JPH07177359A - Facsimile equipment - Google Patents

Abstract

PURPOSE:To obtain a facsimile equipment capable of efficiently transmitting image information by providing the equipment with respectively specific image reader, image processing means, encoding/decoding means, and control means. CONSTITUTION:A scanner 4 reads out an image of an original by decomposing picture elements by specific transmission resolution (SSF) indivisual to its equipment sort and outputs binarized image data obtained by binarizing respective picture elements. An image processing part 7 is provided with a processing function for executing linear density conversion from the image data of the SSF to image data of optional transmission resolution (DTL) and a processing function for executing linear density conversion from the image data of the SSF to image data of standard transmission resolution (STD). In the case of transmitting an image of an original, image data read out by the scanner 4 is encoded by an encoding/decoding part 8, and after temporarily storing image data in a image storage device 9 as an image data state, a specified destination is called and the image information stored in the device 9 is transmitted to a destination terminal. Since reading resolution corresponding to the contents of the original image is set up, an image with fine image quality and high transmission efficiency can be transmitted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a facsimile apparatus capable of transmitting image information having an appropriate transmission resolution.

[0002]

2. Description of the Related Art Generally, in a facsimile machine, as a reading resolution of a document image, a standard resolution and a (standard) resolution are used.
In addition to the optional fine resolution, it has a higher resolution for reading.

Usually, when a document image is read at a higher resolution, the image quality of the transmitted image is further improved. Therefore, it is advantageous from the viewpoint of the image quality of the transmitted image to read the document with a resolution as high as possible. When the original image is read at a higher resolution, the amount of data increases, and the communication cost for image transmission increases.

For this reason, in many conventional facsimile apparatuses, the reading resolution of the original image can be set by the user's setting. As a result, in the case of a document including a fine image, the user can set a higher reading resolution, which enables efficient image transmission according to the content of the document image.

[0005]

However, such a conventional device has the following disadvantages.

That is, since the user sets the reading resolution according to the content of the transmitted document, the user's trouble is complicated. Further, if the user's setting is not appropriate, the image obtained on the receiving side may be unclear, or the amount of transmission data may be carelessly increased to increase the communication cost.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a facsimile apparatus capable of efficiently transmitting image information.

[0008]

SUMMARY OF THE INVENTION The present invention is directed to an image reading device capable of binary reading an original image at the highest resolution among predetermined transmission resolutions, and binarized image data obtained by reading the image reading device. With image processing means for converting the transmission resolution to a lower resolution, and converting the binarized image data into image information coded and compressed by a predetermined encoding method, and further converting the image information into the original binarized image data. Encoding / decoding means for decoding the image into a single image, and an image obtained by encoding / compressing the binary image data obtained by reading one page of the original image by the image reading device by the encoding / decoding means. When the data amount of information is smaller than the predetermined value, the binarized image data is converted into low resolution binarized image data having a lower resolution transmission resolution by the image processing means, and the low resolution binarized image is converted. De The data are those having a control unit for use as a transmission image information the image information obtained by compression coding by the coding and decoding means.

Further, an image reading device capable of binary reading an original image at the highest resolution of a predetermined transmission resolution, and binary image data obtained by reading the image reading device are transmitted at a lower resolution. And image processing means for converting the binarized image data into image information coded and compressed by a predetermined encoding method, and encoding / decoding for decoding the image information into the original binary image data. Means and the binary image data obtained by reading one page of the original image by the image reading device is encoded and compressed by the encoding / decoding means, and the data amount of image information obtained by The image is detected in block units formed by dividing the image in the sub-scanning direction of the image reading device, and the maximum amount of detected data is
When it is smaller than the predetermined value, one page of the binarized image data of the page is converted into the low resolution binarized image data of the lower resolution transmission resolution by the image processing means, and the low resolution binarized The control means uses image information obtained by encoding and compressing the encoded image data by the encoding / decoding means as transmission image information.

Further, an image reading apparatus capable of reading an original image in multi-gradation at the highest resolution among predetermined transmission resolutions, and multi-gradation image data output from the image reading apparatus is subjected to predetermined pseudo-halftone reproduction. Pseudo halftone binarization processing means for binarizing, fixed threshold binarization means for binarizing multi-tone image data output from the image reading device with a predetermined fixed threshold, and the image reading device The image area separating means for determining the multi-tone image data output from the pixel area into the halftone area and the non-halftone area on a pixel-by-pixel basis, and the pixels determined by the image area separating means as the halftone area are the pseudo-intermediate areas. While selecting the halftone binarized data output from the tone binarization processing means, the pixels which the image area separation means determines to be a non-halftone area are output from the fixed threshold binarization means. Select non-halftone binarized data The image synthesizing means, the image processing means for converting the binarized image data output from the image synthesizing means into a transmission resolution having a lower resolution, and the binarized image data output from the image synthesizing means are predetermined. Encoding / decoding means for converting the image information into the image information that has been encoded and compressed by the encoding method and for decoding the image information into the original binary image data,
Data of image information obtained when the binarized image data output from the image synthesizing unit when the image reading apparatus reads one page of the original image is encoded and compressed by the encoding / decoding unit. When the amount is smaller than the predetermined value, the binarized image data is converted into low resolution binarized image data having a lower transmission resolution by the image processing means, and the low resolution binarized image data is It is provided with control means for using image information obtained by encoding and compression by the encoding / decoding means as transmission image information.

