JPH05167836A - Image processing device and facsimile equipment - Google Patents

Abstract

PURPOSE:To select the optimum halftone image processing function when facsimile communication is performed or an original image is duplicated by selecting a dither image processing function and an error diffusion image processing function as a halftone image processing function when the facsimile communication is performed or the original image is duplicated, and changing matrix data for dither image processing. CONSTITUTION:Image processing is performed in such a way that photoelectric conversion is applied to a reflected light of an original by an image sensor 21, and after distortion correction is applied to it at a distortion correction part 22. the light is outputted from an A/D conversion part 23 to a binarization processing part 24 and halftone processing parts A25, B26 as a digital picture signal. When a binary image processing mode is set, binary data processed at the binarization processing part 24 is outputted selectively by a multiplexer 28, and when halftone image copying is performed, the binary data processed at the halftone processing part A25 is outputted selectively by the multiplexer 28, and when a halftone image is transmitted, the binary data processed at the halftone processing part B26 is outputted selectively by the multiplexer 28.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus and a facsimile apparatus, and more particularly to an image processing apparatus and a facsimile apparatus for processing a halftone image by a dither processing method or an error diffusion method.

[0002]

2. Description of the Related Art Recently, in the information society, the number of devices handling image data has increased. An apparatus that handles such image data requires an image processing apparatus that converts pixel data read by a scanner or the like into a binary image signal. Recently, not only black and white binary images such as characters but also halftone images such as photographs are handled as images handled by the image processing apparatus.

Therefore, conventionally, when a halftone image is reproduced by binary output of black / white as in a facsimile machine, an area gradation expression utilizing the low-pass characteristic of human vision is performed, and a certain unit area is used. This is a method of expressing gradation by the black pixels inside, and since this unit area is usually composed of a minute area (1 mm x 1 mm) or less, white / black cannot be discriminated by human eyes, and as a halftone image. Be captured. Various methods have been proposed as a method of expressing gradation within this unit area.

As one of them, there is a dither method which has a light load on software and hardware. In this dither method, the level of each pixel of multi-value pixel data is compared with matrix data in which a plurality of predetermined threshold values are set. Then, binarization processing is performed based on the comparison result, and output binary pixel data is output to represent a halftone image. Further, in recent years, the demand for the image quality of a halftone image has been increased, and an error diffusion method which is excellent in gradation and resolution has also been adopted. In this error diffusion method, the result of diffusing a binarization error between output pixel data and input pixel data, which has been quantized for each pixel of multi-valued pixel data, into peripheral pixel data is based on a predetermined threshold value. Binarization processing is performed and output binary pixel data is output to represent a halftone image.

[0005]

However, in the halftone image processing in such a conventional facsimile apparatus, the error diffusion method has a problem that there are many isolated points due to the nature of the processing. In the dither method, white / black pixels are gathered to form an image to some extent, and thus the coding efficiency is better than that in the error diffusion method, but there is a problem that a binarization error occurs somewhat depending on how the matrix data is assembled. ..

Under these circumstances, the present demand is mainly for a copy image obtained by copying a document image, and the content of the transmitted image is understood. Most users are good enough, and it is desirable to use the halftone image processing function in consideration of these points. Further, as the conventional halftone image processing, for example, as in the image processing method and apparatus disclosed in Japanese Patent Laid-Open No. 1-218172, when the input image density data is judged to be white, the density saving type is used. Regardless of the binarized output of the binarization processing method, the binarized output of the input image density data is set to white to improve the coding efficiency, but the density is not saved between the input and output, and the image quality deteriorates. The problem remains.

Therefore, the present invention selects a dither image processing function and an error diffusion image processing function as a halftone image processing function during facsimile communication or original image copying, or changes matrix data for dither image processing, and It is an object of the present invention to provide an image processing apparatus and a facsimile apparatus that enable selection of an optimum halftone image processing function during communication and copying of an original image.

