JP2003060896A - Picture processor, picture processing method, program for making computer conduct the method and computer readable recoding medium with recorded program therein - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform a double density thresholding conversion with less deterioration in picture quality and without requiring a large scale of memory and a large scale of arithmetic means. SOLUTION: When the double density thresholding conversion is performed, a feature amount extracting part 1903 obtains the feature of input picture data S1 with the amount of continuity of pixels equal to or more than a prescribed threshold and pixels less than the threshold as a feature amount. A threshold matrix generating part 1906 obtains the feature amount and generates the threshold matrix of horizontally and vertically two-by-two pixels per one pixel of input picture data S1 in the resolution of 2N (dpi). A comparison part 1909 determines a binary density for the portion of four pixels concerning one pixel of input picture data S1 based on the threshold matrix. A judging part 1907 selects first and second transmitting parts 1910 and 1911 for transmitting binary picture data which is processed by double density thresholding based on the feature amount by the minimum data amount and outputs them.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to image processing for digital image data, and more specifically, in a digital multi-function peripheral that combines functions of a copying machine, a facsimile, a printer, a scanner, etc. An image processing device, an image processing method, and a method for performing the gradation conversion processing and the density conversion processing at the same time when the resolution and gradation when inputting and the resolution and gradation when outputting using a printer are different. The present invention relates to a program executed by a computer, and a computer-readable recording medium recording the program.

[0002]

2. Description of the Related Art Conventionally, a digital copying machine for processing digitized image data from an analog copying machine has appeared, and the digital copying machine has not only the function as a copying machine but also the function of the copying machine. There are digital multi-function peripherals that combine various functions such as a facsimile function, a printer function, and a scanner function.

When a document image is read by a scanner function or the like and is printed out from a printer or the like, the read document image is subjected to predetermined image processing suitable for print output by an image processing section. During this image processing, if the resolution and gradation of the read image differ from the resolution and gradation at the time of print output, density conversion processing and gradation conversion processing are required.

An example of image processing in the case where a document image read by a scanner is n-valued image data and the resolution of the document image is increased and printed out from a printer will be described. A first method of converting such n-valued image data into binary image data having a double resolution is an enlargement process (Japanese Patent Laid-Open No. Hei 1
No. 0-327316), the resolution is doubled by using the same process (density conversion processing), and thereafter, binarization is performed by gradation conversion processing (Japanese Patent Laid-Open No. 09-294209). There is.

In the second method, the density conversion processing is performed after the gradation conversion processing in the reverse process of the first method. As described above, conventionally, these two different image processes, that is, the gradation conversion process and the density conversion process have been separately executed separately.

[0006]

However, in the first method, since the n-valued pixels are interpolated during the enlargement processing, the image finally output as the processing result is binary image data. Nevertheless, a large amount of memory was required to temporarily store the enlarged n-value image. In addition, an arithmetic unit having high performance is required to smoothly execute the interpolation of n-valued image data.

On the other hand, in the second method, the gradation conversion process
Since the density conversion processing is executed after the binarization and the pixel is interpolated using the binarized image data, there is a problem that the image information of n values cannot be fully utilized at the beginning and the image quality is deteriorated. It was

The present invention has been made in order to solve the above-mentioned problems of the prior art, and the double density binarization conversion process is performed with less deterioration of the image quality, and a large capacity memory and a large-scale arithmetic means are provided. An object is to provide an image processing device that can be executed without need, an image processing method, a program that causes a computer to execute the method, and a computer-readable recording medium that records the program.

[0009]

[Means for Solving the Problems]
In order to achieve the object, an image processing apparatus according to the invention of claim 1 converts a read image signal into a digitally converted image signal, or converts digitally generated image information into an image signal, and digitally In an image processing apparatus provided with a programmable arithmetic means for performing image processing so that the converted image signal can be output as a visible image, the arithmetic means is an n-value having a resolution of N (dpi). Input image data of (n> 2) to 2N
It has a function of performing a double-density binarization conversion process to binary output image data having a resolution of (dpi), and the arithmetic means has a characteristic of the input image data when executing the double-density binarization conversion process. A feature amount extraction unit that obtains a continuous amount of pixels that are equal to or greater than a predetermined threshold value and pixels that are less than the threshold value as a feature amount, and obtains the feature amount, and 1
A threshold matrix creating means for creating a threshold matrix of vertical 2 × horizontal 2 pixels per pixel, and a comparing means for determining a binarized density for 4 pixels for 1 pixel of the input image data based on the threshold matrix are provided. It is characterized by

According to the first aspect of the present invention, the continuous amount of pixels of the input image data is obtained as a feature amount, and a threshold matrix of 4 pixels each having 2 pixels vertically and horizontally is created to determine the binarized density of each pixel. This makes it possible to perform gradation conversion and density conversion at the same time, with little deterioration in image quality, and without requiring a large-capacity memory and a large-scale arithmetic means.

