JP2940441B2 - Facsimile machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a facsimile apparatus for converting received image data to a linear density of a predetermined value and printing the converted data.

[0002]

2. Description of the Related Art In general, a facsimile apparatus has three reading modes, i.e., a normal mode, a fine mode, and a super fine mode, for reading a document. In the normal mode, the reading linear density in the sub-scanning direction is 3.85 lines / mm, in the fine mode, twice as high as 7.7 lines / mm, and in the super fine mode, twice as high as 15.
An image on a document is read at a line density of 4 lines / mm.

On the other hand, in a facsimile apparatus, when printing received image data on recording paper, a line density of 7.7 lines / mm corresponding to the fine mode or 15.4 lines / mm corresponding to the super fine mode is used. Some are designed to print. When the linear density of the received image data is lower than the recording linear density, printing of the received image data is performed in a state where the linear density of the received image data is converted to a linear density twice as large as the recording linear density. Like that. For example, when the linear density of the received image data is 3.85 lines / mm corresponding to the normal mode and the recording linear density is 7.7 lines / mm corresponding to the fine mode, as shown in FIG. The line data constituting the received image data is successively repeated twice for each line data, and converted to a line density of twice the line density of the received image data, ie, 7.7 lines / mm, and then printed. I am trying to do it.

In such a facsimile apparatus, when an error occurs in a certain receiving line, a line immediately before the error line is printed again instead of the error line. For example, the linear density of the received image data is 3.85 lines / mm and the recording linear density is 7.
It is assumed to be 7 lines / mm. In this case, if a certain line B is an error line as shown in FIG. 5, the line A immediately before the same line B is replaced by the error line B again.
Printed multiple times. However, in such a process, the same line A is printed four times in succession, and the printed image on the recording paper becomes unsmooth, resulting in an undesirable result such as a decrease in image quality. .

On the other hand, in the facsimile apparatus, when printing received image data, a smoothing process for determining the black and white of each pixel data in the image data in accordance with the black and white of a plurality of pixel data existing around the pixel data. There is something to do. In this smoothing process, for example, three consecutive lines are used, and the black and white of each pixel data of the intermediate line is determined to be more naturally harmonized with the black and white of each pixel data of the lines before and after that line. Processing is performed. Therefore, according to this smoothing process, a smooth and high quality printed image can be obtained.

Therefore, in the case where the above-described error processing is performed, if the error-processed image data is smoothed, the error-processed image data can be smoothed. For example, as shown in FIG. 5, the line density of the received image data is 3.85 lines / mm.
It is assumed that the recording linear density is 7.7 lines / mm and the receiving line B is an error line. In this case, Z, Z,
As shown in A, A, A, A, C, C,..., Line density-converted line data is sequentially input for smoothing processing. For example, when the smoothing process is performed using the three input lines ZZA, the black and white of each pixel data of the intermediate line Z is determined by the lines Z and A
Is determined to be more naturally harmonized with the black and white of each pixel data. Therefore, image data that has become unsmooth due to the above-described error processing can be smoothed by such smoothing processing.

[0007]

However, as shown in FIG. 5, when the error line B is replaced with the line A immediately before the error line B, the three line data used for the smoothing process are AAA. All lines may be the same line, and may be continuous twice. When the smoothing process is continuously performed a plurality of times based on the same three line data, the effect of the smoothing process can hardly be expected, and the portion where the error process is performed is sufficiently smoothed. Therefore, it was not possible to sufficiently prevent the deterioration of the image quality.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to smooth received image data subjected to linear density conversion. Another object of the present invention is to provide a facsimile apparatus which can sufficiently exhibit the effect of the smoothing process and improve the image quality.

[0009]

In order to achieve the above object, a facsimile apparatus according to claim 1 receives a facsimile.
Each line data that composes image data is continuously
Conversion means for converting the linear density to a predetermined density and outputting the same;
A smoothing means for performing a smoothing process on the density-converted image data;
In the facsimile apparatus provided with, the conversion means,
2n (n is a natural number) times the linear density.
If the receiving line is an error line,
Instead of the line, line data before and after the same line is not repeated n times
The linear density conversion is performed by outputting the data.

[0010]

[0011] In the invention described in claim 2 is the facsimile machine of the serial <br/> mounting in claim 1, the smoothing means, the monochrome pixel data in each line data, present around the pixel data Is determined according to the black and white of a plurality of pixel data to be processed.