[0008]

The invention according to claim 1 is
In an image processing apparatus having a plurality of halftone image processing functions such as a dither image processing function and an error diffusion image processing function, a selection means for selectively selecting the plurality of halftone image processing functions is provided. According to a second aspect of the present invention, a communication means having a facsimile communication function, a copying means for copying a read original image on a recording paper, and a dither image processing function as a halftone image processing function during the facsimile communication and during the copying. A halftone image processing means having a plurality of halftone image processing functions such as a function and an error diffusion image processing function, and a selection means for selectively selecting the plurality of halftone image processing functions. The invention according to claim 3 is characterized in that a different halftone image processing function is selected by the selecting means during the facsimile communication and during the copying of the document. 5. The invention according to claim 4, wherein the halftone image processing function used in advance during the facsimile communication and the copy of the original document is initially set, and the initial setting can be changed by the selecting means. According to the invention, as a halftone image processing function, the level of each pixel of multi-valued pixel data is compared with matrix data in which a plurality of predetermined threshold values are set, and binarization processing is performed based on the comparison result and output 2 In an image processing apparatus having a dither image processing means for outputting value pixel data to express a halftone image, a data table for storing a plurality of the matrix data in which a plurality of different threshold values are set is provided, and The selecting means is provided for selecting the matrix data alternatively from the data table, and the matrix data is alternatively selected by the selecting means. According to a fifth aspect of the present invention, a communication unit having a facsimile communication function, a copying unit for copying a read original image on a recording sheet, and a facsimile communication process are performed. As a halftone image processing function at the time of copying, the level of each pixel of multi-valued pixel data is compared with matrix data in which a plurality of predetermined threshold values are set, and binarized based on the comparison result and output binary In a facsimile apparatus provided with a dither image processing unit for outputting pixel data to express a halftone image, a data table for storing a plurality of the matrix data in which a plurality of different threshold values are set is provided, and A selection means for selectively selecting matrix data from the data table is provided, and the selection means can be selected for the facsimile communication and the document copying. The halftone image processing is performed by selecting different matrix data depending on the stage, and the invention according to claim 6 is the invention according to claim 5, wherein a plurality of matrix data are stored in the data table. A dot dispersion type matrix in which different threshold values are dispersed and arranged in a matrix, and a dot concentration type matrix in which a plurality of different threshold values are arranged in series from one point in the matrix are provided. A centralized type matrix is selected, and at the time of copying, a dot dispersed type matrix is selected to execute halftone image processing. The invention according to claim 7 is the invention according to claim 6, The matrix data selection at the time of communication and copying is set as the initial setting, and the initial setting can be changed by the selecting means. Was that characterized by an invention of claim 8 includes a communication means having a facsimile communication function,
A copying unit for copying the read original image on a recording sheet, and a halftone image processing unit having a dither image processing function and an error diffusion image processing function as a halftone image processing function during the facsimile communication and copying are provided. The facsimile apparatus is provided with selection means for selectively selecting the dither image processing function and the error diffusion image processing function, the dither image processing function is selected during the facsimile communication, and the error diffusion image processing function is selected during the copying. The invention according to claim 9 is characterized in that, in the invention according to claim 8, the selection of the halftone image processing function at the time of the facsimile communication and at the time of copying is initialized, It is characterized in that the initial setting can be changed by the selecting means.

[0009]

In the image processing apparatus having a plurality of halftone image processing functions such as a dither image processing function and an error diffusion image processing function, the plurality of halftone image processing functions are selectively used. A selection means for selecting is provided. Therefore, the optimum halftone processing function can be selected according to the application of the image processing apparatus.

According to a second aspect of the present invention, a communication means having a facsimile communication function, a copying means for copying the read original image onto a recording sheet, and a dither image as a halftone image processing function during the facsimile communication and during the copying. In a facsimile apparatus including a halftone image processing means having a plurality of halftone image processing functions such as a processing function and an error diffusion image processing function, a selection means for selectively selecting the plurality of halftone image processing functions is provided. Different halftone image processing functions are provided by the selecting means provided at the time of facsimile communication and at the time of copying an original. Therefore, the optimum halftone image processing function can be selected in consideration of the transmission time of image information and the image quality.

According to a third aspect of the invention, in the second aspect of the invention, the halftone image processing function used in advance during facsimile communication and document copying is initialized, and the initial setting is changed by the selection means. It Therefore, the user who installs the facsimile apparatus can select the most suitable halftone image processing function according to the usage situation.

According to a fourth aspect of the invention, as a halftone image processing function, the level of each pixel of the multi-valued pixel data is compared with the matrix data in which a plurality of predetermined threshold values are set, and 2 is calculated based on the comparison result. In an image processing apparatus having a dither image processing means for performing binarization processing and outputting binary pixel data to express a halftone image, a plurality of the matrix data in which a plurality of different threshold values are set are stored. A data table is provided,
Selection means is provided for selecting the matrix data from the data table, and the selection means selectively selects the matrix data to perform halftone image processing.
Therefore, even in the image processing apparatus having only the dither image processing function, the matrix data suitable for the read image can be selected and processed, and the image quality of the reproduced image can be improved.