Further, an image reading device capable of reading an original image in multi-gradation at the highest resolution among predetermined transmission resolutions, and multi-gradation image data output from the image reading device is subjected to predetermined pseudo-halftone reproduction. Pseudo halftone binarization processing means for binarizing, fixed threshold binarization means for binarizing multi-tone image data output from the image reading device with a predetermined fixed threshold, and the image reading device The image area separating means for determining the multi-tone image data output from the pixel area into the halftone area and the non-halftone area on a pixel-by-pixel basis, and the pixels determined by the image area separating means as the halftone area are the pseudo-intermediate areas. While selecting the halftone binarized data output from the tone binarization processing means, the pixels which the image area separation means determines to be a non-halftone area are output from the fixed threshold binarization means. Select non-halftone binarized data The image synthesizing means, the image processing means for converting the binarized image data output from the image synthesizing means into a transmission resolution having a lower resolution, and the binarized image data output from the image synthesizing means are predetermined. Encoding / decoding means for converting the image information into the image information that has been encoded and compressed by the encoding method and for decoding the image information into the original binary image data,
Data of image information obtained when the binarized image data output from the image synthesizing unit when the image reading apparatus reads one page of the original image is encoded and compressed by the encoding / decoding unit. The amount of data is detected in block units formed by dividing the original image in the sub-scanning direction of the image reading device, and when the maximum amount of detected data is smaller than a predetermined value, one page of the page is detected. Minutes of the binarized image data is converted into low resolution binarized image data of a lower resolution by the image processing means, and the low resolution binarized image data is encoded by the encoding / decoding means. The control means uses the image information obtained by the compression and compression as the transmission image information.

Further, an image reading apparatus capable of reading an original image in multi-gradation at the highest resolution among predetermined transmission resolutions, and multi-gradation image data output from this image reading apparatus are subjected to predetermined pseudo-halftone reproduction. Pseudo halftone binarization processing means for binarizing, fixed threshold binarization means for binarizing multi-tone image data output from the image reading device with a predetermined fixed threshold, and the image reading device The image area separating means for determining the multi-tone image data output from the pixel area into the halftone area and the non-halftone area on a pixel-by-pixel basis, and the pixels determined by the image area separating means as the halftone area are the pseudo-intermediate areas. While selecting the halftone binarized data output from the tone binarization processing means, the pixels which the image area separation means determines to be a non-halftone area are output from the fixed threshold binarization means. Select non-halftone binarized data The image synthesizing means, the image processing means for converting the binarized image data output from the image synthesizing means into a transmission resolution having a lower resolution, and the binarized image data output from the image synthesizing means are predetermined. Encoding / decoding means for converting the image information into the image information that has been encoded and compressed by the encoding method and for decoding the image information into the original binary image data,
Data of image information obtained when the binarized image data output from the image synthesizing unit when the image reading apparatus reads one page of the original image is encoded and compressed by the encoding / decoding unit. When the data amount of the lines excluding the line including the pixel determined to be the halftone region by the image area separating unit is smaller than a predetermined value, the binarized image data is processed by the image processing unit. Control using image information obtained by converting the low-resolution binary image data having a lower resolution to the low-resolution binary image data and encoding and compressing the low-resolution binary image data by the encoding / decoding means as transmission image information. It is equipped with means.

Further, an image reading device capable of reading an original image in multi-gradation at the highest resolution among predetermined transmission resolutions, and multi-gradation image data output from the image reading device is transmitted in a predetermined pseudo halftone. Pseudo halftone binarization processing means for binarizing, fixed threshold binarization means for binarizing multi-tone image data output from the image reading device with a predetermined fixed threshold, and the image reading device The image area separating means for determining the multi-tone image data output from the pixel area into the halftone area and the non-halftone area on a pixel-by-pixel basis, and the pixels determined by the image area separating means as the halftone area are the pseudo-intermediate areas. While selecting the halftone binarized data output from the tone binarization processing means, the pixels which the image area separation means determines to be a non-halftone area are output from the fixed threshold binarization means. Select non-halftone binarized data The image synthesizing means, the image processing means for converting the binarized image data output from the image synthesizing means into a transmission resolution having a lower resolution, and the binarized image data output from the image synthesizing means are predetermined. Encoding / decoding means for converting the image information into the image information that has been encoded and compressed by the encoding method and for decoding the image information into the original binary image data,
Data of image information obtained when the binarized image data output from the image synthesizing unit when the image reading apparatus reads one page of the original image is encoded and compressed by the encoding / decoding unit. A block unit obtained by dividing the data amount of the lines excluding the line including the pixel determined to be the halftone region by the image area separating unit in the sub-scanning direction of the image reading device of the original image. Detected in
When the maximum amount of detected data is smaller than a predetermined value, the binarized image data for one page of the page is converted by the image processing means into a low resolution binary of a transmission resolution of a lower resolution. Converted into image data,
The low resolution binarized image data is provided with a control means for using image information obtained by encoding and compressing by the encoding / decoding means as transmission image information.

[0014]

Therefore, when the code data amount of the image information after the encoding and compression is large, it is determined that the content of the image of the page is fine, and the image data of the maximum reading resolution is transmitted as the transmission image data. If the amount of encoded data is small, it is determined that the content of the image on the page is not very detailed, converted to lower resolution image data, and the converted image data is encoded and compressed. Since the image information formed by transmitting the image is transmitted, the reading resolution is set according to the content of the original image, and as a result, the image quality is good,
Also, image transmission with good transmission efficiency becomes possible. Also,
If an image reading device that distinguishes a halftone area and outputs the binarized image data that has undergone pseudo-halftone binarization processing is provided in that halftone area, the code data amount of the portion excluding the halftone area Since the above determination process is performed based on the above, the appropriate reading resolution can be set in this case as well.

[0015]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 shows a group 3 facsimile apparatus according to an embodiment of the present invention.

In FIG. 1, the system control unit 1 performs control processing of each unit of the facsimile apparatus and facsimile transmission control procedure processing, and the system memory 2 is a control processing program executed by the system control unit 1. , And various data necessary for executing the processing program, and constitutes a work area of the system control unit 1. The parameter memory 3 stores various information unique to the group 3 facsimile machine. Is for storing.