The image processing apparatus according to a second aspect of the present invention is the image processing apparatus according to the first aspect of the present invention, wherein the feature amount extraction means creates a plurality of threshold matrixes having a resolution of 2N (dpi). It is characterized in that it has an algorithm and that the algorithm can be switched by an external switching instruction.

According to the second aspect of the present invention, a plurality of algorithms for creating the threshold matrix can be switched, and the optimum algorithm is selected according to the type of input image data and the like, and the double density binary value is selected. The performance of the conversion processing can be improved.

The image processing apparatus according to a third aspect of the present invention is the image processing apparatus according to the second aspect of the invention, wherein the feature amount extraction means uses the algorithm to extract the edge degree of the input image data. The present invention is characterized in that four different filter operations are performed for each direction with image data as a pixel of interest, and the operation result with the largest absolute value is determined as the feature amount for that pixel.

According to the third aspect of the present invention, the feature amount can be easily obtained only by extracting the edge degree of the input image data using a plurality of filters, and the double density 2
The performance of the binarization conversion process can be improved.

According to a fourth aspect of the present invention, in the image processing apparatus according to the second aspect, the feature amount extracting means is given as the algorithm for the received image data of one line. The feature is that the threshold value and the pixel density are compared with each other, and the continuous amount of the pixels equal to or more than the threshold value and the pixels less than the threshold value is determined as the feature value.

According to the invention of claim 4, the feature amount can be easily obtained based on the continuous amount for each density of the pixel of the image data, and the performance of the double density binarization conversion process can be improved. .

The image processing apparatus according to a fifth aspect of the present invention is the image processing apparatus according to the first aspect, wherein the arithmetic means externally transmits binary image data having a resolution of 2N (dpi) in different transmission formats. A plurality of transmitting means, and a determining means for selecting and transmitting the transmitting means that can transmit with the smallest data amount to the outside based on the characteristic amount.

According to the fifth aspect of the present invention, the transmission format for image data of the double-density binary image data with the smallest data amount can be selected depending on the characteristics of the input image data, so that the transfer efficiency of the image data can be improved. It is possible to improve the image processing performance.

Further, in the image processing apparatus according to a sixth aspect of the present invention, in the invention according to the fifth aspect, one of the plurality of transmitting means has a sequence of white pixels and black pixels in the binary image data. It is characterized in that the quantity is expressed by a predetermined number of bits, and that the continuous quantity designates a white or black pixel by using a predetermined bit and transmits.

According to the invention of claim 6, the transmission 2
Since the continuity of the pixel densities of the value image data is expressed by a predetermined number of bits, it is possible to reduce the data amount when a large number of pixel densities are continuous.

Further, in the image processing apparatus according to the invention of claim 7, in the invention according to claim 5, one of the plurality of transmitting means corresponds to the same number of bits in a data string of a predetermined number of bits. It is characterized in that binary image data for pixels is packed and transmitted.

According to the invention of claim 7, the transmission 2
Since the pixel density is packed into each bit of the value image data, the data amount can be reduced when the pixel density is not continuous.

In the image processing method according to the present invention, the read image signal is converted into a digitally converted image signal, or the digitally generated image information is converted into an image signal, and the image signal is converted into a digital signal. In the image processing method of performing image processing so that the generated image signal becomes an image signal that can be output as a visible image, input image data of n value (n> 2) having a resolution of N (dpi) is converted into 2N (dp).
When performing the double density binarization conversion processing on the binary output image data having the resolution of i), the feature of the input image data is obtained as a feature amount of a continuous amount of pixels equal to or more than a predetermined threshold value and pixels below the threshold value. 2N by obtaining the feature amount extraction step and the feature amount
A threshold matrix creating step of creating a threshold matrix of vertical 2 × horizontal 2 pixels for each pixel of the input image data at a resolution of (dpi), and 2 pixels for 4 pixels for 1 pixel of the input image data based on the threshold matrix. And a comparison step of determining a threshold concentration.

According to the eighth aspect of the present invention, the continuous amount of pixels of the input image data is obtained as a feature amount, a four-pixel threshold matrix of two vertical and horizontal pixels is created, and the binarized density of each pixel is determined. Therefore, the gradation conversion and the density conversion can be simultaneously performed by a simple arithmetic processing, the deterioration of the image quality is small, and a large-capacity memory and a large-scale arithmetic means can be eliminated.