Accordingly, the first and second aspects of the present invention have the following effects. In the facsimile apparatus according to the first aspect, even if there is an error line, the error line portion is filled with the lines before and after the same line, so that the same line data is significantly more continuous than other line data. I will not do it. Therefore, the effect of the smoothing process can be sufficiently exhibited. The receiving line
If the error line is an error line,
Line density conversion is performed using the same line before and after the line.
Will be

[0013]

[0014] In the facsimile apparatus according to claim 2,
In the smoothing process, the black and white of certain pixel data is determined to be more naturally harmonized with the black and white of a plurality of pixel data existing around the pixel data.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a circuit configuration of a facsimile apparatus according to one embodiment. A CPU (Central Processing Unit) 1 has a ROM (Read Only Memory) storing a program and the like for controlling the operation of the entire apparatus.
2, and a RAM (random access memory) 3 for temporarily storing various information. The NCU (network control unit) 4 has a function of controlling connection with a telephone line, transmitting dial pulses corresponding to the fax number of the other party, and detecting an incoming call. The modem 5 modulates and demodulates transmission and reception data.

The reading section 6 reads an image on a document set on a document table (not shown). The modem buffer 7 temporarily stores transmission / reception data, and transfers image data to the modem 5 when transmitting, and temporarily stores image data transferred from the modem 5 when receiving.

The CPU 1 constitutes an encoding / decoding means for transmitting transmission image data by a modified Huffman system (MH system).
And the like, and transfers it to the modem buffer 7, decodes the received image data transferred from the modem buffer 7 into a black and white run-length, and transfers it to the buffer memory 8 as image data. As shown in FIG. 3, the buffer memory 8 includes, for example, three first to third line memories 8a, 8b, and 8c, and temporarily stores the image data for three lines. A smoothing processing circuit 9 as a smoothing means performs a smoothing process (to be described in detail later) using line data for three lines transferred from the buffer memory 8. The recording unit 10 prints one line at a time on recording paper based on the image data output from the smoothing processing circuit 9. Note that, in the present embodiment, the recording unit 10 is 7.7 lines / mm corresponding to the fine mode.
It is configured to print at a linear density of.

The CPU 1 constitutes a conversion means, converts each line data stored in the buffer memory 8 into a predetermined line density corresponding to the recording line density, and transfers it to the smoothing processing circuit 9. For example, when the line density of the received image data is 3.85 lines / mm corresponding to the normal mode, the CP
U1 outputs each line data in the buffer memory 8 twice for one line data.

Next, the configuration of the smoothing processing circuit 9 will be described. As shown in FIG. 3, the smoothing processing circuit 9
When three lines of line data transferred from the buffer memory 8 are stored in a line buffer (not shown), three pieces of pixel data Pd are extracted from each line data, that is, 3 × 3 pieces of line data from three lines of line data. Of pixel data Pd are extracted in a matrix. And
The pixel data Pd is output to the determination processing circuit 11 in parallel. At this time, the pixel data Pd located at the center of the matrix becomes the target pixel data X. Then, in accordance with the black and white pattern of the eight pieces of pixel data Pd around the target pixel data X, the determination processing circuit 11 determines any of the black and white data to be taken by the target pixel data X.

For example, the data referred to when determining the data to be taken by the target pixel data X is the ROM
2 stores in advance table data (not shown). In this table data, one of black and white pixel data to be taken by the target pixel data X corresponds to each of the black and white patterns of the eight pixel data Pd existing around the target pixel data X at the center of the matrix. Is set.

Therefore, when the nine pixel data Pd extracted in a matrix are input to the determination processing circuit 11,
The determination processing circuit 11 selects one of black and white data corresponding to the black and white pattern of the input pixel data Pd according to the table data. Then, the data is used as the pixel data PdX after the smoothing process,
Output to

As described above, the smoothing processing circuit 9
From the line data for the lines, 3 × 3 pieces of pixel data Pd are sequentially taken out in a matrix and smoothed,
The pixel data PdX after the processing is sequentially output to the recording unit 10.

Next, the operation of the facsimile apparatus configured as described above during the linear density conversion processing of the received image data will be described with reference to the flowchart shown in FIG. still,
In this flowchart, the reading line density of the original on the transmitting side is
That is, the description is made on the assumption that the linear density of the received image data is 3.85 lines / mm corresponding to the normal mode. Although not shown in the flowchart, the information on the linear density of the received image data is notified to the receiving side in advance by exchanging a facsimile procedure signal with the transmitting side before the image data communication.

