JPH0955851A - Facsimile equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce picture data with a desired reduction rate while keeping the entire image of a picture. SOLUTION: A reception means 10 which receives picture data through a telephone network, a reduction means 12 which reduces picture data stored in the reception means 10, a print means 16 which prints out picture data reduced by the reduction means 12, and a paper carrying means 14 which carries cut paper sheet to the print means 16 are provided. Further, a blocking part 20 which divides picture data into plural blocks by several lines based on the total number of lines of this picture data and a line thinning part 22 which eliminates a prescribed number of lines in each of blocks divided by the blocking part 20 are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a facsimile machine, and more particularly to a facsimile machine for printing received image data on cut sheets of A4 size or the like.

[0002]

2. Description of the Related Art In recent years, as a recording paper used for printing a document received by a facsimile machine, there is an increasing demand for cut paper of a fixed size rather than continuous paper from the viewpoint of filing. In addition, in the printing by the laser system, generally, a cut paper of a fixed size is often used rather than a continuous paper.

Image data of a document read by the reading means (scanner section) of the facsimile apparatus on the transmission side is transmitted via the telephone line network. The reading unit reads the document as one line of data in the main scanning direction, and this is sequentially repeated in the sub-scanning direction perpendicular to the main scanning to form image data of the document. The number of pixels in the main scanning direction is specified to be a certain number, but the number of lines in the sub scanning direction varies depending on the length of the document.

Further, since additional information such as a sender is added to a transmission original at the time of transmission, the size in the sub-scanning direction is often longer than the standard size even if the width in the main scanning direction is the standard size. appear.

In the facsimile apparatus on the receiving side, when such a long document is received, in order to record it on a cut sheet of a standard size, some reduction processing is performed or one page is recorded in full size. There is no other.

However, the additional information such as the transmission source is often about several tens of lines, so that it is economical to use one standard size recording paper unless there is a reason that it must be the original size. is not. Therefore, the reduction process is performed, but at that time, the image quality information is lost or the image quality is deteriorated.

Here, as an image reduction method for reducing the loss of image information and the deterioration of image quality, Japanese Patent Laid-Open No. 3-2581 has been proposed.
There is a technology disclosed in No. 67. In this method, the number of black pixels in one line is counted to detect whether the number of black pixels is equal to or less than a certain value, and when the number of lines in which the number of black pixels is less than or equal to a certain value is a certain number of consecutive lines, one line of data is thinned At the same time, from the thinned line to the predetermined number of lines, the size is reduced by not thinning, and is reduced to the standard size length in the sub-scanning direction or less.

However, in this method, the number of thinned lines may become smaller than the desired number of thinned lines, and the reduction processing cannot be effectively performed. Further, the thinning lines are not uniform with respect to the entire image of the image (for example, the line spacing of the document becomes narrow, or the line spacing that should have been uniform varies in the document). ), It will be different from the image of the transmitted image.

[0009]

The first problem of the conventional technique is that the number of lines to be thinned out may not be more than the desired number of thinning lines in the reduction processing. Then, since the reduction ratio does not reach the predetermined reduction ratio, there is an inconvenience that printing is eventually performed using several sheets of paper.

Further, in this conventional example, since the reduction ratio varies depending on the contents of the document, it is preferable that the documents having the same format include many lines having a smaller number of black pixels than the threshold value. , The reduction rate will be high.
Furthermore, even with image data of the same size, the number of black pixels is often large in images such as photographs, the number of thinned lines is small, and the reduction ratio is low, but in documents composed of characters, line spacing etc. Is greatly reduced, and the reduction rate is higher than that of images such as photographs. As described above, there is an inconvenience that the reduction ratio is not stable.

The second problem is that the image is distorted. In many cases, a document composed of characters has a character portion and a line space. In this case, thinning processing is performed in the line space, but each line space in the document data is thinned. Since it is not uniformly determined, the result of reduction processing is an unnatural document in which a certain line spacing is wide and a certain line spacing is narrow. Also, in the case of image data with many white portions, it becomes extremely short.
Then, there is an inconvenience that the overall print result is unbalanced, the document becomes hard to read, and the layout is different from the intention of the sender.

