JP2921685B2 - Image data correction device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image data correction device for correcting image data in which each pixel is represented by a binary value.

2. Description of the Related Art An image reading apparatus that obtains a black-and-white image by binarizing an image signal obtained by reading a document image line by line by a line image sensor and obtaining a black-and-white image is well known.

When reading an image of a fixed density with such an image reading apparatus, a part of the read image is affected by the unevenness of the light amount of the light source illuminating the original and the noise of the circuit for processing the image signal from the line image sensor. There was a case where the black and white of the pixel was reversed.

[Problems to be Solved by the Invention] Conventionally, when correcting an image which is partially black-and-white inverted, image data for one page is temporarily stored in an image memory, and data processing is performed by a microcomputer. I was

For this reason, there has been a problem that the configuration of the device for correcting the image information becomes complicated and the cost increases.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image data correction apparatus which solves the above-described problem, has a simple apparatus configuration, and can reduce cost.

[Means for Solving the Problems] For this purpose, the present invention provides a method of sequentially inputting image data by a fixed number of bits from the beginning of the first line and storing at least two lines immediately before input in a memory. Each time the image data is input, the image data of a certain number of bits at the same position one line before and two lines before are read out from the memory, and the image data just input and the image data two lines before the same are all the same number of bits each. If the value of the image data of the previous line is different from that of the other bits by one bit except the two bits at both ends, the one bit is corrected to the same value as the other bits, and It is characterized in that the corrected image data one line before is sequentially output as corrected image data.

[Operation] Since a large-capacity image memory for temporarily storing image data for one page and a microcomputer for performing data processing are not required, the configuration of the apparatus can be simplified and the cost can be reduced. become.

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

FIG. 1 is a block diagram showing an image data correcting apparatus according to an embodiment of the present invention. This image data correction device is provided in a facsimile device, corrects image data received and reproduced by an image receiving unit (not shown), and outputs the corrected image data to a plotter that records an image.

In the figure, a latch circuit 1 holds image data transferred from an image receiving unit for each byte. The buffer memory 2 is for sequentially inputting image data held by the latch circuit 1 and storing the immediately preceding two lines. The latch circuit and the latch circuit 4 hold the image data read from the buffer memory 2 one byte at a time.

The P / S (parallel / serial) conversion circuit 5 converts the image data held in the latch circuit 3 into a serial signal, and the selector 6 converts the serial signal and the image data corrected by a circuit described later. To choose. The determination table 7 is composed of, for example, a ROM (Read Only Memory) IC or a logic circuit, and determines whether or not data correction is necessary and in accordance with the bit pattern of each image data held in the latch circuits 1, 3, and 4. This is for determining data. The bit correction circuit 8 controls switching of the selector 6 based on the determination result, and outputs predetermined correction data as needed.

With the above configuration, when the facsimile apparatus (not shown) starts the receiving operation, the image data correcting apparatus
The image data of the page is sequentially input one byte at a time from the first line to the last line.

The latch circuit 1 holds input image data, and the buffer memory 2 sequentially stores the image data.

Then, 2 when the line of image data is to be input, the latch circuit 1 in synchronism with the timing of outputting the byte by byte image data D _2, the buffer memory 2, the first line of 1 byte in the same position outputs the image data D _1, the latch circuit 3 holds the image data D _1.

P / S conversion circuit 5 converts the image data D ₁ into a serial signal. The selector 6 is usually has selected the P / S conversion circuit 5 side, and outputs to a plotter (not shown) the image data D ₁ that has been converted into the serial signal. Thus, the received image of the first line is recorded by the plotter.

Next, when the image data of the third and subsequent lines comes to be input, the operation of correcting the image data is started as shown in FIG. That is, assuming that one byte of the image data of the line i is input (process 101), the buffer memory 2 outputs the one-byte image data _Di-1 at the same position one line before, as described above. At the same time, 1-byte image data _Di-2 at the same position two lines before is output. Then, the image data D _i-1 is a latch circuit 3, the image data D _i-2 latch circuit 4 holds each (process 102).

Next, the determination table 7 determines that the image data _Di , D
_The following determination is made for _i-1 and _Di-2 . That is, first, to check the image data D _i-2 of the line i-2 (Y of process 103) (processing 103), and all bits of the byte is all "0" or all "1", the following Check image data D _i of line i (the processing 104).

In the image data D _i is all "0" or all "1",
If the value is different from the image data _Di-2 (step 104
Y) Then, the image data Di-1 of the line i _-1 is checked (process 105). Here, if only one bit of the byte has a different value from the other 7 bits (Y in step 105), then the position of the bit having a different value is checked (step 10).
6).

If the bit is within 6 bits from the second bit to the seventh bit in one byte (Y in process 106), the one bit in the image data _Di-1 is determined to be an error bit. . For example, when the other bit is “1”, the one bit is corrected to “1”, and the other bit is set to “0”.
At this time, a predetermined correction signal to be corrected to “0” is output to the bit correction circuit 8.