According to the present invention, a communication means having a facsimile communication function, a copying means for copying the read original image on a recording sheet, and a multi-valued halftone image processing function at the time of the facsimile communication and at the time of copying. A level of each pixel of pixel data is compared with matrix data in which a plurality of predetermined threshold values are set, and binarization processing is performed based on the comparison result, and output binary pixel data to express a halftone image. And a dither image processing means for performing the dither image processing, and a data table for storing a plurality of the matrix data in which a plurality of different threshold values are set is provided, and the matrix data is alternatively selected from the data table. A selection means is provided for selection, and the matrix differs depending on the selection means during facsimile communication and copy of an original. Halftone image processing is performed over data is selected and. Therefore, even in the facsimile apparatus having only the dither image processing function, the optimum matrix data can be selected in consideration of the transmission time of image information and the image quality.

According to a sixth aspect of the present invention, in the fifth aspect of the present invention, a plurality of matrix data stored in the data table is a dot dispersion type matrix in which a plurality of different threshold values are dispersed and arranged in a matrix. , A dot-concentrated matrix in which a plurality of different threshold values are arranged in series from one point in the matrix are provided, the dot-concentrated matrix is selected during facsimile communication, and the dot-dispersed matrix is selected during copying. Then, the halftone image processing is executed. Therefore, the transmission time of image information can be shortened without deteriorating the image quality during copying.

According to the invention of claim 7, in the invention of claim 6, the selection of the matrix data at the time of facsimile communication and at the time of copying is changed by the selecting means as an initial setting. Therefore, the user who installs the facsimile device can select the optimum matrix data according to the usage situation. According to an eighth aspect of the present invention, a communication unit having a facsimile communication function, a copying unit for copying the read original image on a recording sheet, and a dither image processing function as a halftone image processing function during the facsimile communication and during copying. In a facsimile apparatus including a halftone image processing unit having an error diffusion image processing function, a selection unit for selectively selecting the dither image processing function and the error diffusion image processing function is provided, and the dither image processing is performed during facsimile communication. The function is selected, and at the time of copying, the error diffusion image processing function is selected and the halftone image processing is executed. Therefore, the image quality of the transmitted image can be improved without increasing the transmission time of the image information.

According to a ninth aspect of the invention, in the eighth aspect of the invention, the selection means changes the selection of the halftone image processing function at the time of facsimile communication and at the time of copying as an initial setting. Therefore, the user who installs the facsimile apparatus can select the most suitable halftone image processing function according to the usage situation.

[0017]

EXAMPLES The present invention will be specifically described below based on examples. 1 to 6 are views showing an embodiment of a facsimile apparatus 1 to which the image processing apparatus and the facsimile apparatus of the present invention are applied. FIG. 1 is a block diagram of the facsimile device 1. The facsimile device 1 includes a control unit 2, a system memory 3, a parameter memory 4, a scanner 5, a plotter 6, a network control device 7, a modem 8, an image storage device 9, and a code. It is composed of an encryption / decryption device 10, an operation panel 11 and the like, and each unit is connected to a bus 12.

The control unit 2 controls each unit according to the basic program stored in the system memory 3 to execute the sequence as the facsimile apparatus 1, and also the scanner 5 according to the image processing program of the present invention stored in the system memory 3. Control = to execute halftone image processing of the read image. The system memory 3 stores a basic program of the facsimile apparatus 1 and an image processing program of the present invention, and constitutes a work area for storing various data necessary for executing these programs.