The reason why these first or second problems occur is that the thinning-out candidate line is detected with a certain threshold value.
This is because the thinning-out candidate line is thinned out when a certain number of consecutive lines are continuously formed, and therefore, depending on the content of the image data, the thinning-out candidate line is extremely reduced or hardly reduced depending on the content of the image data.

A third problem is that in order to realize a certain reduction ratio, not only an image memory but also a complicated arithmetic processing circuit is required. The reason is that the number of black pixels is counted in advance for all lines of the image data, and the threshold value, the value of the number of consecutive thinning candidate lines, and the value of the number of unthinned lines after thinning are set. This is because it is necessary to calculate so as to obtain a desired reduction ratio.

[0014]

It is an object of the present invention to reduce the image data at a desired reduction rate while maintaining the overall image of the image with a simple circuit configuration, and to reduce the image information by the reduction processing. It is an object of the present invention to provide a facsimile device capable of reducing loss and deterioration of image quality.

[0015]

Therefore, in the present invention, as a first means, a receiving means for receiving image data through a telephone line network, and a reducing means for reducing the image data accumulated in the receiving means. A printing unit that prints out the image data reduced by the reducing unit and a sheet conveying unit that conveys the cut sheet to the printing unit are provided. Moreover,
The reducing unit thins out the image data into a plurality of blocks every several lines based on the total number of lines of the image data, and thins out a predetermined number of lines for each block divided by the blocking unit. And a line thinning section.

In the first means, a predetermined number of lines are thinned out for each of the blocks divided by the blocking unit, so that a part of the received image data is thinned out to an extremely large amount, or almost not thinned out. The received data is reduced while maintaining good overall balance.

In the second means, in addition to the items specifying the first means, the reduction means calculates the reduction rate of the image data based on the total number of lines of the image data and the size of the cut paper. The calculation unit and the thinning setting unit that determines the number of blocks and the number of thinning lines for each block based on the reduction ratio calculated by the reduction ratio calculation unit are provided.

For this reason, the second means calculates the number of lines required for reduction according to the length of the received data in the sub-scanning direction.

In the third means, in addition to the matters for specifying the second means, the line thinning-out section includes a thinning-out judgment circuit for judging a line from which image data intermediately outputted from the receiving means is thinned out. A first thinning line is determined to be thinned out if the number of black pixels of the block is not more than a predetermined threshold value when the number of thinning lines for each block set by the thinning setting unit is not exceeded. If the number of thinning lines for each block does not reach the number of thinning lines for each block depending on the thinning determination function and the first thinning determination function, the lines are thinned even if the number of black pixels in the one line is equal to or larger than a predetermined threshold value. It has a second thinning-out determination function for determining.

In the fourth means, in addition to the matters for specifying the third means, the line thinning section finishes counting the number of black pixels in one line and the number of black pixels. And a line number counter for counting the number of lines.

In the fifth means, in addition to the matter for specifying the fourth means, a line buffer memory in which the image data output from the receiving means is stored line by line is additionally provided in the printing means, and a line thinning unit is provided. However, a line buffer memory control function is provided for permitting the output from the line buffer memory to the printing unit for the line determined not to be thinned by the first or second thinning determination function.

[0022]

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the schematic arrangement of a facsimile apparatus according to this embodiment. The facsimile apparatus receives the image data via the telephone network, the receiving unit 10, the reducing unit 12 for reducing the image data accumulated in the receiving unit 10, and the image data reduced by the reducing unit 12. A printing unit 16 for outputting and a sheet conveying unit 14 for conveying cut sheets to the printing unit 16 are provided.

Moreover, the reducing means 12 divides the image data into a plurality of blocks every several lines based on the total number of lines of the image data, and each block divided by the blocking unit 20. A line thinning unit 22 for thinning a predetermined number of lines is provided for each.

The blocking unit 20 calculates how many blocks the image data is to be divided into, based on the total number of lines of the image data. For example, if one line is set to be thinned out for one block, it is divided into the same number of blocks as the number of lines to be thinned out.