The scanner 4 is for reading a document image at a predetermined resolution, the plotter 5 is for recording and outputting an image at a predetermined resolution, and the operation display unit 6 is a facsimile device. For operation,
It consists of various operation keys and various indicators.

The image processing unit 7 performs a predetermined linear density conversion process for converting the linear density (resolution) of the image data, and the coding / decoding unit 8 processes the image signal by a predetermined coding method (for example, , MH system and MR system) and decodes the coded image information into the original image signal. The image storage device 9 is in the coded and compressed state. This is for storing a lot of image information.

The group 3 facsimile modem 10 is for realizing the modem function of the group 3 facsimile, and is a low speed modem function (V.21 modem) for exchanging transmission procedure signals and mainly exchanging image information. High-speed modem function (V.33 modem,
V. 29 modem, V.29. 27ter modem etc.).

The network control device 11 is used to connect the facsimile device to a public telephone line network and has an automatic call originating / receiving function.

These system control unit 1, system memory 2, parameter memory 3, scanner 4, plotter 5, operation display unit 6, image processing unit 7, encoding / decoding unit 8,
Image storage device 9, group 3 facsimile modem 10,
Also, the network control device 11 is connected to the system bus 12, and data is exchanged between these respective elements.
This is mainly done via the system bus 12.

Data is exchanged directly between the network control device 11 and the group 3 facsimile modem 10.

In the group 3 facsimile apparatus, the transmission resolution of the original image is as shown in FIG.
Any of the transmission resolutions corresponding to the three types of pixels shown in (b) and (c) is selectively used.

The pixel shown in FIG. 3A is CCITT recommendation T.264 which is a recommendation of the function of the group 3 facsimile apparatus.
4 is a pixel having a standard transmission resolution (STD) in No. 4, which has a resolution of 8 dots / mm in the main scanning direction and a resolution (linear density) of 3.85 lines / mm in the sub-scanning direction. With.

The pixel shown in FIG. 3B is CCITT recommended T.264. Optional transmission resolution (DTL) in 4
This pixel has a resolution of 8 dots / mm in the main scanning direction and a resolution (linear density) of 7.7 lines / mm in the sub-scanning direction.

The pixel shown in FIG. 3C is CCITT recommended T.264. Model-specific transmission resolution not included in 4 (SS
F) pixels, whose transmission resolution is 8 in the main scanning direction.
Dot / mm resolution and 14.5 in sub-scanning direction
It has a line / mm resolution (linear density).

The scanner 4 decomposes the original image into pixels at the SSF resolution and reads the original image, and outputs binarized image data in which each pixel is binarized. Further, in this embodiment,
The image processing unit 7 uses the DTL to convert the image data of SSF resolution.
It has a processing function of converting the linear density into image data of the resolution of, and a processing function of converting the image data of the resolution of SSF into the image data of the resolution of STD.

With the above configuration, in the present embodiment, when transmitting a document image, the image data read by the scanner 4 is coded and compressed by the coding / decoding unit 8 and the image is temporarily stored in the state of image information. After storing in the device 9, the memory transmission function of calling the designated destination and transmitting the image information stored in the image storage device 9 to the destination terminal is applied.

Further, the transmission manuscript for one page is scanned by the scanner 4
FIG. 3 shows an example of the processing from the reading in step 1 to the saving in the image storage device 9.

First, with the scanning linear density of the scatter 74 set to SSF (process 101), the scanner 4 is made to read and input one page of the original image, and at this time, the scanner 4 is read.
The image data output from the device is stored in a predetermined image buffer area formed in the system memory 2 (process 10).
2).

Next, the image data for one page stored in the image buffer area is encoded and compressed by the encoding / decoding unit 8 by a predetermined encoding method, and the image information for one page obtained by this is compressed by the system. The image is stored in a predetermined image information buffer area formed in the memory 2 (process 103).

Then, the code data amount CD of the image information for one page stored in the image information buffer area at this time is input (process 104), and this code data amount CD is a predetermined value T1.
It is checked whether or not it is above (decision 105).

If the result of determination 105 is YES, it means that the image of this page is complicated and that there are many fine images. Therefore, with the transmission line density of the image of this page set to SSF (process 106), this process is performed. To finish. As a result, in the subsequent processing, the image of this page has the transmission line density handled as SSF, is temporarily stored in the image storage device 9, and is then transmitted to the designated destination.

When the result of judgment 105 is NO, it is checked whether the code data amount CD is larger than a predetermined value T2 (<T1) (decision 107). When the result of determination 107 is YES, the image of this page is relatively complicated and includes a fine image to some extent. Therefore, the transmission line density of the image of this page is set to DTL (process 108).

Next, the image information for one page stored in the image information buffer area is decoded into the original image data by the encoding / decoding unit 8 and the image data is stored in the image buffer area (process 109). ), 1 of the image buffer area
The image processing unit 7 performs linear density conversion of the image data having the linear density of SSF for the page into the image data having the linear density of DTL (processing 110), and the DTL image data after the linear density conversion is stored in the system memory 2. Save to another image buffer area that you set.

Then, the image data having the linear density DTL stored in the other image buffer area is encoded / decoded by the encoding / decoding unit 8.
The image information obtained by the encoding and compression is stored in the image storage device 9 (process 111). Further, the image information on this page is handled with the transmission line density set to DTL.

When the result of determination 107 is NO, it means that the image of this page does not have a complicated portion and does not include a very fine image. Therefore, the transmission line density of the image of this page is set to STD ( Process 112).