The image processing method according to a ninth aspect of the present invention is the image processing method according to the eighth aspect, wherein in the feature amount extracting step, a plurality of threshold matrixes having a resolution of 2N (dpi) are created. An algorithm is provided, and the algorithm can be switched based on a switching instruction.

According to the ninth aspect of the present invention, a plurality of algorithms for creating the threshold matrix can be switched, and the optimum algorithm is selected according to the type of input image data and the like, and the double density binary value is selected. The performance of the conversion processing can be improved.

The image processing method according to a tenth aspect of the present invention is the image processing method according to the ninth aspect, wherein the algorithm of the feature amount extracting step is to extract the edge degree of the input image data. It is characterized in that four different filter operations are performed for each direction with data as the pixel of interest, and the operation result with the largest absolute value is determined as the feature amount for that pixel.

According to the tenth aspect of the present invention, the feature amount can be easily obtained only by extracting the edge degree of the input image data by using a plurality of filters, and the double density binarization conversion processing is performed. The performance of can be improved.

Further, in the image processing method according to the invention of claim 11, in the invention of claim 9, the algorithm of the feature amount extraction step is such that a given threshold value is applied to the received image data for one line. And comparing the pixel densities with the pixel densities, and determining the continuous amount of pixels that are equal to or greater than the threshold value and pixels that are less than the threshold value as the feature value.

According to the eleventh aspect of the present invention, it is possible to easily obtain the feature amount based on the continuous amount for each density of the pixels of the image data, and it is possible to improve the performance of the double density binarization conversion process. .

An image processing method according to a twelfth aspect of the present invention is the image processing method according to the eighth aspect, wherein the double density is 2
After binarization conversion processing, an output step of selecting one of a plurality of transmission formats capable of transmitting binary image data having a resolution of 2N (dpi) with a minimum data amount based on the characteristic amount and outputting the same to the outside. It is characterized by having.

According to the twelfth aspect of the present invention, the transmission format for image data of the double-density binary image data with the smallest data amount can be selected depending on the characteristics of the input image data, so that the image data transfer efficiency can be improved. It is possible to improve the image processing performance.

Further, in the image processing method according to the thirteenth aspect of the present invention, in the invention according to the twelfth aspect, the transmission format of the output step is a predetermined continuous amount of white pixels and black pixels in the binary image data. It is characterized in that it is expressed by the number of bits, and that the continuous amount specifies a white pixel or a black pixel by using a predetermined bit and transmits.

According to the thirteenth aspect of the present invention, since the pixel density continuity of the binary image data to be transmitted is represented by a predetermined number of bits, it is possible to reduce the data amount when the pixel density is continuous. it can.

Further, in the image processing method according to the fourteenth aspect of the present invention, in the invention according to the twelfth aspect, the transmission format of the output step is a data string of a predetermined number of bits for pixels corresponding to the same number of bits. It is characterized in that binary image data is packed and transmitted.

According to the fourteenth aspect of the present invention, since the pixel density is packed into each bit of the binary image data to be transmitted, the data amount can be reduced when the pixel density is not continuous.

A computer program according to a fifteenth aspect of the present invention causes a computer to execute the method according to any one of the eighth to fourteenth aspects.

According to the invention of claim 15, claim 8
It is possible to cause a computer to execute the method described in any one of 14 to 14, and to perform using the computer, thereby improving the image processing performance.

Further, a computer-readable recording medium according to the invention of claim 16 is characterized in that the program according to claim 15 is recorded.

The recording medium according to the sixteenth aspect of the present invention, which records the program to be executed by the computer according to the fifteenth aspect, makes the program readable by the machine, thereby performing the operation of the fifteenth aspect. It can be realized by a computer.

[0041]

BEST MODE FOR CARRYING OUT THE INVENTION An image processing apparatus, an image processing method, a program for causing a computer to execute the method, and a computer-readable recording medium recording the program according to the present invention will be described below with reference to the accompanying drawings. A preferred embodiment will be described in detail.

First, the principle of the image processing apparatus according to this embodiment will be described. FIG. 1 is a block diagram functionally showing the configuration of the image processing apparatus according to the embodiment of the present invention. In FIG. 1, the image processing apparatus has a configuration including the following five units.

The above-mentioned five units are the image data control unit 100, the image reading unit 101 for reading the image data, and the image memory control unit 102 for controlling the image memory for storing the images to write / read the image data. An image processing unit 103 for performing image processing such as processing and editing on the image data, and an image writing unit 104 for writing the image data on a transfer sheet or the like.

Each of the above-mentioned units is centered on the image data control unit 100, an image reading unit 101, an image memory control unit 102, and an image processing unit 103.
And the image writing unit 104 are respectively connected to the image data control unit 100.

(Image Data Control Unit 100) The following is the processing performed by the image data control unit 100.