Since the number of lines in the sub-scanning direction that can be printed on a cut sheet of one page is determined by the configuration of the printing means 14, the blocking unit 20 compares the number of lines of one page with the total number of lines of received image data. Then, the number of blocks is calculated. Taking a simple example for explanation, the blocking unit 20 sets the maximum reduction ratio to a reduction of 3/4, and if the number of lines on one page is 75, if the image data is 100 or less, Block it, and if it exceeds it, do not block it.

If the number of lines of the image data is 100, the blocking unit 20 sets 4 lines as one block and thins out one line for each block. Then, the line thinning unit 22 makes 100 lines 7
It is reduced to five. Blocking unit 20 has 76 or more 9
When the number of lines is 9 or less, the number of blocks in 4 lines and the number of blocks in 5 lines are changed appropriately. The calculation of the number of blocks may be performed by the thinning-out setting unit 26 described later.

The line thinning unit 22 reduces the image data by thinning out a predetermined number of lines for each block divided into blocks by the blocking unit 20. For example, when thinning out one line for each block, the final line of each block may be thinned out, or the number of black pixels in one line may be calculated and the line with the smallest number of black pixels may be thinned out. You may do it.

As described above, the blocking unit 20 and the line thinning unit 22 thin a portion in the sub-scanning direction at a uniform interval without extremely thinning it.
A well-balanced document can be printed.

When the facsimile machine selects and prints a plurality of cut sheets, for example, A4 size and B4 size cut sheets, thinning processing is performed according to the sheet size. In this example, the reducing means 12
Reduction ratio calculation unit 24 that calculates the reduction ratio of the image data based on the total number of lines of the image data and the size of the cut sheet.
And a thinning setting unit 26 that determines the number of blocks and the number of thinning lines for each block based on the reduction ratio calculated by the reduction ratio calculating unit 24.

In this example, the blocking unit 20 and the line thinning unit 22 divide the image data into blocks based on the setting by the thinning setting unit 26, and delete the number of lines set for each block. Therefore, uniform reduction can be performed as a whole.

FIG. 2 is a block diagram showing the detailed arrangement of the line thinning section 22.

The line thinning section 22 counts the number of black pixels for each scanning line of image data, and the number of lines counter for counting the number of lines counted by the black pixel number counter 22A. Two
2B, a thinning-out determination circuit 22C that determines whether or not to thin a line based on the number of black pixels and the number of thinned-out lines in a block, and the number of black pixels in one line is counted until the determination of thinning is completed. It has a line buffer memory 22D for accumulating the image data of the one line and transferring the data of the one line to the printing unit in the case of the determination result that the thinning is not performed.

The thinning-out determination circuit 22C includes a thinning-out setting unit 2
A first thinning-out judgment function for judging that the thinning-out line is thinned out when the number of black pixels in the block is less than or equal to a predetermined threshold value when the number of thinning-out lines for each block set by 6 is not exceeded. If the number of thinning lines for each block set by the thinning setting unit 26 does not reach the number of thinning lines for each block depending on the first thinning determination function, the number of black pixels in one line is equal to or greater than a predetermined threshold value. Even if it is determined that the line is thinned, the second
It has a thinning decision function.

The black pixel counter 22A counts the number of black pixels contained in one line of original image data. If the number of black pixels in the nth line is Bn, the black pixel number counter 22
The output value on the nth line of A is Bn. The black pixel number Bn output from the black pixel number counter 22A is input to the thinning determination circuit 22C.

The thinning-out determination circuit 22C determines line thinning-out with a predetermined number of blocks k as one unit according to a desired reduction rate. Here, the number of blocks k is the number of lines that relate the reduction ratio and the frequency of thinning, and the relationship with the reduction ratio is given by the expression that one line among k lines is thinned. For example, when k = 4, 4
Since one line is thinned out, a reduction of 75% can be realized.

The reduction ratio is determined by performing thinning of one line out of four lines and one line out of five by combining the number of blocks, for example, the case of k = 4 and the case of k = 5. As a result, it is possible to realize a reduction ratio of about 78% by thinning out two lines out of nine lines.