As shown in FIG. 2, when image data encoded by a predetermined encoding method is transmitted from the transmitting side and the image data is received, the CPU 1 transmits the received image data for one line. The data is decoded into a black and white run length and stored as image data in predetermined line memories 8a to 8c of the buffer memory 8 (steps S1 and S2). Next, the CPU 1 determines whether or not the line data decoded into the image data is an error line (step S3). This decision is made when decoding the encoded data, for example, if the encoded data is encoded in the MH system, whether the encoded data exists in the code defined in the MH system. The determination is made based on whether or not the sum of the run lengths, in other words, the total number of pixel data of one line has reached a prescribed number as a result of decoding the encoded data for one line.

If it is determined in step 3 that the decoded line data is not an error line, the CPU 1 determines whether the immediately preceding decoded line is an error line (step S4). Here, when the immediately preceding decoding line is not an error line, the CPU 1
The line data stored in the buffer memory 8 in step S2 is output twice to the smoothing processing circuit 9 (step S5). In other words, the received image data having a linear density of 3.85 lines / mm is converted into a linear density corresponding to the recording linear density of 7.7 lines / mm. For example, as shown in FIG. 4, one line data Z that is not an error line and the line immediately before that is determined not to be an error line.
Alternatively, A is reduced to two by the linear density conversion.

On the other hand, if the decoded line data is an error line in step 3, the CPU 1 outputs once the decoded line data stored in the buffer memory 8 immediately before the line in place of the error line. (Step S6). For example, as shown in FIG. 4, one line data B determined to be an error line is invalidated,
Instead, the immediately preceding normal line data A is output once more after the previous two outputs, and is made three lines.

On the other hand, if the immediately preceding decoding line is an error line in step 4, the CPU 1
Outputs the line data stored in the buffer memory 8 in step S2 to the smoothing processing circuit 9 three times (step S7). For example, as shown in FIG. 4, the number of normal line data C immediately after the line data B determined to be an error line is reduced to three. That is, one line data C is composed of two lines for line density conversion and one line data A immediately before the line B for the error line B.
There is a total of three, one for filling each book. As a result, in the data after the linear density conversion, the error line B
Is replaced by the line data A immediately before the line B and the line data C immediately after the line B.

After the processing in steps S5, S6 and S7,
The CPU 1 determines whether or not the reception of the image data for one page has been completed (step S8). If the reception has not been completed, the CPU 1 returns to the step S2 and repeats the steps S2 to S2.
Step 8 is repeated. When the reception of the image data of one page is completed, the CPU 1 determines whether or not there is the received image data of the next page (step S9). The process of S9 is repeated, and if there is no data of the next page, all processes are ended.

According to the above processing, the line data subjected to line density conversion such as Z, Z, A, A, A, C, C, C. Are sequentially input for the conversion process. In this case, the three line data used for the smoothing process are AAA or CCC.
May be all the same line, but it does not continue more than once. For this reason, the effect of the smoothing process on the place where the error processing is performed can be enhanced as much as possible. And image quality can be improved.

In addition, in order to achieve the above-mentioned effects, the smoothing processing method having complicated processing is not changed.
Since the line density conversion is simply performed using the lines before and after the error line instead of the error line, the configuration is simple.

Moreover, since the lines before and after the error line are equally used one by one, the portion of the error line can be filled with the best balance, and the deterioration of the image quality can be suppressed as much as possible.

Although not described in the above-mentioned flowchart, the first to third line memories 8 of the buffer memory 8 are not described.
a to 8c are sequentially used for storing the decoded line data. For example, when the decoded line data is stored in the first line memory 8a, the next decoded line data is stored in the second line memory 8b, and the next decoded line data is stored in the third line memory 8c. Then, the next decoded line data is stored again in the first line memory 8a. As described above, the first to third line memories 8a to 8c are used repeatedly in order. However, if the decoded line data is an error line, the next decoded line data is overwritten on the line memories 8a to 8c storing the error line.

In practice, the process of decoding the line data and storing it in the line memories 8a to 8c and the process of outputting the line data in the line memories 8a to 8c to the smoothing processing circuit 11 are performed in parallel. Done. Moreover, the output of the line data to the smoothing processing circuit 11 is such that the decoded line data is stored in two of the three line memories 8a to 8c, and the decoded line data is stored in the remaining line memories. Is started at the time when is started.