For example, (1) data compression processing (primary compression) for improving data bus transfer efficiency, (2)
Transfer processing of primary compressed data to image data, (3) image combining processing (image data from a plurality of units can be combined, and combining on a data bus is also included.), (4) image Shift processing (shifting of images in the main scanning and sub-scanning directions), (5) image area expansion processing (image area can be expanded to the periphery by an arbitrary amount), (6) image scaling processing (for example, 50% Or fixed magnification of 200%), (7) parallel bus interface processing,
(8) Serial bus interface processing (interface with a process controller 211 described later), (9) format conversion processing between parallel data and serial data, (10) interface processing with the image reading unit 101, (11) image processing Unit 10
Interface processing with 3.

(Image Reading Unit 101) The processing performed by the image reading unit 101 is as follows.

For example, (1) reading processing of reflected light from an original by an optical system, (2) CCD (Charge Cou)
conversion to electric signals in a piled device (charge-coupled device), (3) digitization processing in an A / D converter, (4) shading correction processing (processing for correcting uneven illuminance distribution of a light source), (5) ) Scanner γ correction processing (processing for correcting the density characteristic of the reading system) and the like.

(Image memory control unit 102) The following processes are performed by the image memory control unit 102.

For example, (1) interface control processing with the system controller, (2) parallel bus control processing (interface control processing with parallel bus), (3) network control processing, (4) serial bus control processing (plurality) External serial port control process),
(5) Internal bus interface control processing (command control processing with the operation unit), (6) Local bus control processing (ROM and R for starting the system controller)
AM, font data access control processing, (7) memory module operation control processing (memory module write / read control processing, etc.), (8) memory module access control processing (from multiple units) Memory access request arbitration processing), (9) Data compression / expansion processing (processing to reduce the amount of data for effective use of memory), (10)
Image editing processing (data clearing of memory area, image data rotation processing, image composition processing on memory, etc.).

(Image Processing Unit 103) The processing performed by the image processing unit 103 is as follows.

For example, (1) shading correction processing (processing for correcting unevenness in the illuminance distribution of the light source), (2) scanner γ correction processing (processing for correcting the density characteristic of the reading system), (3) MTF correction processing, ( 4) Smoothing, (5)
Arbitrary scaling processing in the main scanning direction, (6) density conversion (γ conversion processing: corresponding to density notch), (7) simple multi-value processing,
(8) Simple binarization process, (9) Error diffusion process, (10)
Dither processing, (11) dot arrangement phase control processing (dots to the right, dots to the left), (12) isolated point removal processing,
(13) Image area separation processing (color determination, attribute determination, adaptive processing), (14) density conversion processing, and the like.

(Image Writing Unit 104) The processing performed by the image writing unit 104 is as follows.

For example, (1) edge smoothing processing (jaggy correction processing), (2) correction processing for dot rearrangement,
(3) pulse control processing of image signals, (4) format conversion processing of parallel data and serial data, and the like.

(Hardware Configuration of Digital Multifunction Peripheral)
Next, a hardware configuration when the image processing apparatus according to the present embodiment constitutes a digital multi-function peripheral will be described. FIG. 2 is a block diagram showing an example of the hardware configuration of the image processing apparatus according to this embodiment.

In the block diagram of FIG. 2, the image processing apparatus according to the present embodiment includes a reading unit 201, a sensor board unit 202, and an image data control unit 2.
03, an image processor 204, a video data control unit 205, and an image forming unit (engine) 206. Further, the image processing apparatus according to this embodiment includes a process controller 211, a RAM 212, and a ROM 213 via the serial bus 210.

Further, the image processing apparatus according to the present embodiment is provided with an image memory access control section 221 and a facsimile control unit 224 via the parallel bus 220, and further, the image memory access control section 221.
Connected to the memory module 222, system controller 231, RAM232, ROM2
33 and an operation panel 234.

Now, the relationship between the above-mentioned components and the units 100 to 104 shown in FIG. 1 will be described. That is, the reading unit 201 and the sensor board
The unit 202 realizes the function of the image reading unit 101 shown in FIG. Similarly, the image data control unit 203 realizes the function of the image data control unit 100. Similarly, the image processor 204
The function of the image processing unit 103 is realized by.

Similarly, the video data control unit 205
The image writing unit 104 is realized by the image forming unit (engine) 206. Similarly, the image memory access control unit 221 and the memory module 2
The image memory control unit 102 is realized by 22.

Next, the contents of each component will be described. The reading unit 201 that optically reads a document is composed of a lamp, a mirror, and a lens, and collects the reflected light of the lamp irradiation on the document on the light receiving element by the mirror and the lens.

