JP2621791B2 - Facsimile machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a facsimile apparatus for removing an isolated point and performing idle conveyance (white line skip) without printing in the sub-scanning direction to shorten the printing time.

[0002]

2. Description of the Related Art FIG. 6 is a block diagram showing a configuration example of a reception signal processing system of a conventional facsimile apparatus. In FIG. 6, in this example, a facsimile message signal received through a line, a communication control device, or the like (not shown) is input to the demodulation unit 1. This signal is demodulated by a demodulation unit 1 and further decoded by a decoding unit 2
Is decrypted. The decoded binary image data is subjected to smoothing processing by the smoothing processing unit 3 as needed. Further, the reduction processing operation unit 4 performs reduction processing as needed. In the binary image data output from the reduction processing operation unit 4, a white line is detected by a white line detection unit 8. Thereafter, the printing unit 9 prints the facsimile message by skipping the white line in the detected binary image data, and outputs the facsimile message paper.

In such a facsimile apparatus, an isolated point is also removed from an input signal obtained by reading written information from a facsimile electronic paper. For example, in an "image signal processing circuit of a facsimile apparatus" disclosed in Japanese Patent Application Laid-Open No. 60-249472, a threshold value for determination of isolated point processing is determined based on an average value of levels of pixels around a target pixel. The isolated point can be reliably removed regardless of the background level of the document and the shading of characters and the like.

[0004]

However, in the former case of the above-mentioned conventional example, the white line can be detected by reading in the main scanning direction by the white line detecting section 8 if an isolated point is included in one of the lines. Absent. That is, since the printing skip operation is not performed in the printing unit 9, the printing time cannot be reduced.

[0005] An example of the official gazette is to remove an isolated point from an input signal obtained by reading the description information from a facsimile electronic message paper, and to reduce the pseudo-halftone printing deterioration of the received facsimile electronic message data (image data). And cannot be applied to obtain high-quality printing.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and it is possible to reliably remove isolated points in received facsimile electronic mail data, to perform short-time printing by white line skipping, and to obtain high-quality images without noise. It is an object of the present invention to provide a facsimile apparatus which enables printing, and furthermore, separates an image area to prevent deterioration of pseudo halftone printing.

[0007]

In order to achieve the above object, a facsimile apparatus according to claim 1 performs a logical operation on an image signal pattern of a peripheral pixel with respect to a target pixel in received facsimile binary data, and determines whether the target pixel is an isolated point. An isolated point removing means for removing the isolated point when it is determined that the original pixel density is smaller than a threshold value set in advance and the first density is lower when the density of the surrounding pixel is lower than a preset threshold value. An image area separation selecting means for outputting a selection signal and outputting a second selection signal in the case of a halftone area where the surrounding pixel density is high, and selecting image data from the isolated point removing means with the first control signal And a selecting means for selecting and outputting the target pixel data with the second control signal.

According to a second aspect of the present invention, in the facsimile apparatus, the isolated point removing means delays the plurality of line signals of the binary image data so as to be synchronized with the first line signal in the plurality of lines. A plurality of delay circuits; a second plurality of delay circuits for adjusting the plurality of pixel column signals on the plurality of lines to the same time as the pixel line signals on the first line;
And an isolated point removal logic operation unit that performs a logical operation on the pattern of the image signal from the plurality of delay circuits and removes the isolated point when the pixel of interest is determined to be an isolated point.

According to a third aspect of the present invention, in the facsimile apparatus, the image area separation / selection means delays a plurality of line signals of the binary image data and adjusts them to the same time as the first line signal in the plurality of lines. A plurality of delay circuits, a second plurality of delay circuits for adjusting a plurality of pixel column signals on a plurality of lines at the same time as the pixel line signals on the first line, and a first and a second plurality of delay circuits A black pixel adder for calculating the original density of the surrounding pixels from the image signal from the image forming apparatus, a threshold setting unit for setting a threshold value for comparison with the original density obtained by the black pixel adder, A comparator that outputs a first selection signal when the density of the original from the device is smaller than the threshold value and the density of the surrounding pixels is low, and outputs a second selection signal when the density of the surrounding pixel is halftone. This is a configuration including:

According to a fourth aspect of the present invention, the facsimile apparatus obtains the document density by the black pixel adder from the total number of black pixels of surrounding pixels.

