JPH06261216A - Image processor - Google Patents

Abstract

PURPOSE:To provide an image processor which is capable of performing the image data processing when image data of a prescribed line without error generation in place of the error generation line is made to be printed and outputted by a page printer at high speed when an error occurs in the decoding processing of image data. CONSTITUTION:This processor is provided with the decoding means 1a of encoded image data and a means 1b successively storing the decoded image data in a page memory 2 for page printer P. When an error occurs in the decoding processing of image data, the image data of the line before or after an error generation line is read from the page memory 2 and the image data is stored in the page memory 2 in place of the image data of the error generation line.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus applied to a facsimile machine or the like, and more particularly to decoding coded / compressed image data and then printing the image data on a recording paper by a page printer. The present invention relates to a printout type image processing apparatus.

[0002]

2. Description of the Related Art In a facsimile machine, image data to be communicated by facsimile is subjected to one-dimensional coding or two-dimensional coding, and the amount of data is compressed. Therefore, in order to print out the image data received by facsimile with the printer, it is necessary to decode the encoded image data in advance. On the other hand, in facsimile communication, the bit of the image data may be inverted due to the adverse effect of noise on the line on the transmitted and received image data. Such image data is not proper, and if the decoding process is performed as it is, for example, it is originally 1
The line bit number (black and white pixel number) is 17 for A4 document width.
An error occurs in the decoding process because the number of bits that should be 28 bits is different from that.

When the above error occurs,
It is possible to cope with this by not printing out the image data of the line in which the error has occurred, and repeatedly printing out the image data of one line before that line twice. However, such processing can be relatively easily performed by a printer such as a thermal printer that prints out image data on a line-by-line basis, but a page printer needs to create image data for one page in advance. Therefore, it is not easy to re-record the image data of one line before.

Therefore, conventionally, as a method for coping with a page printer, when an error occurs in the decoding process of the image data, the image data of the line immediately preceding the line in which the error has occurred is repeated again. Then, the decoded image data is stored in the page memory instead of the image data of the error occurrence line.

[0005]

However, in the above-mentioned conventional method, since the image data of the same line is repeatedly decoded twice, the first decoding is performed when the second decoding is performed. The image data of the line immediately before the error after the decoding process of the second time is completed is EOL from the image data in the encoded state in which the data length of one line is not constant.
It is necessary to detect and read the signal. Therefore, it takes a long time to search / read out the corresponding line, and it is difficult to start high-speed processing of image data and quick printout.

The present invention has been proposed in view of the above points, and when an error occurs in the decoding process of image data,
Instead of the error occurrence line, the data processing speed when performing image data processing so that the image data of a predetermined line in which no error has occurred is printed out by the page printer, and the image data printout start time is accelerated. It is an object of the present invention to provide an image processing device capable of performing the above.

[0007]

SUMMARY OF THE INVENTION An image processing apparatus according to the present invention, which has been proposed to achieve the above object, has a decoding means for encoded image data and a decoded image data for a page printer. An image processing apparatus having means for sequentially storing in a page memory, wherein when an error occurs in a decoding process of image data, the image data of a line before or after an error occurrence line is read from the page memory. The image data is stored in the page memory instead of the image data of the error occurrence line.

[0008]

In the image processing apparatus according to the present invention having the above-mentioned structure, the image data in the encoded state is decoded by the decoding means, and the decoded image data is sequentially stored in the page memory. . When an error occurs in the decoding process, a predetermined line before or after the line in which the error has occurred is selected from the image data stored in the page memory after the decoding process has been completed. Image data is read. Then, the read image data is stored in the page memory instead of the image data of the error occurrence line. Therefore, if the image data of each line stored in the page memory is printed out by the page memory, it is possible to obtain an image of good quality without any error occurrence line.

In the above series of processing, it is necessary to read the image data of a predetermined line located before or after the error occurrence line from the image data stored in the page memory. The image data stored in the page memory has already been decoded and has a fixed data length (in general, addressing is also performed for each line). . Therefore, the search / read processing of the predetermined line located before or after the error occurrence line is compared with the case where the predetermined line is searched from the image data in the encoded state where the data length is not constant. It's fairly easy and can be done at high speed. Further, after the image data on the predetermined line is searched, the copying process may be performed by simply storing the image data at a predetermined address in the page memory as it is, so that such a process is also easy and a high speed process is possible.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an example in which the image processing apparatus according to the present invention is applied to a facsimile apparatus F. This image processing apparatus includes an electrophotographic page printer P, a hard codec 1 for processing image data to be printed and output by the page printer P into a predetermined state, which will be described later, and the hard codec 1. A page memory 2 for storing image data transmitted to the page printer P. Here, the page printer P creates an electrostatic latent image on the photosensitive drum 12 by exposing the photosensitive drum 12 charged by the charger 11 from the optical writing unit 13 including an LED array head. After that, the developing device 14 performs development with toner. After the electrostatic latent image is developed, the transfer device 15 causes the developed image to be transferred onto the recording sheet K, and then the heater 17 of the fixing unit 16 is used.
The transfer image on the recording paper K is fixed by the method. still,
In the figure, reference numeral 18 denotes an eraser lamp for removing the charge of the photosensitive drum 12 and repeatedly using the photosensitive drum 12. Reference numeral 19 denotes a memory removal brush for redeveloping the toner remaining on the photosensitive drum 12 on the photosensitive drum 12.