A light receiving element such as a CCD is a sensor
The image data, which is mounted on the board unit 202 and converted into an electric signal by the CCD, is converted into a digital signal and then output (transmitted) from the sensor board unit 202.

The image data output (transmitted) from the sensor board unit 202 is the image data control unit 203.
Is input (received) to. Functional device (processing unit)
The image data control unit 203 controls all transmission of image data between the data bus and the data bus.

The image data control unit 203 transfers image data between the sensor board unit 202, the parallel bus 220 and the image processor 204, and the process controller 21 for the image data.
1 and a system controller 231 that controls the entire image processing apparatus. In addition, RAM2
12 is used as a work area of the process controller 211, and the ROM 213 stores a boot program of the process controller 211.

The image data output (transmitted) from the sensor board unit 202 is the image data control unit 203.
Transfer (send) to image processor 204 via
Then, the signal deterioration due to the quantization into the optical system and the digital signal (signal deterioration of the scanner system) is corrected, and the result is output (transmitted) again to the image data control unit 203.

The image memory access control unit 221
It controls writing / reading of image data to / from the memory module 222. In addition, the parallel bus 220
Control the operation of each component connected to. RAM
232 is used as a work area of the system controller 231, and the ROM 233 stores a boot program of the system controller 231.

The operation panel 234 inputs processing to be performed by the image processing apparatus. For example, the type of processing (copying, facsimile transmission, image reading, printing, etc.) and the number of processings are input. As a result, the image data control information can be input.

Next, the read image data is stored in the memory module 222 and reused.
There are jobs that are not stored in the memory module 222, and each case will be described. As an example of accumulating in the memory module 222, when copying a plurality of originals, the reading unit 201 is operated only once and the image data read by the reading unit 201 is accumulated in the memory module 222. There is a method of reading the stored image data a plurality of times.

As an example in which the memory module 222 is not used, the read image data may be reproduced as it is when only one original is copied. Therefore, the memory module 222 by the image memory access control unit 221 is used. There is no need to access to.

First, when the memory module 222 is not used, the data transferred from the image processing processor 204 to the image data control section 203 is returned from the image data control section 203 to the image processing processor 204 again. The image processor 204 performs image quality processing for converting the luminance data by the CCD in the sensor board unit 202 into area gradation.

The image data after the image quality processing is transferred from the image processing processor 204 to the video / data control unit 205. Post-processing regarding dot arrangement and pulse control for reproducing dots are performed on the signal changed to the area gradation, and thereafter, a reproduced image is formed on the transfer paper in the image forming unit 206.

Next, the flow of image data when the image data is stored in the memory module 222 and additional processing is performed at the time of image reading, for example, rotation in the image direction, image composition, and the like will be described. The image data transferred from the image processor 204 to the image data control unit 203 is
It is sent from the image data control unit 203 to the image memory access control unit 221 via the parallel bus 220.

Here, the system controller 23
Image data and the access control of the memory module 222 based on the control of 1, the expansion of the print data of the external PC (personal computer) 223, the memory.
Image data is compressed / decompressed for effective use of the module 222.

The image data sent to the image memory access control section 221 is stored in the memory module 222 after data compression after predetermined image processing (details will be described later but is executed only when desired). The image data is read out as needed. The read image data is decompressed, restored to the original image data, and returned from the image memory access control unit 221 to the image data control unit 203 via the parallel bus 220.

After transfer from the image data control unit 203 to the image processor 204, image quality processing and video
The data control unit 205 performs pulse control, and the image forming unit 206 forms a reproduced image on the transfer paper.

In the flow of image data, the functions of the digital multi-function peripheral are realized by the bus control of the parallel bus 220 and the image data control unit 203. The facsimile transmission function performs image processing on the read image data by the image processing processor 204, and the image data control unit 2
03 and the parallel bus 220 to the facsimile control unit 224. The facsimile control unit 224 converts the data into a communication network and sends it to the public line (PN) 225 as facsimile data.

On the other hand, the received facsimile data is
The line data from the public line (PN) 225 is converted into image data by the facsimile control unit 224 and transferred to the image processor 204 via the parallel bus 220 and the image data control unit 203. In this case, no special image quality processing is performed, the video data control unit 205 performs dot rearrangement and pulse control, and the image forming unit 206 forms a reproduced image on the transfer paper.

In a situation in which a plurality of jobs, for example, a copy function, a facsimile transmission / reception function, and a printer output function operate in parallel, allocation of the usage right of the reading unit 201, the image forming unit 206 and the parallel bus 220 to the job is assigned to the system controller. 231 and the process controller 211.

The process controller 211 controls the flow of image data, and the system controller 231
Controls the entire system and manages the activation of each resource. The function selection of the digital multi-function peripheral is selected and input on the operation panel (operation unit) 234, and the processing contents such as the copy function and the facsimile function are set.