A facsimile apparatus according to a fifth aspect is configured to use a flip-flop circuit as a preferable delay circuit.

[0012]

The facsimile apparatus according to any one of the first to fifth aspects of the present invention performs isolated point removal when the document density calculated from the surrounding pixels of the target pixel is smaller than the threshold value and the surrounding pixel density is low. In the case of a halftone area where the surrounding pixel density is high, the pixel data of interest is output.
Printing is performed skipping the white line. Therefore, isolated points when characters and halftones are mixed are reliably removed. Further, the printing time can be shortened by the white line skip, and high quality printing without noise can be obtained. Also,
Deterioration of pseudo halftone printing is prevented.

[0013]

Next, an embodiment of the facsimile apparatus of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an embodiment of the facsimile apparatus of the present invention. In FIG. 1, this example is a reception signal processing system of a facsimile apparatus, which demodulates a facsimile message signal received through a line, a communication control device, and the like (not shown), and decodes a demodulation signal from the demodulation section 11. The decoding unit 12, a smoothing processing unit 13 that performs smoothing processing on the image data from the decoding unit 12, and a reduction that outputs the binary image data Sa that has been subjected to the reduction processing operation processing on the image data from the smoothing processing unit 13 A processing operation unit 14 is provided.

Further, in this example, an isolated point removing unit 15 that performs a logical operation from the pixel of interest and its surrounding pixels to remove an isolated point, and calculates the document density of the surrounding pixels as described below. An image area separation unit 16 that compares the image signal with a preset threshold value and outputs a selection signal Sc based on the comparison;
A selection circuit 17 for selecting one of the signal from the isolated point removing unit 15 and the signal from the reduction processing operation unit 14 by the selection signal Sc from the image area separation unit 16 is provided. Further, a white line detection unit 18 for detecting a white line of the image data output from the selection circuit 17 and a facsimile electronic paper which prints the image data from the white line detection unit 18 by skipping the white line are output. A printing unit 19 is provided.

FIG. 2 is a block diagram showing a detailed configuration of the isolated point removing unit 15. In FIG. 2, the isolated point removing unit 15 includes one line for delaying one line (one line for reading a facsimile electronic message) of the binary image data Sa from the reduction processing operation unit 14 under the control of the line memory control unit 30. A delay memory 21 and a two-line delay memory 22 for delaying two lines are provided. Further, flip-flop (F / F) circuits 23a and 23b to which the binary image data Sa from the reduction processing operation section 14 are supplied, and F / F circuits 24a and 23 to which the image data from the one-line delay memory 21 are supplied. 24b, F / F circuits 25a and 25b to which image data from the two-line delay memory 22 are supplied, an isolated point removal logic operation unit 28 for calculating the document density BL, and a one-line delay memory 21 and two-line delay And a line memory control unit 30 for controlling the two-line delay memory 22 to be operated.

FIG. 3 is a block diagram showing a detailed configuration of the image area separating section 16. As shown in FIG. 3, the image area separating unit 16 includes a one-line delay memory 31 for delaying one line of the binary image data Sa from the reduction processing operation unit 14, and a two-line delay memory 32 for delaying two lines. And F / F circuits 33a, 33b... 33n to which the binary image data Sa from the reduction processing operation section 14 are supplied. further,
F to which the image data from the one-line delay memory 31 is supplied
34n, and F / F circuits 35a, to which image data from the two-line delay memory 32 are supplied.
35b, 35n, a black pixel adder 36 for obtaining a document density from the number of black pixels of peripheral pixels extracted by the F / F circuits 33a to 35n, a threshold value setting unit 37, and a document density from the black pixel adder 36 And a line memory control unit 39 for controlling the one-line delay memory 31 and the two-line delay memory 32. ing.