Next, the image information for one page stored in the image information buffer area is decoded into the original image data by the encoding / decoding unit 8 and the image data is stored in the image buffer area (process 113). ), 1 of the image buffer area
The image processing unit 7 performs linear density conversion of the image data having the linear density of SSF for the page to the image data having the linear density of STD (processing 114), and stores the image data of STD after the linear density conversion in the system memory 2. Save to another image buffer area that you set.

Then, the image data having the linear density STD stored in the other image buffer area is encoded / decoded by the encoding / decoding unit 8.
The image information obtained by the encoding and compression is stored in the image storage device 9 (process 115). Further, the image information on this page is handled with the transmission line density set to STD.

In this way, in this embodiment, the complexity of the content of the original image of the page is determined based on the data amount of the image information obtained by encoding and compressing the image data for one page. According to the determination result, the transmission line density of the original image of the page is set. Here, when the content of the document image is more complicated, the data amount of the image information is larger, and therefore the content of the document image can be determined to some extent based on the data amount of the image information. An appropriate transmission line density can be set by the method of setting the transmission line density of the original image according to the present embodiment.

However, for example, in the case of a manuscript image in which fine images are partially concentrated and the images other than that part are all white, the data amount of image information may not be so large. In such a case, it may not be possible to set an appropriate transmission line density by the method for setting the transmission line density of the document image of the above-described embodiment.

In order to cope with such a case itself, for example, as shown in FIG. 4, when the original image is divided into four blocks in the sub-scanning direction and the original image is encoded and compressed, If the data amount of the image information in each block obtained is selected to be the most data amount and the transmission line density of the original image is judged based on the maximum data amount, it is possible to obtain a finer detail. Even when an image is included, the transmission line density can be set to an appropriate value.

FIG. 4 and FIG. 5 show an example of processing in this case from reading the transmission original for one page by the scanner 4 to saving it in the image storage device 9.

First, with the scanning linear density of the scan line 74 set to SSF (process 201), the scanner 4 is made to read and input one page of the original image, and at this time, the scanner 4 is read.
The image data output from is stored in a predetermined image buffer area formed in the system memory 2 (process 20).
2).

Next, after initializing the variable i to 0 (process 203), the value of the variable i is incremented by 1 (process 20).
4), of the image data stored in the image buffer area, the image data of the portion corresponding to the i-th block is encoded and compressed by the encoding / decoding unit 8, and the image information obtained thereby is obtained at that time. It is stored in the address of the image information buffer area corresponding to the block (process 205).

Then, the total amount of data CDT stored in the image information buffer area at that time is input (process 20).
6), the data amount CD (i) of the i-th block is calculated (process 207). Here, it is determined whether or not the encoding process for one page has been completed (decision 208), and the determination 208
When the result is NO, the process returns to the process 204 and the process for the next block is executed.

When the encoding process for one page is completed and the result of the determination 208 is YES, the maximum one of the data amount CD (i) of each block is selected and set to the maximum value CDx. It is set (process 209).

Next, it is checked whether or not this maximum value CDx is T1a or more (decision 210). Judgment 21
When the result of 0 is YES, it means that the image of this page is complicated and there are many fine images. Therefore, with the transmission line density of the image of this page set to SSF (Processing 21
1) and this process ends. As a result, in the subsequent processing, the image of this page has the transmission line density treated as SSF, and after being temporarily stored in the image storage device 9,
It is sent to the specified destination.

When the result of the judgment 212 is NO, it is checked whether or not the maximum value CDx is larger than the predetermined value T2a (<T1a) (decision 212). If the result of determination 212 is YES, this means that the image of this page is relatively complicated and contains a somewhat fine image, so the transmission line density of the image of this page is set to DTL (process 213).

Next, the image data of one page having a linear density of SSF stored in the image buffer area is converted into linear image density data having a linear density of DTL by the image processing unit 7 (process 214). The DTL image data after the linear density conversion is stored in another image buffer area set in the system memory 2.

Then, the image data having the linear density DTL stored in the other image buffer area is encoded / decoded by the encoding / decoding unit 8.
The image information obtained by the encoding and compression is stored in the image storage device 9 (process 215). Further, the image information on this page is handled with the transmission line density set to DTL.

When the result of the judgment 212 is NO, it means that the image of this page does not have a complicated portion and does not include a very fine image. Therefore, the transmission line density of the image of this page is set to STD ( Process 216).

Next, the image processing unit 7 converts the image data for one page having a linear density of SSF stored in the image buffer area into image data having a linear density of STD (processing 217). The STD image data after the linear density conversion is stored in another image buffer area set in the system memory 2.

Then, the image data having the linear density STD stored in the other image buffer area is encoded / decoded by the encoding / decoding unit 8.
The image information obtained by the encoding and compression is stored in the image storage device 9 (process 218). Further, the image information on this page is handled with the transmission line density set to STD.

In this way, since the fineness of the image is judged based on the maximum value of the coded data amount of the image information in block units, the original image including a partially fine image is also judged. , It is possible to set an appropriate linear density. Further, in this case, since the image buffer area for temporarily storing the image data read by the scanner 4 is also used as the buffer area on the source data side at the time of linear density conversion, the memory utilization efficiency is good. .

Now, in the original image, for example, FIG.
In some cases, a halftone image PH such as a photograph is partially included as shown in FIG. Usually, the data amount of image information formed when the image of the halftone image PH is encoded and compressed is
Since it is much larger than the image of the non-halftone image part, if the linear density setting process described above is applied with this part included, the image information data in the part that does not include the fine image The amount becomes large, and there is a risk of misjudgment.

In order to prevent such an erroneous determination, it is necessary to determine the amount of image information data in the portion excluding the halftone image area.