The system controller 231 and the process controller 211 communicate with each other via the parallel bus 220, the image data control unit 203 and the serial bus 210. Specifically, communication between the system controller 231 and the process controller 211 is performed by performing data format conversion for the data interface between the parallel bus 220 and the serial bus 210 in the image data control unit 203.

(Image Processing Unit 103 / Image Processing Processor 204) Next, an outline of processing in the image processing processor 204 constituting the image processing unit 103 will be described. FIG. 3 is a block diagram showing an outline of processing of the image processing processor 204 of the image processing apparatus according to the present embodiment.

In the block diagram of FIG. 3, the image processor 204 includes a first input I / F 301, a scanner image processing section 302, a first output I / F 303, and a second input I / F 303.
Input I / F 304 and output image processing unit (image quality processing unit) 3
05 and the second output I / F 306.

In the above structure, the read image data is sent to the first of the image processor 204 via the sensor board unit 202 and the image data control unit 203.
It is transmitted from the input interface (I / F) 301 to the scanner image processing unit 302.

The scanner image processing unit 302 aims to correct the deterioration of the read image data, and specifically, shading correction, scanner γ correction, MTF
Make corrections. Although it is not a correction process, a scaling process of enlargement / reduction can also be performed. When the correction process of the read image data is completed, the image data is transferred to the image data control unit 203 via the first output interface (I / F) 303.

At the time of outputting to the transfer paper, the image data from the image data control unit 203 is received from the second input I / F 304, and the image quality processing unit 305 performs the area gradation processing. The image data after the image quality processing is output to the video / data control unit 205 or the image data control unit 203 via the second output I / F 306.

The area gradation processing in the image quality processing unit 305 includes density conversion processing, dither processing, error diffusion processing, etc., and the area approximation of gradation information is the main processing. Once the image data processed by the scanner image processing unit 302 is stored in the memory module 222, various reproduced images can be confirmed by changing the image quality processing by the image quality processing unit 305.

For example, by changing (changing) the density of the reproduced image or changing the number of lines of the dither matrix, the atmosphere of the reproduced image can be easily changed. At this time, it is not necessary to read the image from the reading unit 201 again each time the process is changed, and the image data accumulated from the memory module 222 is read,
It is possible to quickly perform different processings many times.

In the case where the system is composed of a single scanner, the scanner image processing and the gradation processing are performed together and output to the image data control unit 203. The processing content can be changed in a programmable manner. The command control unit 307 manages switching of processing, change of processing procedure, and the like via the serial I / F 308.

Next, the internal structure of the image processor 204 will be described. FIG. 4 is a block diagram showing the outline of the internal configuration of the image processing processor 204 of the image processing apparatus according to this embodiment. In the block diagram of FIG. 4, the image processor 204 is provided with a plurality of input / output ports 401 for data input / output to / from the outside, and data input and output can be set arbitrarily.

Further, a bus switch / local memory group 402 is internally provided so as to be connected to the input / output port 401.
The memory control unit 403 controls the memory area to be used and the path of the data bus. The input data and the data for output are assigned to the bus switch / local memory group 402 as a buffer memory and stored in each, and the I / F with the outside is controlled.

Bus switch / local memory group 4
The processor array unit 404 performs various processes on the image data stored in 02, and the output result (processed image data) is stored again in the bus switch / local memory group 402. The processing procedure in the processor / array unit 404, parameters for processing, and the like are stored in the program RAM 405 and the data RA.
Exchanges with M406.

Program RAM 405, data RAM 4
The contents of 06 are transferred from the process controller 211 to the host buffer 407 through the serial I / F 408.
Downloaded to. The serial I / F 408 is the same as the serial I / F 308 in FIG. In addition, the process controller 211 uses the data R
The contents of AM 406 are read and the progress of processing is monitored.

When the processing contents are changed or the processing form required by the system is changed, the contents of the program RAM 405 and the data RAM 406 referred to by the processor array unit 404 are updated and dealt with.

(Image Data Control Unit 100 / Image Data Control Unit 203) Next, the image data control unit 1
The outline of the processing in the image data control unit 203 which configures 00 will be described. FIG. 5 is a block diagram showing an outline of processing of the image data control unit 203 of the image processing apparatus according to this embodiment.

In the block diagram of FIG. 5, the image data input / output control unit 501 is the sensor board unit 20.
The image data from 2 is input (received), and the image data is output (transmitted) to the image processor 204.
That is, the image data input / output control unit 501 is a component for connecting the image reading unit 101 and the image processing unit 103 (image processing processor 204),
It can be said that this is an exclusive input / output unit only for transmitting the image data read by the image reading unit 101 to the image processing unit 103.