The parameter memory 4 stores various information unique to the G3 facsimile machine. The scanner 5 is shown in FIG.
As shown in, the image sensor 21, the distortion correction unit 22, the A / D
The conversion unit 23, the binary processing unit 24, the halftone processing unit A25, the halftone processing unit B26, the line buffer 27, and the multiplexer 28 are included. The image sensor 21 converts the reflected light from the document into an electric signal, and the distortion correction unit 22 corrects the nonuniformity (shading distortion) of the image signal caused by the variation of the light source, the image sensor 21 and the optical system. It is output to the A / D converter 23. The A / D conversion unit 23 quantizes the distortion-corrected image signal output from the distortion correction unit 22 and outputs it to the binary processing unit 24 as a digital image signal. The binary processing unit 24
Various processes for converting the digital image signal output from the A / D converter 23 into a binary image are executed. The halftone processing unit A25 performs predetermined halftone image processing according to the digital image signal output from the A / D conversion unit 23, but in this embodiment, it has an error diffusion processing function. The halftone processing unit B26 performs halftone image processing different from that of the halftone processing unit A25 according to the digital image signal output from the A / D conversion unit 23, but in the present embodiment, it has a dither processing function. And The line buffer 27 includes a distortion correction unit 22 and a binary processing unit.
24 holds data necessary for various arithmetic processes in the halftone processing unit A25 and the halftone processing unit B26. Multiplexer
28 is a binary processing unit 24 according to a control signal from the control unit 2,
One of the binary data output from the halftone processing unit A25 and the halftone processing unit B26 is selected and output.

Which image processing mode is selected from the binary processing section 24, the halftone processing section A25 and the halftone processing section B26 in the scanner 5 is determined by operating the selection key on the operation panel 11 described later. Shall be done. As the plotter 6, for example, a thermal recording device using a thermal element is used, and the plotter 6 records an image directly on a thermal recording paper or indirectly on an ordinary recording paper via an ink sheet.

The network control unit 7 is a so-called AA-NCU, and the network control unit has a line L (for example,
Telephone line) is connected. The network control unit automatically receives an incoming call from the line L and performs an automatic outgoing call process to the line L. The modem 8 is for realizing a modem function of G3 facsimile communication, and has a low-speed modem function (V.21 modem) for exchanging a transmission procedure signal and a high-speed modem function (for exchanging image information). V.29 modem, V.27ter modem).

The image storage device 9 is composed of a large-capacity hard disk device or the like, and stores encoded image information for transmission and received encoded image information, which is read at a predetermined time and transmitted. And recording processing is performed. The encoding / decoding unit 10 encodes image information according to a predetermined encoding method, and also decodes the encoded image information.

The operation panel (selection means) 11 is provided with various operation keys such as a numeric keypad and a start key, and is also provided with a display (for example, a liquid crystal display) from which various commands such as a transmission operation are inputted. On the display, the contents of the command input from the operation keys and various information notified to the operator from the facsimile device are displayed. Further, the operation panel 11 is provided with a selection key for selecting an image processing mode in the scanner 5.

Next, the operation will be described. The present embodiment is characterized in that the method of processing a halftone image performed by scanning the original image with the scanner 5 is changed during facsimile communication or copying. Hereinafter, this halftone image processing will be described focusing on the scanner 5 shown in FIG.

In FIG. 2, the original is irradiated with light from a light source (not shown), and the reflected light from the original is imaged on the image sensor 21 by an optical system (not shown) and photoelectrically converted so that the electric signal is a distortion correction unit. It is output to 22. After the electric signal is distortion-corrected by the distortion correction unit 22, it is quantized by the A / D conversion unit 23,
Binary processing unit 24 and halftone processing unit A25 as digital image signals
And to the halftone processing unit B26 for image processing. For example, when the binary image processing mode is selected, the binary data processed by the binary processing unit 24 is selected and output by the multiplexer 28, and when copying the halftone image, the halftone processing unit A25. The processed binary data is selected and output by the multiplexer 28, and when the halftone image is transmitted, the halftone processing unit B26.
The binary data processed in (1) is selected by the multiplexer 28 and output.

In the configuration of FIG. 2, two halftone processing units are provided, but it is possible to increase the number as needed. Further, the selection of the halftone processing method can be changed by operating the selection key from the operation panel 11 by preliminarily holding the initial setting in the system memory 3 so that the user who installs the facsimile apparatus 1 can do so as needed. It is possible to change the setting.

Further, FIG. 3 shows a configuration in which only the dither processing section is provided as a halftone processing function in the scanner 5.
In FIG. 3, the same parts as those in the scanner 5 shown in FIG. 2 are designated by the same reference numerals and the description thereof will be omitted.
In FIG. 3, the image processing unit in the scanner 5 is a comparator 3
1, a threshold register 32 and a threshold table (data table) A33 to C35, the digital image signal quantized by the A / D converter 23 is input to the comparator 31, and the threshold is given by the instruction of the controller 2. Binary data is output by being compared with a plurality of threshold levels in the threshold tables A33 to C35 set in the register 32.