On the other hand, if the halftone image is simply binarized with a fixed threshold value, halftone information is lost, and the image quality of this portion is deteriorated. Therefore, the halftone area of the image is determined, and for this halftone area, by applying pseudo halftone binarization processing such as dither binarization processing or binarization processing using the error diffusion method, There is a device that suppresses deterioration of image quality.

FIG. 8 shows an example of an image processing system of the scanner 4 having such a binarization processing function.

In the figure, the image reading unit 15 is
The original image is read at a linear density of 1 and the data of each pixel is output as image data of a predetermined number of bits. The image data PD includes halftone binarization unit 16 and fixed threshold binarization unit. 17, and image area separation unit 18
Has been added to.

The halftone binarization unit 16 uses the image data PD
Is, for example, a pseudo halftone binarization process using a systematic dither matrix threshold value, or a pseudo halftone binarization process such as a pseudo halftone binarization process to which an error diffusion method is applied. The output data is pseudo halftone binarized data B.
As Wp, it is added to one switching input terminal of the switching device 19.

The fixed threshold binarization unit 17 is used for the image data PD.
, The output data is added to the other switching input terminal of the switch 19 as the binary data BWs.

The image area separating unit 18 determines, based on the image data PD, whether the pixel currently being binarized is included in the halftone area or the non-halftone area. When it is determined to be included in the halftone region, the image area determination signal SL of data 0 is output, and when it is determined to be included in the non-halftone area, the image area determination signal S of data 1 is output.
Output L. The image area determination signal SL is applied to the control input terminal of the switch 19 and is also output to the system controller 1. A known image area separation technique can be used as a specific processing method of the image area separation unit 18. For example, if the image data has a density range that can be determined to be a halftone area, it can be determined that the pixel is included in the halftone area.

When the image area determination signal SL is data 0, the switch 19 selects the pseudo halftone binarized data BWp added to one of the switching input terminals, and at the same time, the image area determination signal. When SL is data 1, the binarized data BWs added to the other switching input terminal is selected, and its output is output to the system bus 12 as binarized data BW. ing.

Therefore, the binarization process for a pixel is performed by the halftone binarization unit 16 and the fixed threshold binarization unit 17, respectively, and the pseudo-halftone binarization data BWp and binarization data corresponding to the pixel are obtained. The binarized data BWs are output from the halftone binarization unit 16 and the fixed threshold binarization unit 17, respectively, and added to one switching input terminal and the other switching input terminal of the switcher 19.

Here, when the pixel to be binarized is included in the halftone area, the image area separation unit 1
From 8, the image area determination signal SL of data 0 is output.
As a result, the switching device 19 causes the pseudo halftone binarized data B
Wp is selected and output as binarized data BW.

When the pixel to be binarized is included in the non-halftone area, the image area separation section 18 outputs the image area determination signal SL of data 1. . Thereby, the switch 19 selects the binarized data BWs and outputs it as the binarized data BW.

In this way, the value of the binarized data BW becomes a value corresponding to the pixel area including the pixel to be binarized at that time.

FIG. 9 and FIG. 10 show an example of processing in this case from reading the transmission original for one page by the scanner 4 to saving it in the image storage device 9.

First, with the scanning linear density of the scan line 74 set to SSF (process 301), the scanner 4 is made to read and input one page of the original image, and at this time, the scanner 4 is read.
The image data output from is stored in a predetermined image buffer area formed in the system memory 2 (process 30).
2).

Next, the image data for one page stored in the image buffer area is encoded and compressed by the encoding / decoding unit 8 by a predetermined encoding method, and the image information for one page obtained by the encoding is compressed by the system. The image information is stored in a predetermined image information buffer area formed in the memory 2 (process 303),
Image area determination signal SL output from the scanner 4 at that time
Is input for each pixel and saved (processing 30
4).

Then, the value of the line counter Ln for storing the image line to be processed is initialized to 1 (process 305), and the line indicated by the value of the line counter Ln (hereinafter referred to as "Ln Line ")
Is a non-halftone line that does not include one or more halftone pixels, and is determined by referring to the storage result of the image area determination signal SL (decision 306).

When the result of determination 306 is YES, the code data amount CD (Ln) of the Ln-th line is
The contents stored in the image information buffer area are referenced and input (process 307), and the value of the code data amount CD (Ln) is integrated with the integrated value CDt (process 308). Also, judgment 3
When the result of 06 is NO, the processes 307 and 308 are not executed. As a result, the integrated value CDt stores the integrated value of the code data amount of the line in the non-halftone area.

Then, the value of the line counter Ln is incremented by 1 (process 309), the value of the line counter Ln is referred to check whether or not the processing for one page is completed (judgment 310), and the judgment 310 is made. When the result is NO, the process returns to the determination 306 and the process for the next line is executed.

When the processing of one page is completed and the result of the judgment 310 is YES, this integrated value CD
It is checked whether t is equal to or larger than the predetermined value T1b (decision 311). When the result of determination 311 is YES, the image of this page is complicated and there are many fine images. Therefore, with the transmission line density of the image of this page set to SSF (process 312), this process ends. . As a result, in the subsequent processing, the image on this page is
The transmission line density is treated as SSF, and the image storage device 9
Once stored in, the data is sent to the specified destination.

When the result of judgment 311 is NO, it is checked whether or not the integrated value CDt is larger than a predetermined value T2b (<T1b) (decision 313). When the result of the determination 313 is YES, it means that the image of this page is relatively complicated and includes a somewhat fine image, so the transmission line density of the image of this page is set to DTL (process 314).

Next, the image data for one page having a linear density of SSF stored in the image buffer area is converted into linear image data having a linear density of DTL by the image processing unit 7 (process 315). The DTL image data after the linear density conversion is stored in another image buffer area set in the system memory 2.

