JPH01223879A - Expansion processing unit for compressed code data - Google Patents

Abstract

PURPOSE:To shorten the expansion processing time by providing a buffer clear circuit and an address counter control circuit and completing the processing by the countup of the address counter only when the image data by one line all corresponds to white level. CONSTITUTION:When a code data representing all of one line corresponding to a white level is inputted, since no change point exists, no change point position address is written in a line memory 4. When a control section 5 detects it from the change point information that all one line is at a white level, an output section 6 does not apply generating/transfer processing to an image data and a command is given from the control section 5 to a counter control section 9 to increment the count of an address counter 8 by one line. Thus, the same result that a data of full '0' level is written sequentially in an image buffer 7 by one line is obtained. After the processing, the expansion processing of the succeeding line is transited. Thus, the expansion processing time is shortened and it is possible to write the decoded image data into the image buffer at a high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an apparatus for decompressing compressed code data, and more specifically, for decompressing compressed image data to decode it into image data. The present invention relates to a compressed code data decompression processing device including means for writing data into an image buffer.

(Prior Art) Fig. 2 shows a configuration explanatory diagram of a conventional decompression processing device, in which 1 is an input section for compressed code data, 2 is a decoding table, 3 is a black and white change point detection circuit, and 4 is a line A memory, 5 is a control section, 6 is an output section, 7 is an image buffer for storing decoded image data, and 8 is an address counter.

Next, the operation of this conventional device will be explained using FIG. 2.

Modified Huffman (MH) method, Modified Read (MR) method, Modified Ml ((MMR)
When code data compressed by the method is input to this device with a certain bus width, the input unit 1 cuts out the compressed code data into one code unit and sends it to the decoding table 2, where information such as run length etc. is converted to The change point position detection circuit 3 calculates a change point position address from this information, and the control section 5 writes the address into the line memory 4. This line memory 4 is designed to be able to write data for at least one line. After data for one line is written to the line memory 4, the control unit 5 sequentially reads it and outputs change point position address information to the output unit 6.
to notify. The output unit 6 generates decoded image data in units of bus width based on this information, writes it into the image buffer 7, and increments the address counter 8 for each output.

(Problem to be Solved by the Invention) However, in such conventional decompression processing devices, the amount of image data is large, ranging from several times to several tens of times the amount of code data, so transferring the image data takes up the decompression processing time. The problem was that they accounted for the majority.

SUMMARY OF THE INVENTION An object of the present invention is to provide a decompression processing device that can shorten decompression processing time and write decoded image data to an image buffer at high speed.

(Means for Solving the Problems) The present invention provides a means for decompressing compressed code data to generate uncompressed image data and writing this image data to an image buffer. The processing device is provided with a buffer clear circuit that clears the memory of the image buffer to 0 degrees when the device is started up, and an address counter control circuit. Does not generate or transfer image data,
This is a compressed code data decompression processing device (hereinafter sometimes referred to as the device of the present invention) characterized in that the processing is completed only by counting up an address counter.

(Function) The buffer clear circuit included in the device of the present invention has the function of clearing the memory in the image buffer when the device is started up.

Furthermore, when all of the image data for one line corresponds to white, the address counter control circuit stops writing from the output section to the image buffer and only counts up the address counter, thereby increasing the time required for data transfer. It has the effect of shortening.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a configuration explanatory diagram showing an embodiment of the apparatus of the present invention, in which parts having the same functions as those in FIG. 1 are designated by the same numbers. In the figure, 9 is a counter control unit that increases the value of the address counter 8 by a specified value according to a command from the control unit 5, and 10 is an image buffer 7.
This is a buffer clear circuit that clears all data to "o".

Next, the operation of the apparatus of the present invention having the configuration shown in FIG. 2 will be explained, focusing on the differences from the operation of the conventional apparatus described above.

The device of the present invention is usually used by being incorporated into a system such as a facsimile machine. Utilizing the time from the startup of the system to the start of decompression processing, the image buffer is cleared to zero in advance by the buffer clear circuit 10.
“Please clear it.

When the decompression process starts, basically the same process as in the example of FIG. 2 is executed. That is, a change point position address is calculated from the input code data, the address is written in the line memory 4 for one line, the control section 5 reads out the address, and the change point information is notified to the output section 6. The output unit 6 generates decoded image data in units of bus width based on this information, writes it into the image buffer 7, and increments the address counter 8 for each output.

By the way, in the above processing process, if code data corresponding to all of one line is inputted is white, there is no changing point, so no changing point position address is written in the line memory 4. In the conventional apparatus, image data corresponding to this case (one line all "0") is sequentially generated and written to the image huffer, and at the same time, the address counter 8 is sequentially counted up. On the other hand, in the device of the present invention, when the control section 5 detects from the change point information that one line is entirely white, the output section 6 does not perform image data generation/transfer processing, and the control section 5 performs counter control. A command is issued to section 9 to increase the count value of address counter 8 by one line. In this way, the same result as if all the data "'○"' were sequentially written into the image buffer 7 for one line is obtained. After this process, the process moves on to the next line expansion process.

(Effects of the Invention) As described in detail above, according to the present invention, since a counter control section and a buffer clear circuit are newly provided, if the image buffer is cleared to O before decompression processing, If data corresponding to all white for one line is manually generated, the same result as sequentially generating and transmitting image data can be obtained by simply incrementing the address counter without generating and transmitting the image data for that line. Obtainable. Therefore, the amount of image data to be generated and transferred can be reduced, and the decompression processing time can be shortened.

In normal decompression processing, a state in which all lines are white frequently occurs, so it can be said that the effect of reducing processing time by the present invention is extremely large.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the configuration of the device of the present invention, and FIG. 2 is an explanatory diagram of the configuration of the conventional device. 8...Address counter, 9...Counter control unit. Patent applicant Oki Electric Industry Co., Ltd.

Claims (1)

[Scope of Claims] A compressed code data decompression processing apparatus comprising means for performing decompression processing on compressed code data to generate uncompressed image data and writing this image data into an image buffer. A buffer clear circuit that clears all of the memory to "0" at device startup and an address counter control circuit are provided, and when all of the image data for one line corresponds to white, image data generation and transfer processing is provided. A compressed code data decompression processing device characterized in that the processing is completed only by counting up an address counter without performing any processing.