In the thinning decision circuit 22C, the value of the black pixel number Bn inputted from the black pixel number counter 22A is compared with the threshold value Th of the black pixel number. If the value of Bn is smaller than Th, this The thinning candidates are n lines. further,
If the thinning candidate is the first one among the k consecutive lines indicated by the number of blocks k, the nth line is determined as the thinning line.

On the other hand, if thinning candidates have already occurred in the same block and it has already been determined that they are thinning lines, this nth line is not a thinning line. If no line that is a thinning-out candidate occurs in the same block, the final line of the block is determined as a thinning-out line. The result determined by the thinning-out determination circuit 22C in this manner controls whether or not image data can be transferred from the line buffer memory 22D, and only the lines determined not to be thinned out are transferred from the line buffer memory 22D.

FIG. 3 shows an example of the image processing result of the reduction processing method of the present invention. The original image is composed of a total of 12 lines of data from the nth line to the (n + 11) th line, and the lines thinned out by the reduction processing of the present invention are the three lines indicated by shaded lines 31, 32 and 33 in the figure. Is. In FIG. 3, in order to make the explanation of the operation easy to understand, a case where 75% reduction, that is, four continuous lines are set as one block and one line is thinned out of the four lines is shown as an example.

In the first block of FIG. 3 (from the nth line to the (n + 3) th line), the number of black pixels in each line is counted, and the number of black pixels in the nth line is larger than the threshold value, and the n + 1th line. Then, it is assumed that the number of black pixels is below the threshold value for the first time in this block. In this case, the n + 1th line (reference numeral 31) is thinned out.

Even if the number of black pixels on the (n + 2) th line and the (n + 3) th line after that is equal to or smaller than the threshold value, thinning is not performed in this block because it has already been thinned out. For the second block (from the (n + 4) th line to the (n + 7) th line) in FIG. 3, the number of black pixels in the line is counted, and the number of black pixels in the (n + 4) th line, that is, the first line in this block is the threshold value. It shall be less than or equal to the value. In this case as well, since it is the first candidate line for thinning out in the block, the n + 4th line (reference numeral 32) is thinned out, and the subsequent n + 5th line, the n + 6th line and the n + 7th line are not thinned out.

Further, the third block (nth + th) in FIG.
(8th line to n + 11th line) indicates processing when the number of black pixels in each line is larger than the threshold value. Since none of the lines are candidates for thinning, the n + 11th line (reference numeral 3), which is the final line of this block.
Thin out 3).

In this way, by thinning out three lines out of the 12 lines shown in FIG. 3, the desired reduction ratio of 75% can be achieved.

Next, the operation sequence of the reduction processing according to the present embodiment will be described with reference to the flow chart with reference to FIG.

In FIG. 4, reference numeral N indicates the number of continuous lines included in one block, and reference numeral n indicates the nth line in one block. The symbol j indicates whether or not thinning has been performed within the block. A flag indicating that thinning has not been performed when j = 0 and a flag indicating that thinning has already been performed when j = 1. is there.
Further, Bn represents the number of black pixels in the n-th line in the block, and Th represents the threshold value for detecting the thinning-out candidate line. Here, one line is thinned out for one block.

First, as shown in FIG. 4, step S
In 1, the initial state is n = 1, j = 0, that is, the first line in the block, and the state is reset to the state where thinning is not performed yet.

Next, in step S2, the image data of one line is read. Further, in step S3, the number of black pixels is counted by the black pixel number counter 22A, and the resulting number of black pixels in the nth line is set to Bn, and the process proceeds to step S4.

In step S4, it is determined whether thinning has already been performed in the block. If j = 1, that is, if buzzing has already been performed, step S7
Move to. On the other hand, if j = 0, the process proceeds to step S5.

In step S5, it is determined whether the line is the last line in the block. If the n-th line in the block being processed is the final line of the block (n = N), the process proceeds to step S8. On the other hand, if it is not the final line of the block, the process proceeds to step S6.

In step S6, the number Bn of black pixels in the nth line is compared with the threshold Th to determine whether the nth line is a thinning candidate line. If the number of black pixels Bn is less than or equal to the threshold Th, the line is a thinning candidate line, and the process proceeds to step S8. On the other hand, the number of black pixels Bn is the threshold value T
If it is larger than h, it is not a thinning-out candidate line, and the process proceeds to step S7.