Then, the image data having the linear density DTL stored in the other image buffer area is encoded / decoded by the encoding / decoding unit 8.
The image information obtained by the encoding and compression is stored in the image storage device 9 (process 316). Further, the image information on this page is handled with the transmission line density set to DTL.

When the result of judgment 313 is NO, it means that the image of this page does not have a complicated portion and does not include a very fine image. Therefore, the transmission line density of the image of this page is set to STD ( Process 317).

Next, the image data for one page having a linear density of SSF stored in the image buffer area is converted into image data having a linear density of STD by the image processing unit 7 (processing 318). The STD image data after the linear density conversion is stored in another image buffer area set in the system memory 2.

Then, the image data having the linear density STD stored in the other image buffer area is encoded / decoded by the encoding / decoding unit 8.
The image information obtained by the encoding and compression is stored in the image storage device 9 (process 319). Further, the image information on this page is handled with the transmission line density set to STD.

In this way, according to the present embodiment, as shown in FIG.
As shown in (b), since the linear density of the original image at this time is determined based on the value obtained by integrating the code data amount line by line in the image area excluding the halftone area PH, it is more accurate. It is possible to set a high linear density.

11 and 12 show another example of processing from the reading of one page of the transmission original by the scanner 4 to the storage of the original in the image storage device 9.

First, with the reading linear density of the scan line 74 set to SSF (process 401), the scanner 4 is made to read and input one page of the original image.
The image data output from is stored in a predetermined image buffer area formed in the system memory 2 (process 40).
2).

Next, the image data for one page stored in the image buffer area is encoded and compressed by the encoding / decoding unit 8 by a predetermined encoding method, and the image information for one page obtained by this is compressed by the system. The image information is stored in a predetermined image information buffer area formed in the memory 2 (process 403),
Image area determination signal SL output from the scanner 4 at that time
Is input for each pixel and saved (process 40).
4).

Then, the value of the block counter Bn for storing the block to be processed is initialized to 1 (processing 405), and the value of the line counter Ln for storing the line to be processed is set to 1. Initialization is performed (process 406), and the line indicated by the value of the counter Ln (hereinafter referred to as “Ln-th line”) is 1
Whether the line is a non-halftone line that does not include one or more halftone pixels is determined by referring to the storage result of the image area determination signal SL (decision 407).

When the result of determination 407 is YES, the code data amount CD (Ln) of the Ln-th line is
The contents stored in the image information buffer area are referenced and input (process 408), and the value of the code data amount CD (Ln) is integrated with the block data integrated value BD (Bn) corresponding to the value of the block counter Bn. (Process 409). If the result of determination 407 is NO, the process 40
8 and processing 409 are not executed. As a result, the block data integrated value BD (Bn) is the integrated value of the code data amount of the line in the non-halftone area for each block (see FIG. 7C) corresponding to the value of each block counter Bn. Saved.

Next, the value of the line counter Ln is incremented by 1 (process 410), it is checked whether or not the process for one page is completed by referring to the value of the line counter Ln (process 411), and the process of process 411 is executed. When the result is NO, the value of the line counter Ln is referred to check whether or not the processing for one block is completed (decision 412). When the result of the determination 413 is NO, the process returns to the determination 407 and the process for the next line is executed. When the result of the determination 412 is YES, the value of the block counter Bn is incremented by 1 (process 413) and then the process returns to the determination 407, and the same process is executed for the next block.

When the processing of one page is completed and the result of judgment 411 is YES, the maximum value BDx of the block data integrated values BD (Bn) is obtained (judgment 414).

Then, it is checked whether or not the maximum value BDx is equal to or larger than the predetermined value T1c (decision 415). Judgment 4
When the result of 15 is YES, the image of this page is complicated and there are many fine images, and therefore the transmission line density of the image of this page is set to SSF (process 41).
6) and this process ends. As a result, in the subsequent processing, the image of this page has the transmission line density treated as SSF, and after being temporarily stored in the image storage device 9,
It is sent to the specified destination.

When the result of the judgment 415 is NO, it is checked whether or not the maximum value BDx is larger than the predetermined value T2c (<T1c) (judgment 417). When the result of determination 417 is YES, the image of this page is relatively complicated and includes a somewhat fine image, so the transmission line density of the image of this page is set to DTL (process 418).

Next, the image data for one page having a linear density of SSF stored in the image buffer area is converted into image data having a linear density of DTL by the image processing section 7 (processing 419). The DTL image data after the linear density conversion is stored in another image buffer area set in the system memory 2.

Then, the image data having the linear density DTL stored in the other image buffer area is encoded / decoded by the encoding / decoding unit 8
The image information obtained by the encoding and compression is stored in the image storage device 9 (process 420). Further, the image information on this page is handled with the transmission line density set to DTL.

If the result of judgment 417 is NO, it means that the image of this page has no complicated portion and does not include a very fine image. Therefore, the transmission line density of the image of this page is set to STD ( Process 421).

Next, the image data for one page having a linear density of SSF stored in the image buffer area is linearly density converted by the image processing unit 7 into image data having a linear density of STD (process 422). The STD image data after the linear density conversion is stored in another image buffer area set in the system memory 2.

Then, the image data having the linear density STD stored in the other image buffer area is encoded / decoded by the encoding / decoding unit 8.
The image information obtained by the encoding and compression is stored in the image storage device 9 (process 423). Further, the image information on this page is handled with the transmission line density set to STD.

In this way, in this embodiment, as shown in FIG.
As shown in (c), with respect to blocks A, B, C, and D obtained by equally dividing the original image into four in the sub-scanning direction, the code data amount of the image area excluding the halftone area PH is integrated line by line. Since the linear density of the original image at this time is determined based on the maximum value of the integrated values, a more accurate linear density can be set.