Specifically, as in the threshold value table shown in FIG. 4A, a dot dispersion type (Bayer) type in which threshold value data of 0 to 16 are randomly dispersed and arranged,
As in the threshold table shown in FIG. 4B, a dot-concentrated type in which threshold data of 0 to 16 are spirally arranged from the center of the matrix is prepared. Each threshold value in each table corresponds to one pixel of the image, and the read image signal subjected to the distortion correction and A / D conversion is compared with the corresponding threshold level by the comparator 31 for each pixel. The threshold value register 32 normally holds threshold value data for one line in the sub-scanning direction. While the image signal on the same line is being processed, the threshold value data is cyclically set in the comparator 31, and when the processing line changes,
The threshold data of the next line is set in the threshold register 32, and the same processing is repeatedly executed. In this way, the binarization process is executed using the threshold value data of the periodic array, so that the halftone is reproduced by the ratio of black pixels in the area with the threshold value table as a unit. At this time, since the unit area is usually composed of 1 mm × 1 mm or less as described above, white / black in the unit area is not discriminated by human eyes and can be regarded as a halftone image. It should be noted that the threshold value table of FIG. 4 can express 16 gradations. (A) of FIG.
FIG. 4B shows an input image with a uniform density of 8 (8/16) in (b).
9A and 9B show an output example of binary image data when the dither processing is performed using the threshold tables of (a) and (b). At this time, in the comparator 31, when "input level> threshold level", black (1) Is output.

FIGS. 5A and 5B show that even with the same dither processing, the output image differs depending on the array of threshold data. That is, in the dot dispersion type, black pixels are discretely increased, whereas in the dot concentrated type, the adjacent dots are sequentially changed to black pixels, resulting in an image in which black pixels are dense. Generally, the dot dispersion type is excellent in resolution and the dot concentration type is excellent in gradation. However, in consideration of image transmission in the facsimile apparatus 1, the coding rate of the dot concentration type in which black pixels are close to each other Is winning. In addition, a dot dispersion type having excellent resolution is suitable for a pure halftone image. Due to the above image characteristics associated with the array of threshold data, by selecting the dot concentration type matrix during facsimile transmission, the coding rate can be increased and communication time can be shortened without degrading image quality, and during copying, By selecting the dot dispersion type matrix, it is possible to improve the image quality of the copy image.

The dot matrix can be selected by operating the selection key on the operation panel 11 to change the initial setting in the system memory 3. Further, having a plurality of threshold value tables A33 to C35 allows the control unit 2 to set the threshold value data in the predetermined threshold value tables A33 to C35 in the threshold value register 32 so that the threshold value register 32 can be shared, and the hardware configuration can be improved. There is no increase in

The halftone image processing in the scanner 5 will be described with reference to the flowchart shown in FIG. In FIG. 6, first, when the power of the facsimile apparatus 1 is turned on, various settings in the system are initialized (step S1), and the half tone processing unit in the scanner 5 shown in FIG. It is checked whether there is a mode setting change or the like for A25, B26 or the threshold value tables 33A to 35C shown in FIG. 3 (step S2).

When the setting is changed, the setting is changed (step S3), and it is checked whether the setting content is the halftone processing mode or the transmission mode (steps S4 and S).
5). If it is not halftone processing, the binary image processing mode is determined, and the binary data processed and output by the binary processing unit 24 is selected by the multiplexer 28 and transferred (steps S6 and S7), and all reading is performed. The processing in the binary processing unit 24 is repeatedly executed until the processing of the image data is completed, and this processing is completed (step S8).

On the other hand, when the halftone processing mode is set and the transmission mode is not set, the halftone processing mode A is set.
(Step S9), and when the halftone processing mode is set and the transmission mode is set, the halftone processing mode B is executed (step S10), and the halftone processing unit A25 of FIG.
The error diffusion process in the halftone processing unit B26 in FIG. 4 or the dot dispersion type dither process or the dot concentration type dither process in FIG. 4 is executed, and one binary data of these processes is selected by the multiplexer 28. Data is transferred (step S7), and the selected processing is repeatedly executed until the processing of all the read image data is completed, and this processing is ended (step S8).