When the correction signal is input, the bit correction circuit 8 switches the selector 6 to the bit correction circuit 8 side, and outputs one byte of all “0” or all “1” data. Thus, the image data D _i-1 to the corrected line i-1 from the selector 6 is output to the plotter, not 1 byte shown (above, process 107).

By the above operation, for example, as shown in FIG. 3A, when the image data is inverted by one bit in one line at the boundary between the white image and the black image, as shown in FIG. It will be corrected.

On the other hand, in the above case, when one byte of the image data _Di-2 is not all "0" or all "1" (N in the processing 103), the image data _Di is similarly all "0" or all "1". If it is not "1" or has the same value as the image data _Di-2 (N in process 104), or if all the bits of the image data _Di-1 have the same value or two or more different bits (processing
If (N in 105) and there are no bits having different values in the middle 6 bits (N in process 106), the determination table 7 does not output the correction signal. In this case, the bit correction circuit 8
Holds the selector 6 in a state where the P / S conversion circuit 5 side is selected. Thus, the image data D _i-1 of line i-1 is output as it is to the platter (processing 108).

Now, for example, as shown in FIG.
Receiving an image in which _two pixels e ₁ and e _{2 of} −1 are inverted,
With this device, the image data of each line is converted into B _j , B _{j + 1} ,
It is assumed that the determination is sequentially performed for each byte, such as B _{j + 2} . Then, the image data of line i-1 is bytes _Bj and B
when _{j + 2,} are respectively the pixel e ₁ and the e ₂ is corrected, the plotter will correct the image as shown in FIG. 5 (b) is recorded.

As described above, if there is a pixel that has been inverted in black and white on the straight line in the main scanning direction or in the portion of the image, the pixel is corrected, and a natural image can be obtained.

Further, in the present embodiment, the apparatus is configured only with simple hardware without using a large-capacity image memory or microcomputer as in the related art. This simplifies the configuration of the device and reduces its cost.

In the above-described embodiment, as described in FIG.
When the image data of the line i and the line i-2 are all "1" and all "0", the image data of the line i-1 is corrected, but the image data of the line i and the line i-2 are corrected. But,
If both are all “1” or all “0”, the bit correction of the image data may be similarly performed. In this case as well, the image correction as shown in FIG. 4 can be executed in the same manner, and as shown in FIG.
One inversion or have pixels e ₃ that, when there is 1 pixel e ₄ in the black image, as shown in FIG. (B), so that they are corrected.

In the above embodiment, the image data of each line is 1
The checks are sequentially performed while shifting the bytes, and in each check, the inversion of the bits at both ends of one byte is ignored, so that the bits at both ends cannot be corrected. Therefore, when one byte is checked so as to correct the bits at both ends, one bit is shifted in the same manner.
If byte checking is performed, correction can be performed for all bits.

[Effects of the Invention] As described above, according to the present invention, image data is sequentially input by a fixed number of bits, and two lines input immediately before are stored in the memory. The state of the image data, the image data of the previous one line and the image data of the previous two lines is determined, and if a predetermined condition is satisfied, a predetermined bit correction is performed on the image data of the previous line to correct the image. Since it was taken out as data,
The configuration of the device is simplified, and its cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram of an image data image data correcting apparatus according to one embodiment of the present invention, FIG. 2 is an operation flowchart showing image data correction processing, and FIG. 3 shows an example of image data to be corrected. FIG. 4 is an explanatory diagram showing an example of a received image to be corrected, and FIG. 5 is an explanatory diagram showing an example of a received image corrected in another embodiment. 1,3,4 ... Latch circuit, 2 ... Buffer memory, 5 ... P
/ S (serial / parallel) conversion circuit, 6 ... selector,
7... Judgment table, 8... Bit correction circuit.

Claims (1)

(57) [Claims] An image data correcting apparatus for correcting image data for each line composed of binarized pixels according to pixel states of preceding and succeeding lines, without overlapping image data from the head of the i-th line. Further, image data input means for taking out all the bits at a constant rate without skipping and sequentially inputting them, and (i-1), (i) input immediately before the currently input i-th line of image data -2) a memory for storing image data for two lines of lines, and every time a fixed number of bits of image data for the i-th line are input (i
-1) image data reading means for reading out image data of a fixed number of bits at a position corresponding to the line and (i-2) th line from the memory; Read out from the memory (i-
2) The image data of the fixed number of bits corresponding to the line are all the same value, and both ends of the image data of the fixed number of bits corresponding to the line (i-1) read out from the memory. One bit excluding two bits is to be inspected, and the condition is that only the one bit has a different value from the other pixels of the corresponding fixed number of bits of the (i-1) th line. Data correcting means for correcting the image data to the same value as the other pixels, and selecting whether to correct and output the image data of the (i-1) th line by the image data correcting means or to output as it is, and sequentially. An image data correction device, comprising: image data output means for outputting.