Next, the operation of this embodiment will be described. First, the overall operation will be described. In FIG. 1, a facsimile message signal from a line, a communication control device, or the like (not shown) is input to the demodulation unit 11. This demodulation unit 11
The demodulated signal demodulated in is input to the decoding unit 12 and decoded. The decoded binary image data is subjected to smoothing processing by the smoothing processing unit 13 as needed.

An output signal from the smoothing processing unit 13 is input to a reduction processing operation unit 14, and a reduction processing operation is performed as necessary. The binary image data Sa of the reduction processing operation unit 14 is input to the isolated point removal unit 15, the image area separation unit 16, and the selection circuit 17. The isolated point removing unit 15 performs a logical operation on the image signal pattern of the target pixel and its surrounding pixels (m lines × n columns) to remove the isolated points. Image area separation unit 1
In step 6, the document density BL of the surrounding pixels (p lines × q columns) is calculated by the following equation (1).

BL = Σ (number of black pixels of surrounding pixels)... Total number of black pixels of surrounding pixels (1)

The signal indicating the document density BL and a threshold value previously set in the threshold value setting unit 37 are compared with the image area separating unit 1.
Compare with 6. If the comparison indicates that the document density BL is smaller than the threshold value, the surrounding density is low and the image data signal is the binary image data area or the background area, and the selection signal for selecting and outputting the image data signal from the isolated point removing unit 15. Sc is defined as the image area separating unit 1
6 to the selection terminal SEL of the selection circuit 17.

If the document density BL is greater than or equal to the threshold value in the comparison by the image area separating section 16, the surrounding density is high and the area is a halftone area, and the selection signal Sc is output from the image area separating section 16. The image data is sent to the selection terminal SEL of the selection circuit 17, and the selection circuit 17 selects and outputs the original image data of the target pixel from the reduction processing operation unit 14. This selection circuit 17
, The white line is detected by the white line detection unit 18, the printing unit 19 performs the skip processing, and outputs the printed facsimile electronic paper.

Next, the detailed operation of the isolated point removing unit 15 will be described. Here, a description will be given assuming that pixels are three lines and three columns (3 × 3). 4 (a), (b), (c), (d), and (e)
FIG. 5 shows an input pixel a and a target pixel b.
The input pixel a shown in (a) to (e) and the pixel of interest (b)
Are shown. The coordinates (1, 1) are the target pixel b, and the coordinates (0, 0), (0, 1), (0, 2), (1,
0), (1, 2), (2, 0), (2, 1), (2,
2) is a surrounding pixel for referring to the target pixel (b). The pixel of interest (1,1) and the surrounding pixels at coordinates (0,0) to (2,2) are separated by the isolated point removing unit 15.
To determine whether the target pixel is an isolated point, and if so, outputs the isolated point removal processing data from the selection circuit 17.

The isolated point removing unit 15 includes a reduction processing operation unit 14
Is input to the isolated point removal logic operation unit 28. Further, the binary image data Sa is transmitted to the F / F circuit 2
The signal is input to the isolated point removal logical operation unit 28 through each of 3a and 23b. One line of the binary image data Sa is
Delayed through the one-line delay memory 21 controlled by the line memory controller 30, the isolated point removal logical operation unit 28
Is input to Further, the one-line delay signal is F /
The signal is input to the isolated point removal logic operation unit 28 through each of the F circuits 24a and 24b. Further, two lines of the binary image data Sa are controlled by the line memory control unit 30.
Delayed through the line delay memory 22. The two-line delay signal is input to the isolated point removal logic operation unit 28 through the F / F circuits 25a and 25b.

