encoded line signal LC from the image processing section 2 bit by bit. and detects a change point in the encoded line signal LC, and performs two-dimensional encoding processing while referring to the contents of the reference line signal LR.

Further, the shift clock SC output at this time is counted by a run length counter 33.

When a change point is detected, the shift clock SC is stopped and a change point detection signal DD is output to the control section 31.

When the control unit 31 inputs the change point detection signal DD, if the encoding mode at that time is one-dimensional encoding mode (one-dimensional encoding processing), the control unit 31 inputs the output data of the run-length code table 34 as encoded data. , when the encoding mode is two-dimensional encoding mode, the change point detection two-dimensional encoding circuit 3
The encoded data SD output from 2 is input as encoded data.

Then, the control unit 31 raises the reset signal SR,
The change point detection two-dimensional encoding circuit 32 and run length counter 33 are reset. As a result, the count value of the run length counter 33 is reset to 0, and the change point detection two-dimensional encoding circuit 32 resumes its operation.

This operation is repeatedly executed until one level plane is completed, and when the processing for one level plane is completed, the control section 31 raises the line synchronization signal SY again and repeatedly executes the same process as described above. In that case, in the encoding process of the second and subsequent level planes in one scanning line, the encoded data may contain data that is not valid in one-dimensional encoding mode. When the data reaches the code word v(0), the level signal and encoded data of that level plane are not output.

Then, the control unit 31 repeatedly executes the above processing for each scanning line to process all images.

Note that the synchronization signal table 36 includes line end signal EOL.
The controller 31 stores predetermined synchronizing signals such as the following.The controller 31 reads out the stored data.

[Effects] As explained above, according to the present invention, encoded data for each unit block is output with encoded data of a predetermined level plane at the beginning, and encoded data that does not include valid data is omitted. Therefore, unnecessary encoded data is not output, and an encoding processing method with improved encoding efficiency can be realized.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an image information processing device according to an embodiment of the present invention, FIG. 2 is a signal arrangement diagram showing the output format of encoded data output by the device shown in FIG. 1, and FIG. Figure 3 is a block diagram showing a specific example of the encoding processing unit;
Fig. 4 is a signal arrangement diagram showing the output format of encoded data according to the one-dimensional encoding method, Fig. 5 is a signal arrangement diagram showing the output format of encoded data according to the two-dimensional encoding method, and Fig. 6 is a signal arrangement diagram showing the output format of encoded data according to the two-dimensional encoding method. FIG. 2 is a signal arrangement diagram showing a conventional example of an output format of encoded data. 2... Image processing unit, 3... Encoding processing unit, 31...
- Control unit, 32... Change point detection two-dimensional encoding circuit, 3
3... Run length counter, 34... Run length code table, 35... OR circuit, 36... Synchronization signal table. $7Figure 3Figure 2Figure 4Eot oc Eot oc EOt -■=
Prisoner Figure 5 Figure 6

Claims (1)

[Claims] The image information is read into multi-values, the read information is divided into multiple level planes consisting of information at the same level, and each level plane is encoded for each unit block, and the encoded data within the same unit block is continuous. In the encoding processing method that outputs the level plane, identification information for identifying the level plane is added to the beginning of the encoded data, the encoded data of a predetermined level plane is placed at the beginning of each unit block, and other An encoding processing method characterized by omitting encoded data of a level plane that does not include valid data.