Further, the image data input control section 502 inputs (receives) the image data whose scanner image has been corrected by the image processing processor 204. The input image data is subjected to data compression processing in the data compression unit 503 in order to improve transfer efficiency in the parallel bus 220. Then, the data is sent to the parallel bus 220 via the data conversion unit 504 and the parallel data I / F 505.

Parallel data I from the parallel bus 220
Since the image data input via the / F 505 has been compressed for bus transfer, it is sent to the data decompression unit 506 via the data conversion unit 504, and the data decompression processing is performed there. The decompressed image data is transferred to the image processor 204 by the image data output control unit 507.

The image data control unit 203 also has a conversion function of parallel data and serial data. The system controller 231 transfers data to the parallel bus 220, and the process controller 211 transfers data to the serial bus 210. The image data control unit 203 performs data conversion for communication between the two controllers.

The serial data I / F is the first serial data I / F 5 for exchanging data with the process controller 211 via the serial bus 210.
08 and the second serial data I / F 508 used for exchanging data with the image processor 204. By independently providing one system with the image processing processor 204, the interface with the image processing processor 204 can be made smooth.

The command control unit 510 controls the operation of each component and each interface in the above-mentioned image data control unit 203 according to the input instruction.

(Image Writing Unit 104 / Video Data Control Unit 205) Next, an outline of the processing in the video data control unit 205 forming a part of the image writing unit 104 will be described. FIG. 6 is a block diagram showing an outline of processing of the video / data control unit 205 of the image processing apparatus according to the present embodiment.

In the block diagram of FIG. 6, the video / data control unit 205 performs additional processing on the input image data according to the characteristics of the image forming unit 206. That is, the edge smoothing processing unit 601 performs the dot rearrangement processing by the edge smoothing processing, the pulse control unit 602 performs the pulse control of the image signal for dot formation, and forms the image data on which the above processing is performed. Output to the unit 206.

In addition to the conversion of image data, a format conversion function for parallel data and serial data is provided, and the video data control unit 205 alone can support communication between the system controller 231 and the process controller 211. That is, parallel data I / F 603 for transmitting / receiving parallel data, serial data I / F 604 for transmitting / receiving serial data, parallel data I / F 603, and serial data I / F 6
By including a data conversion unit 605 that converts the data received by 04 to each other, the formats of both data are converted.

(Image Memory Control Unit 102 / Image Memory Access Control Unit 221) Next, an image memory control unit 102, which constitutes a part of the image memory control unit 102,
The outline of the processing in the access control unit 221 will be described. FIG. 7 is a block diagram showing an outline of processing of the image memory access control unit 221 of the image processing apparatus according to this embodiment.

In the block diagram of FIG. 7, the image memory access control unit 221 manages the interface of the image data with the parallel bus 220, and accesses the image data to the memory module 222, that is, stores (writes) the image data. / Controls read-out and is mainly external P
Controls expansion of code data input from C223 into image data.

Therefore, the image memory access control unit 221 includes a parallel data I / F 701, a system controller I / F 702, a memory access control unit 703, a line buffer 704, a video control unit 705, and a data control unit 705. Compressor 706 and data decompressor 7
07, a data conversion unit 708, and a memory image processing unit (not shown).

Here, the parallel data I / F 701 is
It manages the image data interface with the parallel bus 220. In addition, the memory access control unit 703
Controls the access of the image data to the memory module 222, that is, the storage (writing) / reading.

The input code data is stored in the line buffer 704 in the local area. The code data stored in the line buffer 704 is the system controller I / F 70.
System controller 231 input via 2
The video control unit 705 expands the image data into image data on the basis of the expansion processing command.

The expanded image data or the image data input from the parallel bus 220 via the parallel data I / F 701 is stored in the memory module 222. In this case, the data conversion unit 708 selects the image data to be stored, the data compression unit 706 performs data compression to improve memory usage efficiency, and the memory access control unit 703 sets the address of the memory module 222. Image data is stored (written) in the memory module 222 while being managed.

To read the image data stored (stored) in the memory module 222, the memory access control unit 703 controls the read destination address,
The read image data is expanded by the data expansion unit 707. The decompressed image data is sent to the parallel bus 220.
When the data is transferred to, the data is transferred via the parallel data I / F 701.

The memory image processing section provided in the image memory access control section 221 executes predetermined image processing on the input image data. The memory image processing unit mainly executes image processing premised on storing image data in the memory module 222, and executes image processing before data compression by the data compression unit 706.

(Unit Configuration) Next, the unit configuration of the image processing apparatus according to the present embodiment will be described.
FIG. 8 is a block diagram showing an example of a unit configuration when the image processing apparatus is a digital multi-function peripheral. In addition, FIG.
FIG. 3 is a block diagram showing an example of a unit configuration when the image processing apparatus is a single printer.