Since the previous line and the previous pixel do not exist at the time of processing the first pixel, the one-line delay memory 21,
Two-line delay memory 22 and F / F circuits 23a to 25b
Must be reset to 0 (white pixel). F /
The F circuits 23a to 25b generate three columns of data delayed by one pixel at a time, and the three lines and three columns shown in FIGS.
The image signal for the pixel is input to the isolated point removal logic operation unit 28. The isolated point elimination logical operation unit 28 performs a logical operation of isolated point elimination from these data to determine whether the target pixel is an isolated point, and outputs isolated point elimination processing data if the pixel of interest is an isolated point.

Next, the detailed operation of the image area separating section 16 will be described. Binary image data S from the reduction processing operation unit 14
a is input to the black pixel adder 36. Further, the binary image data Sa is input to the black pixel adder 36 through each of the F / F circuits 33a, 33b,. One line of the binary image data Sa is delayed through the one-line delay memory 31 controlled by the line memory control unit 39, and F /
The signal is input to the F circuit 34a. The delay signal from the F / F circuit 34a is input to the black pixel adder 36 through each of the F / F circuits 34b to 34n. Further, two lines of the binary image data Sa are delayed through the two-line delay memory 31 controlled by the line memory control unit 39, and the two-line delay signal is input to the F / F circuit 35a.
The delay signal from the F / F circuit 35a is
35n are input to the black pixel adder 36.

Since the previous line and the previous pixel do not exist during the processing of the first pixel, the one-line delay memory 31,
Two-line delay memory 32 and F / F circuits 33a to 35n
Must be reset to 0 (white pixel). F /
Delayed one pixel at a time by the F circuits 33a to 35n,
Generate 6 minute data. Thereafter, the number of black pixels of the surrounding pixels (3 × 16) is added by the black pixel adder 36 according to the above equation (1). The added document density BL (0 ≦ BL ≦
48) and the value th (0) set in the threshold setting unit 37.
≦ BL ≦ 48) in the comparator 38.

If the result of this comparison is that BL ≧ th, the document density BL of the surrounding pixels exceeds the threshold value th, so that isolated point removal is not performed. The comparator 38 outputs a high-level “1” selection signal Sc to the selection terminal SEL of the selection circuit 17 so that the selection circuit 17 does not select the output signal from the isolated point removing unit 15. Also, if the result of the comparison is BL <t
In the case of h, the surrounding pixels are determined to be a binary character portion or a background portion because the document density BL is smaller than the threshold th.
Therefore, isolated point removal is performed. The comparator 38 outputs a selection signal Sc having a low level “0” for the selection circuit 17 to select the output signal from the isolated point removing unit 15.
7 is output to the selection terminal SEL.

Next, a detailed operation of the selection circuit 17 will be described. In FIG. 1, the output data of the isolated point removal logic operation unit 28 output from the isolated point removal unit 15 is input to the input terminal A of the selection circuit 17. The original data of the target pixel is input to the input terminal B of the selection circuit 17. When processing the binary image data of three lines and three columns shown in FIGS. 4 and 5, the original data of the target pixel is processed by the F / F connected to the output terminal of the one-line delay memory 21 as shown in FIG. F circuit 24
a.

The selection signal Sc from the comparator 38 is input to the selection terminal SEL of the selection circuit 17. Selection circuit 17
In, the input terminals A and B are selected and output according to the level “1” or “0” of the selection terminal SEL. That is, the level of the selection signal Sc input to the selection terminal SEL is “0”.
In the case of BL <th, the original density BL of the surrounding pixels is smaller than the threshold value th, so that it is determined to be a binary character portion or a background portion, and isolated point removal data obtained by removing an isolated point (input to the input terminal A). The output signal from the isolated point removing unit 15 is output from the selection circuit 17. BL ≧ 1 when the level of the selection signal Sc input to the selection terminal SEL is “1”
In the case of th, since the document density BL of the surrounding pixels exceeds the threshold value th, isolated point removal is not performed, and the target pixel data shown in FIG.
Output from

In this embodiment, the target pixel is changed from black to white. That is, although the isolated point is removed, the noise removal of replacing the white of the target pixel with black can be performed by the same signal processing.