The hard codec 1 controls C for controlling each part of the image processing apparatus and other facsimile apparatus F.
A signal processing unit 4 including a PU, a ROM 5 and a RAM 6 functioning as a system memory, an image memory 7 for storing image data in a coded / compressed state, a modem 8a, a line control unit 8b, and the like. The facsimile communication control unit 8 for executing the facsimile communication via L, the other operation unit 9, the image reading unit 10, and the like are connected via a data bus 3 and a control bus (not shown). The hard codec 1 is composed of both the encoding / decoding conversion circuit 1a and the data control unit 1b. One of the encoding / decoding conversion circuits 1a includes an image reading unit 1
The image data obtained by reading and scanning the original image at 0 is encoded, and the image data in the encoded state read from the image memory 7 or received by the facsimile communication control unit 8 is decoded. It is a thing.

On the other hand, the data control unit 1b executes the writing process while sequentially addressing the image data decoded by the encoding / decoding conversion circuit 1a into the page memory 2, but in addition to the following: It also has various control functions. That is, when an error occurs in the decoding process at the stage of executing the decoding process in the encoding / decoding conversion circuit 1a, the data control unit 1b stores the image data of the error occurrence line in the page memory 2 It is not written in and is discarded. Then, the image data of the line immediately before the error occurrence line is read from the page memory 2, and the read image data is controlled to be written in the address area of the page memory 2 where the original error occurrence line should be written. There is. The reading of the image data from the page memory 2 may be executed by the signal processing unit 4,
Further, it may be executed by a DMA controller (not shown) other than that.

Next, the operation of the image processing apparatus having the above configuration will be described. First, in order to print out the image data received from the external facsimile device by the facsimile communication control unit 8 of the facsimile device F on the recording paper K by the page printer P, after decoding the received image data in the encoded state, It is necessary to store one page of image data in the page memory 2. In such processing, the received image data is transmitted in order from the first line in the form of a serial signal to the encoding / decoding conversion circuit 1a, and the image data decoded by this circuit 1a is shown in FIG. 2 (a). So that the page memory 2 has the first
It is sufficient to write sequentially from the image data on the line.

However, the bit of the image data may be inverted due to the noise of the line L during the facsimile communication. In such a case, an error occurs in the decoding of the Nth line in which the bit is inverted. When such a decoding error occurs, the data control unit 1b discards the image data of the Nth line without writing it in the page memory 2. Then, as shown in FIG. 2B, the data control unit 1b reads the image data of the (N-1) th line located immediately before the Nth line in which the error has occurred, and directly reads the image data. Write to be copied in the memory area of the line.

The image data stored in the page memory 2 has already been decoded to make the data length constant (for example, A
Since the width is 1728 bits and the address is specified, the process of searching and reading the image data of the (N−1) th line from the page memory 2 is performed as shown in FIG. 2B. It can be executed at high speed. Further, the copying process after the reading is also easy. Therefore,
Even if a decoding error occurs, page memory 2
Thus, it is possible to perform the processing of expanding the image data having no error for one page at high speed. Steps 100 to 107 of the flowchart of FIG. 3 show the above-described series of operation procedures (note that n in the flowchart of FIG. 3 is a variable, and the concept is different from N in FIG. 2).

When the storage of the decoded image data for one page is completed as described above, thereafter, the image data of each line written in the page memory 2 is sequentially read out, and then the page printer P is read. Just send it. As a result, it is possible to obtain a recorded / reproduced image with good image quality in which the image data of the (N−1) th line is continuously printed twice instead of the image data of the Nth line in which an error has occurred. Become.

In the above embodiment, when the image data decoding error occurs, the image data of the line immediately before the error occurs is copied, but the present invention is not limited to this. For example, for a line in which a decoding error has occurred, an empty memory area is provided in the page memory 2 so that only the image data that is decoded without error can be stored in the page memory 2 for one page and then The image data of the previous line may be copied and written in an empty memory area corresponding to the error occurrence line. Further, in such a case, as shown in FIG. 2, when the N-th line is an error occurrence line, the (N
The image data of the (+1) th line may be copied to the page memory 2 instead of the error occurrence line. In addition, the image processing apparatus according to the present invention is not limited to the application to the facsimile apparatus, and can be applied to various applications for printing out encoded image data.

[0018]

As can be understood from the above description, in the image processing apparatus according to the present invention, when an error occurs in the decoding process of encoded image data, the decoding process is already completed and the page Since the image data of the predetermined line stored in the memory is read and copied, the image data of the predetermined line can be read out from the image data in the encoded state which is not decoded as in the past. Compared with the case of decoding, the image data can be read at a considerably high speed, and the read image data can be efficiently stored in the page memory instead of the image data of the error occurrence line. Therefore, in the present invention, it is possible to perform at high speed the image data processing that enables the page printer to print out the image data of a predetermined line in which an error does not occur, instead of the error occurrence line, and the image printing by the page printer is performed. The special effect that the output time can be advanced is obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of a hardware configuration when an image processing apparatus according to the present invention is applied to a facsimile apparatus.

2A and 2B are explanatory views showing an example of data storage processing in a page memory in the image processing apparatus according to the present invention.

FIG. 3 is a flowchart showing an example of an operation procedure of image data processing in the image processing apparatus according to the present invention.

[Explanation of symbols]

 1 hard codec 1a encoding / decoding conversion circuit 1b data control unit 2 page memory 4 signal processing unit 8 facsimile communication control unit 8a modem P page printer K recording paper F facsimile machine

Claims (1)

[Claims] 1. An image processing apparatus comprising: a decoding unit for encoded image data; and a unit for sequentially storing the decoded image data in a page memory for a page printer, the image data decoding process. When an error occurs, the image data of the line before or after the error occurrence line is read from the page memory and the image data is stored in the page memory instead of the image data of the error occurrence line. Image processing device.