In step S7, the n-th line is determined not to be thinned out, so the data is transferred from the line buffer memory 22D as valid data, and the process proceeds to step S10.

In step S8, the thinning candidate line is determined by the judgments in steps S5 and S6, so the thinning out of the nth line is not performed, and the process proceeds to step S9.

In step S9, the flag j indicating that thinning has been performed in the block is set to j = 1, and the process proceeds to step S10.

In step S10, it is determined whether the processing has been completed for all the lines of the image data. If the processing is completed for all lines, the processing according to the flow of FIG. 4 is completed.

If there is an unprocessed line (step S10)
(No in step S11), the process proceeds to step S11.

In step S11, it is determined whether the processing is completed for all the lines in the block.
If the processing has been completed for all the lines in the block, the processing returns to step S1 to perform the processing of the next block, and the above-described flow is repeated. When there is an unprocessed line in the block (when N = 0), the process proceeds to step S12.

In step S12, the line number counter 2
2B counts up the value of n by 1, and the step S2
Move the process to Further, the processing is performed on the next line.

As described above, according to the processing shown in FIG. 4, the frequency of thinning lines is made equal to the desired reduction ratio by setting the number of lines in one block so that there is one line in one block. Therefore, it is possible to perform the reduction process at the minimum required reduction ratio. Further, since lines are thinned out for each block, lines that are candidates for thinning are detected by the number of black pixels, and the amount of information is small. Since the lines are thinned out, it is possible to reduce loss of image information and deterioration of image quality due to reduction processing. Moreover,
Such reduction processing can be realized with a simple circuit.

In the above description, the block configuration and the operation flow are illustrated.
The distribution of merging or separation of each function, the rearrangement of steps, the order of parallel processing, and the like are arbitrary as long as the functions described above are satisfied, and the above description does not limit the present invention.

Next, a modified example will be described. In the configuration shown in FIG. 1 or FIG. 2, it is also possible to replace the black pixel number counter 22A with a white pixel counter. In this case, the amount of information is small because the number of white pixels is large.
The thinning decision circuit 22C may determine a thinning-out candidate line by comparing the number of white pixels with a threshold value if the number of white pixels in the line is larger than the threshold value. Since the total number of pixels in one line is uniquely defined by the image data, it does not differ depending on whether the number of black pixels or the number of white pixels is counted.

As another modification, the number of blocks set as a desired reduction rate in the thinning-out determination circuit 22C can be realized by using a combination of block numbers. For example, it is equivalent to thinning 2 lines out of 15 lines by combining a block having 7 lines and a block having 8 lines and alternately using these two types of blocks.
It is also possible to perform reduction processing with a reduction rate of about 87%.

Regarding the threshold value of the number of black pixels when determining the thinning-out candidate line, the value may be changed depending on the contents of the image data, or the information of the number of black pixels counted by the black pixel counter may be used. May be used as a variable threshold value for tracking the number of black pixels.

Further, in the configuration shown in FIG. 1, the black pixel number counter 22A and the line buffer memory 22 are provided.
D may be for multiple lines. A line buffer memory for a plurality of lines may be used to thin out a thinning candidate line having the smallest number of black pixels among a plurality of thinning candidate lines when determining a thinning-out line.
This is particularly effective when the above threshold value is variable.

The present invention relates to the reduction processing in the sub-scanning direction, but by using it in combination with the reduction processing method in the main scanning direction,
It is also possible to perform a reduction process from a standard size to a standard size (reduction of the same vertical / horizontal reduction ratio) or a reduction process from a long document having a judgment width to a standard size (reduction of different vertical / horizontal reduction ratio).

Further, as shown in FIG. 4, in addition to the items shown in FIGS. 1 and 2, there are a total line number counter 41 for counting the total number of lines of one page and a means for accumulating image data. By adding the image memory 42 and the reduction rate calculation unit 43 that is a means for calculating the reduction rate (thinning pattern) so that the image data has a standard size, it is possible to always reduce the size to a standard size. it can.