Further, for example, as shown in FIG. 7D, for blocks A, B, C, and D obtained by dividing the original image into four equal parts in the sub-scanning direction, the image areas other than the halftone area PH are displayed. By accumulating the code data amount in pixel units and determining the linear density of the original image at this time based on the maximum value of the integrated values, the linear density can be set more accurately. . In this case, for example, the image information is checked to determine the number of pixels in code data units, the pixel position is determined in the main scanning direction, the image area determination result is viewed in pixel units, and the pixel position becomes the halftone area. It is preferable to check whether or not it is included and to integrate the data amount of the code data determined as the non-halftone region.

Although the present invention is applied to the group 3 facsimile machine in the above-described embodiment, the present invention can be similarly applied to the group 4 facsimile machine.

In the above-mentioned embodiment, the case where the maximum linear density is SSF and the linear density (DTL) of 1/2 thereof and the linear density (STD) of 1/2 thereof are used, are explained. When applying a resolution other than
The present invention can be similarly applied. For example, even when the maximum resolution is 16 dots / mm in the main scanning direction and 14.5 lines / mm in the sub scanning direction, the present invention can be similarly applied.

[0102]

As described above, according to the present invention,
When the coded data amount of the image information after the coded compression is large, it is determined that the content of the image of the page is fine, and the image data with the maximum reading resolution is used as the transmission image data, and If the amount of encoded data is small, it is determined that the content of the image on the page is not very detailed, the image information is converted to lower resolution image data, and the converted image data is encoded and compressed to form image information. Is transmitted, the reading resolution is set according to the content of the document image, and as a result, it is possible to perform image transmission with good image quality and good transmission efficiency. In the case where an image reading device for discriminating the halftone region and outputting the binarized image data subjected to the pseudo halftone binarization processing is provided in the halftone region, the code of the part excluding the halftone region is indicated. Since the above determination process is performed based on the amount of data, an effect that an appropriate reading resolution can be set is obtained in this case as well.

[Brief description of drawings]

FIG. 1 is a block diagram showing a group 3 facsimile apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic diagram for explaining a pixel structure of each resolution.

FIG. 3 is a flowchart showing an example of a process from reading one page of a document image to saving the document image.

FIG. 4 is a schematic diagram for explaining a case where a document image is divided into blocks.

FIG. 5 is a flowchart showing a part of another example of the processing from the reading of one page of a document image to the storage thereof.

FIG. 6 is a flowchart showing another part of another example of the processing from the reading of one page of the document image to the storage thereof.

FIG. 7 is a schematic diagram for explaining processing when a halftone image is included.

FIG. 8 is a block diagram showing an example of a signal processing system of a scanner.

FIG. 9 is a flowchart showing a part of still another example of the processing from the reading of one page of a document image to the storage thereof.

FIG. 10 is a flowchart showing another part of still another example of the processing from the reading of one page of a document image to the storage thereof.

FIG. 11 is a flowchart showing a part of still another example of the processing from the reading of one page of a document image to the storage thereof.

FIG. 12 is a flowchart showing another part of still another example of the processing from the reading of one page of a document image to the storage thereof.

[Explanation of symbols]

 1 System Control Section 2 System Memory 4 Scanner 15 Image Reading Section 16 Halftone Binarization Section 17 Fixed Threshold Binarization Section 18 Image Area Separation Section 19 Switching Device

Claims (6)