At the time of the above initialization, it is assumed that the initial settings in the system memory 3 are as follows. Halftone processing A: Error diffusion processing method or dot dispersion type dither processing method Halftone processing B: Dither processing method or dot concentration type dither processing method Therefore, a plurality of halftone image processing functions in the scanner 5 of the facsimile apparatus 1 are operated on the operation panel. By making it changeable from 11, the installation destination user of the facsimile apparatus 1 can select the halftone image processing function according to the usage status, and selects the halftone image processing function suitable for the transmission mode or the copy mode. be able to.

As a result, the communication time can be shortened in the transmission mode without degrading the image quality, and the image quality of the copied image can be further improved in the copy mode.

[0036]

According to the invention described in claim 1, in an image processing apparatus having a plurality of halftone image processing functions such as a dither image processing function and an error diffusion image processing function, a plurality of halftone image processing functions are provided. Since the selecting means for selectively selecting is provided, the optimum halftone processing function can be selected according to the application of the image processing apparatus.

According to the second aspect of the present invention, there are provided a communication means having a facsimile communication function, a copying means for copying the read original image on a recording sheet, and a halftone image processing function during the facsimile communication and during the copying. In a facsimile apparatus including a halftone image processing unit having a plurality of halftone image processing functions such as a dither image processing function and an error diffusion image processing function, a selection for selectively selecting a plurality of halftone image processing functions Means is provided and different halftone image processing functions are selected by the selection means during facsimile communication and during document copying, so the optimum halftone image processing function should be selected in consideration of the transmission time and image quality of image information. You can

According to the invention of claim 3, in the invention of claim 2, the halftone image processing function used in advance during facsimile communication and document copying is initialized, and the initializing is performed by the selecting means. Since the setting can be changed, the user who installs the facsimile apparatus can select the most suitable halftone image processing function according to the usage status.

According to the invention described in claim 4, the level of each pixel of the multi-valued pixel data is compared with the matrix data in which a plurality of predetermined threshold values are set as the halftone image processing function, and based on the comparison result. In the image processing apparatus including the dither image processing means for expressing the halftone image by performing the binarization process and outputting the output binary pixel data, a plurality of matrix data in which a plurality of different threshold values are set are stored. A dither image is obtained by providing a data table for selecting a matrix data from the data table, and selecting a matrix data by the selecting means to perform the halftone image processing by selectively selecting the matrix data. Even in an image processing device having only a processing function,
The matrix data suitable for the read image can be selected and processed, and the quality of the reproduced image can be improved.

According to the present invention, there are provided a communication means having a facsimile communication function, a copying means for copying the read original image on a recording sheet, and a halftone image processing function during the facsimile communication and during the copying. A level of each pixel of the multi-valued pixel data is compared with matrix data in which a plurality of predetermined threshold values are set, and binarization processing is performed based on the comparison result, and output binary pixel data to output a halftone image. And a data table for storing a plurality of matrix data in which a plurality of different threshold values are set, and the matrix data is alternatively selected from the data table. A selection means is provided for selecting, and different matrix data is selected depending on the selection means during facsimile communication and document copying. Since-option to doing halftone image processing, even in the facsimile apparatus comprises only dithered image processing function, it is possible to select the optimum matrix data in consideration of the electrical transmission time and image quality of the image information.

According to the invention of claim 6, in the invention of claim 5, as a plurality of matrix data stored in the data table, a plurality of different threshold values are dispersed and arranged in a matrix. A matrix and a dot concentration type matrix in which a plurality of different threshold values are arranged in series from one point in the matrix are provided. The dot concentration type matrix is selected during facsimile communication, and the dot dispersion type matrix is selected during copying. Since the halftone image processing is selected and executed, the transmission time of image information can be shortened without degrading the image quality during copying.

According to the invention of claim 7, in the invention of claim 6, the selection of the matrix data at the time of facsimile communication and at the time of copying can be changed by the selecting means as an initial setting. The previous user can select the optimum matrix data according to the usage status. According to the invention described in claim 8, a communication means having a facsimile communication function, a copying means for copying the read original image on a recording sheet, and a dither image processing as a halftone image processing function during the facsimile communication and during the copying. Function and a halftone image processing means having an error diffusion image processing function, a facsimile apparatus is provided with a selection means for selectively selecting the dither image processing function and the error diffusion image processing function, and the dither image is used during the facsimile communication. Since the halftone image processing is performed by selecting the processing function and the error diffusion image processing function during copying, the image quality of the transmitted image can be improved without increasing the transmission time of image information.