For example, in parallel with the decoding line data being stored in the third line memory 8c, the line data in the first line memory 8a is output to the smoothing processing circuit 11 twice. If the line data stored in the third line memory 8c is an error line, the next decoded line data is stored again in the third line memory 8c. The line data immediately before the error line in the second line memory 8b is output to the smoothing processing circuit 11 three times. At this time, before the output of the line data is completed three times, the third line memory 8c
When the storage of the decryption line data for
The next decoded line data is stored in the first line memory 8a whose output to the smoothing processing circuit 11 has already been completed. Further, when the storage of the decoded line data in the first line memory 8a is completed while the line data immediately after the error line in the third line memory 8c is output to the smoothing processing circuit three times, the next decoding is performed. The line data is stored in the second line memory 8b whose output to the smoothing processing circuit 11 has already been completed.

That is, when the buffer memory 8 is composed of two line memories, the line data immediately after the error line is output from one line memory three times more than the normal two times due to the occurrence of the error line. During this operation, the storage of the next decoded line data in the other line memory may be terminated. In such a case, it is necessary to wait for the completion of the output of the line data from one line memory three times before the next line data can be decoded. For this reason, the decoding process is not performed smoothly. Moreover, since the received image data is continuously transmitted, while the decoding of the received line data is interrupted, the storage capacity of the modem buffer 7 is increased by that amount to temporarily store the received line. Need to be done.

However, when the buffer memory 8 is composed of three line memories 8a to 8c as in this embodiment, an error line occurs and it is necessary to output the same line data three times. However, there is no need to interrupt the decoding process for the three outputs. Therefore, the decoding process can be performed smoothly, and there is no need to increase the storage capacity of the modem buffer 7.

The present invention can be embodied with the following modifications. (1) As a method of the smoothing processing, a method different from the above-described embodiment is used. For example, among the three line data used for the smoothing process, the smoothing process is performed such that the run length of the intermediate line data is set to the average value of the run lengths of the preceding and succeeding line data.
Also in this case, a smooth and high-quality image can be obtained as in the case of the first embodiment. Further, the number of line data used for the smoothing process is set to four or more, and the matrix in the smoothing processing circuit 9 of the embodiment is set to 4 × 4 or more. In this way, it is possible to determine the black and white of the predetermined pixel data by adopting the black and white pattern of the surrounding pixel data more widely, and it is possible to make the image smoother and of higher quality.

(2) Similarly, when an error line continues two or more times, the error line portion is similarly filled with the same number of normal line data before and after the error line. (3) As in the embodiment, not only the case where the normal mode is changed to the fine mode, that is, the case where the double linear density conversion is performed, but also the case where the normal mode is changed to the super fine mode,
In other words, the lines before and after the error line are similarly used even when performing the quadruple line density conversion. In addition, the conversion from the fine mode to the super fine mode should be applied as the double linear density conversion.

In this case, the same effect as in the first embodiment can be obtained.

[0040]

Since the present invention is configured as described above, it has the following effects. According to the first aspect of the present invention, in the smoothing processing of the received image data subjected to the linear density conversion, even if there is an error in the receiving line, the effect of the smoothing processing can be sufficiently exhibited. , And the line density using the lines before and after the error line.
When performing the conversion, the front and rear lines are used equally, so that the image quality can be improved.

[0041]

According to the second aspect of the present invention, during the smoothing process, the black and white of a certain pixel data is determined to be more naturally harmonized with the black and white of a plurality of pixel data surrounding the pixel data. Therefore, the image quality can be improved.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram of a facsimile apparatus showing one embodiment.

FIG. 2 is a flowchart showing a linear density conversion process at the time of reception.

FIG. 3 is an explanatory diagram schematically showing a processing operation by a smoothing processing circuit.

FIG. 4 is an explanatory diagram schematically showing a linear density conversion process.

FIG. 5 is an explanatory view schematically showing a conventional linear density conversion process.

[Explanation of symbols]

1. CPU constituting conversion means, 2. ROM, 3. RA
M, 8: buffer memory, 9: smoothing processing circuit as smoothing means, 10: recording unit, 11: determination processing circuit.

Claims (2)

(57) [Claims] 1. A conversion means for continuously converting each line data constituting received image data a predetermined number of times, converting the line data to a predetermined double line density and outputting the same, and a smoothing unit for performing a smoothing process on the line density converted image data. A facsimile apparatus comprising: means for converting the linear density to 2n (n is a natural number) times the linear density;
If the receiving line is an error line
In that case, replace the error line with the lines before and after the line.
Outputting in-data n times enables linear density conversion.
Facsimile machine to do . 2. The image processing apparatus according to claim 1, wherein the smoothing means determines black and white of each pixel data in each line data according to black and white of a plurality of pixel data existing around the pixel data.
The facsimile apparatus according to claim 1 .