The image memory 42 stores the image to be transmitted or the image to be printed. Total line counter 41
Counts the total number of lines for each page of the image stored in the image memory. In the example shown in FIG. 4, although the total number of lines is counted when being accumulated in the image memory 42, the image accumulated in the image memory 42 may be read and the total number of lines may be counted. . Let X be the total number of lines counted by the total line number counter. In the reduction rate calculation portion 43, the total number of lines of a desired standard size is set to Y.
Then, the reduction ratio Z is given by the following equation (1).

Z = Y / X ... Equation (1)

If the combination of the number of thinning blocks for performing thinning determination is determined from the calculated reduction ratio Z and the reduction process shown in the above-described embodiment is performed, the reduction process that always has the standard size can be performed. It will be possible.

[0069]

Since the present invention is constructed and functions as described above, according to this, the line thinning unit thins out a predetermined number of lines for each block divided by the blocking unit, so that the received image data is received. It is possible to reduce the received data while keeping a good overall balance by preventing a portion of the image from being thinned out to an extremely large extent or being not thinned out almost without thinning it out. The image data can be reduced at a desired reduction ratio while maintaining a good image. Therefore, even if the size of the cut sheet such as A4 size is slightly exceeded, one sheet is sufficient. It is possible to reduce and print out at a reduction ratio, and since it is made into blocks and thinned out for each block, it is possible to reduce loss of image information and deterioration of image quality due to reduction processing. It is possible to provide a superior facsimile unprecedented that can.

[Brief description of drawings]

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

FIG. 2 is a block diagram showing a detailed configuration of a line thinning unit shown in FIG.

FIG. 3 is an explanatory diagram showing an example of image data thinning processing by a line thinning unit shown in FIG.

FIG. 4 is a flowchart showing an operation sequence of thinning processing by the configuration shown in FIGS. 1 and 2.

FIG. 5 is a block diagram showing another detailed configuration of the reducing means shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Receiving means 12 Reduction means 14 Paper conveying means 16 Printing means 20 Blocking section 22 Line thinning section 24 Reduction rate calculating section 26 Thinning setting section

Claims (5)

[Claims] 1. A receiving means for receiving image data via a telephone line network, a reducing means for reducing the image data accumulated in the receiving means, and a print for printing out the image data reduced by the reducing means. In a facsimile apparatus including a unit and a sheet conveying unit that conveys a cut sheet to the printing unit, the reducing unit divides the image data into a plurality of blocks every several lines based on the total number of lines of the image data. A facsimile apparatus comprising: a block dividing unit for dividing and a line thinning unit for thinning a predetermined number of lines for each block divided by the block forming unit. 2. The reduction means calculates a reduction rate of the image data based on the total number of lines of the image data and the size of the cut sheet, and a reduction rate calculation section. 2. The facsimile apparatus according to claim 1, further comprising a thinning setting unit that determines the number of blocks and the number of thinning lines for each block based on the reduction ratio. 3. The line thinning-out unit includes a thinning-out determination circuit that determines a thinning-out line in the image data output from the receiving unit, and the thinning-out determination circuit is for each block set by the thinning-out setting unit. And a first thinning-out determination function that determines thinning out the line when the number of black pixels in the line is less than or equal to a predetermined threshold value when the number of thinning lines for each block is not exceeded. Depending on the determination function, if the number of thinning lines for each block does not reach the number of thinning lines, a second thinning determination function that determines that the line is thinned even if the number of black pixels in one line is equal to or greater than a predetermined threshold value. The facsimile apparatus according to claim 2, further comprising: 4. The line thinning unit includes a black pixel number counter that counts the number of black pixels in one line, and a line number counter that counts the number of lines for which the number of black pixels has been counted. The facsimile apparatus according to claim 3, which is characterized in that. 5. A line buffer memory, in which the image data output from the receiving unit is stored for each line, is additionally provided to the printing unit, and the line thinning unit has the first or second thinning determination function. 5. The facsimile apparatus according to claim 4, further comprising a line buffer memory control function for permitting output from the line buffer memory to the printing unit for a line determined not to be thinned out.