[Claims] 1. An image reading device capable of binary reading an original image at the highest resolution among predetermined transmission resolutions, and binary image data obtained by reading the image reading device, with a lower resolution transmission resolution. And image processing means for converting the binarized image data into image information encoded and compressed by a predetermined encoding method, and encoding / decoding for decoding the image information into the original binary image data. And a data amount of the image information obtained when the binarized image data obtained by reading the original image for one page by the image reading device is encoded and compressed by the encoding / decoding device is larger than a predetermined value. If it is also small, the binarized image data is converted into low resolution binarized image data of a lower resolution transmission resolution by the image processing means, and the low resolution binarized image data is encoded / decoded. A facsimile apparatus comprising control means for using image information obtained by encoding and compression by stages as transmission image information. 2. An image reading device capable of binary reading an original image at the highest resolution among predetermined transmission resolutions, and binary image data obtained by the reading of the image reading device having a lower resolution. And image processing means for converting the binarized image data into image information encoded and compressed by a predetermined encoding method, and encoding / decoding for decoding the image information into the original binary image data. And a data amount of image information obtained when the binary image data obtained by reading one page of the original image by the image reading device is encoded and compressed by the encoding / decoding unit,
The original image is detected in block units divided in the sub-scanning direction of the image reading device, and when the maximum detected data amount is smaller than a predetermined value, two pages of one of the pages are detected. The binarized image data is converted to low resolution binarized image data having a lower transmission resolution by the image processing means, and the low resolution binarized image data is encoded and compressed by the encoding / decoding means. A facsimile apparatus comprising control means for using the obtained image information as transmission image information. 3. An image reading device capable of reading an original image in multi-gradation at the highest resolution among predetermined transmission resolutions, and multi-gradation image data output from the image reading device in a predetermined pseudo halftone. Pseudo-halftone binarization processing means for performing binarization processing, fixed threshold binarization means for binarizing multi-tone image data output from the image reading apparatus with a predetermined fixed threshold, and the image reading apparatus An image area separating unit that determines the multi-tone image data output from the image processing unit into a halftone area and a non-halftone area on a pixel-by-pixel basis, and a pixel that the image area separating unit determines to be a halftone area is the pseudo-intermediate area. While selecting the halftone binarized data output from the tone binarization processing means, the pixels which the image area separation means determines to be a non-halftone area are output from the fixed threshold binarization means. Select non-halftone binarized data An image synthesizing means, the binary image data output from the image synthesizing means,
Image processing means for converting to a lower resolution transmission resolution, and the binary image data output from the image synthesizing means is converted to image information coded and compressed by a predetermined coding method, and the image information is converted into original image information. Coding / decoding means for decoding into binarized image data, and binarized image data outputted from the image synthesizing means when the image reading device reads one page of a document image, to the above-mentioned coding / decoding. When the data amount of the image information obtained by encoding and compressing by the encoding means is smaller than a predetermined value, the binarized image data is converted by the image processing means into a low resolution binarization of a lower resolution transmission resolution. It is characterized by including control means for converting the image data into low-resolution binary image data and encoding and compressing the low-resolution binarized image data by the encoding / decoding means as transmission image information. Facsimile apparatus according to. 4. An image reading device capable of reading an original image in multi-gradation at the highest resolution among predetermined transmission resolutions, and multi-gradation image data output from the image reading device in a predetermined pseudo halftone. Pseudo-halftone binarization processing means for performing binarization processing, fixed threshold binarization means for binarizing multi-tone image data output from the image reading apparatus with a predetermined fixed threshold, and the image reading apparatus An image area separating unit that determines the multi-tone image data output from the image processing unit into a halftone area and a non-halftone area on a pixel-by-pixel basis, and a pixel that the image area separating unit determines to be a halftone area is the pseudo-intermediate area. While selecting the halftone binarized data output from the tone binarization processing means, the pixels which the image area separation means determines to be a non-halftone area are output from the fixed threshold binarization means. Select non-halftone binarized data An image synthesizing means, the binary image data output from the image synthesizing means,
Image processing means for converting to a lower resolution transmission resolution, and the binary image data output from the image synthesizing means is converted to image information coded and compressed by a predetermined coding method, and the image information is converted into original image information. Coding / decoding means for decoding into binarized image data, and binarized image data outputted from the image synthesizing means when the image reading device reads one page of a document image, to the above-mentioned coding / decoding. The data amount of the image information obtained when encoded and compressed by the encoding means is detected in block units formed by dividing the original image in the sub-scanning direction of the image reading device, and the maximum detected data amount is detected. If the value is smaller than the predetermined value, the binarized image data for one page of the page is converted into the low resolution binarized image data of the lower resolution by the image processing means. Facsimile apparatus characterized by converting, with a control means using the low-resolution binary image data as a transmission image information the image information obtained by compression coding by the coding and decoding means. 5. An image reading device capable of reading an original image in multi-gradation at the highest resolution among predetermined transmission resolutions, and multi-gradation image data output from the image reading device in a predetermined pseudo halftone. Pseudo-halftone binarization processing means for performing binarization processing, fixed threshold binarization means for binarizing multi-tone image data output from the image reading apparatus with a predetermined fixed threshold, and the image reading apparatus An image area separating unit that determines the multi-tone image data output from the image processing unit into a halftone area and a non-halftone area on a pixel-by-pixel basis, and a pixel that the image area separating unit determines to be a halftone area is the pseudo-intermediate area. While selecting the halftone binarized data output from the tone binarization processing means, the pixels which the image area separation means determines to be a non-halftone area are output from the fixed threshold binarization means. Select non-halftone binarized data An image synthesizing means, the binary image data output from the image synthesizing means,
Image processing means for converting to a lower resolution transmission resolution, and the binary image data output from the image synthesizing means is converted to image information coded and compressed by a predetermined coding method, and the image information is converted into original image information. Coding / decoding means for decoding into binarized image data, and binarized image data outputted from the image synthesizing means when the image reading device reads one page of a document image, to the above-mentioned coding / decoding. Of the data amount of the image information obtained when encoded and compressed by the encoding means, the data amount of the line excluding the line including the pixel determined to be the halftone area by the image area separating means is larger than the predetermined value. When it is small, the binarized image data is converted into low resolution binarized image data having a lower resolution transmission resolution by the image processing means, and the low resolution binarized image data is encoded. Facsimile apparatus characterized by comprising a control means for use as a transmission image information the image information obtained by compression coding by Goka means. 6. An image reading device capable of reading a document image in multi-gradation at the highest resolution among predetermined transmission resolutions, and multi-gradation image data output from the image reading device in a predetermined pseudo halftone. Pseudo-halftone binarization processing means for performing binarization processing, fixed threshold binarization means for binarizing multi-tone image data output from the image reading apparatus with a predetermined fixed threshold, and the image reading apparatus An image area separating unit that determines the multi-tone image data output from the image processing unit into a halftone area and a non-halftone area on a pixel-by-pixel basis, and a pixel that the image area separating unit determines to be a halftone area is the pseudo-intermediate area. While selecting the halftone binarized data output from the tone binarization processing means, the pixels which the image area separation means determines to be a non-halftone area are output from the fixed threshold binarization means. Select non-halftone binarized data An image synthesizing means, the binary image data output from the image synthesizing means,
Image processing means for converting to a lower resolution transmission resolution, and the binary image data output from the image synthesizing means is converted to image information coded and compressed by a predetermined coding method, and the image information is converted into original image information. Coding / decoding means for decoding into binarized image data, and binarized image data outputted from the image synthesizing means when the image reading device reads one page of a document image, to the above-mentioned coding / decoding. Of the data amount of the image information obtained when encoded and compressed by the encoding means, the data amount of the lines excluding the line including the pixel determined to be the halftone region by the image area separating means is the original image. Of the image reading device is detected in block units divided in the sub-scanning direction,
When the maximum amount of detected data is smaller than a predetermined value, the binarized image data for one page of the page is converted by the image processing means into a low resolution binary of a transmission resolution of a lower resolution. Converted into image data,
A facsimile apparatus comprising control means for using, as transmission image information, image information obtained by encoding and compressing the low-resolution binary image data by the encoding / decoding means.