According to the invention of claim 9, in the invention of claim 8, the selection of the halftone image processing function at the time of facsimile communication and at the time of copying can be changed by the selecting means as an initial setting. The user who installs the apparatus can select the most suitable halftone image processing function according to the usage situation.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of a facsimile apparatus to which an image processing apparatus and a facsimile apparatus according to the present invention are applied.

FIG. 2 is a block diagram of the scanner in FIG.

FIG. 3 is a block configuration diagram of another scanner in FIG.

FIG. 4 is a diagram showing an example of the configuration of a threshold table in FIG.

5 is a diagram showing an example of binary data processed by the threshold table of FIG.

FIG. 6 is a flowchart of halftone image processing by the image processing apparatus and the facsimile apparatus of the present invention.

[Explanation of symbols]

 1 Facsimile device 2 Control unit 3 System memory 4 Parameter memory 5 Scanner 11 Operation panel 21 Image sensor 22 Distortion correction unit 23 A / D conversion unit 24 Binary processing unit 25 Halftone processing unit A 26 Halftone processing unit B 27 Line buffer 28 multiplexer 31 comparator 32 threshold register 33 threshold table A 34 threshold table B 35 threshold table C

Claims (9)

[Claims] 1. An image processing apparatus having a plurality of halftone image processing functions such as a dither image processing function and an error diffusion image processing function, comprising a selecting means for selectively selecting the plurality of halftone image processing functions. An image processing device provided. 2. A communication means having a facsimile communication function, a copying means for copying a read original image on a recording sheet, and a dither image processing function or an error diffusion image as a halftone image processing function during the facsimile communication and during copying. In a facsimile apparatus including a halftone image processing unit having a plurality of halftone image processing functions such as a processing function, a selection unit for selectively selecting the plurality of halftone image processing functions is provided. A facsimile apparatus characterized in that different halftone image processing functions are selected by selecting means at the time of copying and at the time of copying an original. 3. The invention according to claim 2, wherein the halftone image processing function used in advance during the facsimile communication and the copy of the original document is initialized, and the initial setting can be changed by the selecting means. A facsimile machine characterized by. 4. As a halftone image processing function, the level of each pixel of multi-valued pixel data is compared with matrix data in which a plurality of predetermined threshold values are set, and binarized based on the comparison result and output. In an image processing apparatus having a dither image processing means for outputting binary pixel data to express a halftone image, a data table for storing a plurality of the matrix data in which a plurality of different threshold values are set is provided, and An image processing apparatus, characterized in that selection means for selectively selecting matrix data from the data table is provided and matrix data is selected by the selection means to perform halftone image processing. 5. A communication means having a facsimile communication function, a copying means for copying a read original image on a recording sheet, and a halftone image processing function at the time of the facsimile communication and at the time of copying, for each pixel of multivalued pixel data. A dither image processing means for comparing the level with matrix data in which a plurality of predetermined threshold values are set, binarizing based on the comparison result, outputting output binary pixel data, and expressing a halftone image; And a data table that stores a plurality of the matrix data in which a plurality of different threshold values are set, and a selection unit that selectively selects the matrix data from the data table, Different half-tone images can be selected by selecting different matrix data by selecting means during facsimile communication and original copy. Facsimile apparatus characterized by performing the process. 6. The invention according to claim 5, wherein, as a plurality of matrix data stored in the data table, a dot dispersion type matrix in which a plurality of different threshold values are dispersed and arranged, and a plurality of different threshold values are arranged. A dot concentration type matrix in which the dots are arranged in series from one point in the matrix, and the dot concentration type matrix is selected during the facsimile communication and the dot dispersion type matrix is selected during the copying. A facsimile machine characterized by executing processing. 7. The facsimile apparatus according to claim 6, wherein selection of matrix data at the time of the facsimile communication and at the time of copying is an initial setting, and the initial setting can be changed by the selecting means. 8. A communication means having a facsimile communication function, a copying means for copying a read original image on a recording sheet, and a dither image processing function and an error diffusion image as a halftone image processing function during the facsimile communication and during copying. A half-tone image processing unit having a processing function, and a facsimile apparatus comprising: a selection unit for selectively selecting the dither image processing function and the error diffusion image processing function. A facsimile apparatus, which selects an error diffusion image processing function at the time of copying and executes halftone image processing. 9. The invention according to claim 8, wherein selection of the halftone image processing function at the time of facsimile communication and copying is set as an initial setting, and the initial setting can be changed by the selecting means. Facsimile machine.