[0031]

As described above, the facsimile apparatus according to the first to fifth aspects performs the isolated point removal when the document density calculated from the surrounding pixels of the target pixel is low, and
In the case of a halftone area where the surrounding pixel density is high, the pixel data of interest is output, and thereafter, for example, printing is performed while skipping a white line. It is possible to reduce the printing time due to the removal of the white line and to reduce the printing time, to obtain high-quality printing without noise, and to prevent the deterioration of pseudo halftone printing.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a facsimile apparatus of the present invention.

FIG. 2 is a block diagram illustrating a detailed configuration of an isolated point removing unit illustrated in FIG. 1;

FIG. 3 is a block diagram illustrating a detailed configuration of an image area separation unit illustrated in FIG. 1;

FIG. 4 is a diagram for explaining a target pixel and surrounding pixels in the embodiment.

FIG. 5 is a diagram showing coordinates of a target pixel and surrounding pixels shown in FIG. 4;

FIG. 6 is a block diagram showing an example of a receiving system of a conventional facsimile apparatus.

[Explanation of symbols]

 Reference Signs List 14 Reduction processing operation unit 15 Isolated point removal unit 16 Image area separation unit 17 Selection circuit 21, 31 1-line delay memory 22, 32 2-line delay memory 23a to 35n F / F circuit 28 Isolated point removal logic operation unit 36 Black pixel addition Unit 37 threshold setting unit 38 comparator

Claims (5)

(57) [Claims] An isolated point removing unit that performs a logical operation on an image signal pattern of a peripheral pixel with respect to a target pixel in received facsimile binary data and removes the isolated point when the target pixel is determined to be an isolated point; The first selection signal is output when the document density calculated based on the surrounding pixels of the target pixel is smaller than a preset threshold value and the surrounding pixel density is light, and conversely, when the surrounding pixel density is in a halftone region with a high density. An image area separation / selection unit that outputs a second selection signal to the image data from the isolated point removal unit with the first control signal and outputs the selected image data with the second control signal. A facsimile apparatus comprising: selecting means for selecting and outputting pixel data. 2. An isolated point removing means, comprising: a first plurality of delay circuits for delaying a plurality of line signals of binary image data so as to coincide with a first line signal in the plurality of lines at the same time; A second plurality of delay circuits for adjusting the plurality of pixel column signals of the plurality of lines to the same time as the pixel column signals of the first line; and image signals from the first and second plurality of delay circuits. 2. The facsimile apparatus according to claim 1, further comprising: an isolated point removal logical operation unit that performs a logical operation on the pattern and performs removal of the isolated point when the target pixel is determined to be an isolated point. 3. An image area separation / selection means, comprising: a first plurality of delay circuits for delaying a plurality of line signals of binary image data so as to coincide with a first line signal in the plurality of lines at the same time. A second plurality of delay circuits for adjusting the plurality of pixel column signals of the plurality of lines to the same time as the number of pixel column signals of the first line; and an image from the first and second plurality of delay circuits. From the signal
A black pixel adder for calculating the original density of the surrounding pixels; a threshold setting unit for setting a threshold value for comparison with the original density obtained by the black pixel adder; and an original from the black pixel adder The first selection signal is output when the density is smaller than the threshold value and the surrounding pixel density is light, and the second selection signal is output when the opposite surrounding pixel density is high.
The facsimile apparatus according to claim 1, further comprising: a comparator that outputs a selection signal of: 4. The facsimile apparatus according to claim 3, wherein the density of the document is obtained from the total number of black pixels of surrounding pixels by a black pixel adder. 5. The facsimile apparatus according to claim 2, wherein a flip-flop circuit is used as the delay circuit.