As shown in FIG. 8, in the case of a digital multi-function peripheral, it is composed of three units, an image reading unit 101, an image engine control unit 800 and an image writing unit 104, and each unit is a single PCB.
Can be managed on the board.

The image reading unit 101 is a CCD 80.
1, an A / D conversion module 802, a gain control module 803, etc., and converts the optically read optical image information into a digital image signal.

The image engine control unit 800 mainly comprises a system controller 231, a process controller 211, and a memory module 222 in the image memory control unit 102, and includes an image processor 204, an image memory access control unit 221 and The image data control unit 203 that performs bus control is handled as a unit.

The image writing unit 104 has a structure including an image forming unit 206 centering on the video / data control unit 205.

In these unit configurations, when the specifications and performances of the image reading unit 101 are changed, the data interface is held by changing only the image reading unit 101 in the system of the digital multi-function peripheral. Units do not need to be changed. Also,
When the image forming unit (engine) 206 is changed,
The system can be reconstructed by changing only the image writing unit 104.

As described above, the units depending on the input / output devices form a system with different configurations, so that the system can be upgraded only by exchanging the minimum unit as long as the data interface is held.

In the stand-alone printer shown in FIG. 9, the same image forming unit (engine) 206 as that of the digital multifunction peripheral is used.
When using, a digital copying machine and an image writing unit 10
4 can be shared.

When the image processing apparatus is used as a single printer, the image reading unit 101 is not necessary, and the image reading unit 101 can be used because of the system configuration of the digital multi-function peripheral.
Remove. The image engine control unit 800 can achieve the function even if it is shared with the digital multi-function peripheral, but the specifications are exceeded. In addition, the image processor 204
Since it is unnecessary, it is possible to optimize the cost by configuring the optimal controller for the system on another board.

Image engine control unit 8 shown in FIG.
In the configuration of 00, each module (configuration unit) of the image processor 204, the image data control unit 203, and the image memory access control unit 221 is configured by an independent module. Therefore, the image engine control unit 80
Common module is used for general purpose by deleting unnecessary modules from 0 to controller. As described above, similar functions are realized by using a common module without separately creating a module for controlling the image engine and a module for the controller.

(Details of Image Processing) Next, contents of image processing of the image processing apparatus according to the present embodiment will be described. FIG. 10 is an explanatory diagram showing an outline (an example of a spatial filter) of the scanner of the image processing apparatus according to the present embodiment. The MTF correction function is realized by the configuration of the spatial filter.

In FIG. 10, when a two-dimensional spatial filter is constructed with filter coefficients A to Y, the input image data is filtered by the same arithmetic processing for all the images. ing. For example, when the spatial filter processing is performed centering on the input image data (i row, j column), the arithmetic processing with the corresponding coefficient is performed on the image of the i row, j column, respectively.
The pixel of (i, j) is calculated with the coefficient value M by (i, j +
The pixel of 1) is respectively calculated with the coefficient value N, and the calculation result in the filter matrix shows the pixel of interest (i,
It is output as the processing result of j).

If the pixel of interest is (i, j + 1), (i, j
The pixel of (j + 1) is calculated with the coefficient value M, and (i,
The pixel of (j + 2) is calculated with the coefficient value N, and the calculation result in the filter matrix is the pixel of interest (i, j +).
It is output as the processing result of 1).

The input image data is different, and the processing parameters are common. In this spatial filtering process, the coefficient values A to Y are not fixed,
The value can be arbitrarily changed according to the characteristics of the input image and the desired image quality. If it cannot be changed, the flexibility of the image processing function may not be secured.

Implementation in the image processor 204 is
Even if the coefficient value is downloaded from the process controller 211 and the configuration of the reading unit is changed and the characteristic of the read image deterioration is changed, the content of the data to be loaded can be changed to cope with the system change.

FIG. 11 is an explanatory diagram showing an outline of shading correction of the image processing apparatus according to the present embodiment.
Further, FIG. 12 is an explanatory diagram showing an outline of shading data of the image processing apparatus according to the present embodiment. Shading correction corrects non-uniformity of reflected light characteristics based on the illuminance distribution of the illumination system.Before reading the original, a reference white plate with uniform density is read and reference data for shading correction is generated.・
Based on the data, the reflection distribution depending on the reading position of the read image is normalized.

As shown in FIG. 12, the shading data has a different reflection distribution depending on the document reading position n. A white plate of uniform density is read dark at the end of the document reading position. Sn represents the white plate read signal level at the read position n, and the larger Sn is, the brighter the read was.

The shading correction corrects the unevenness of the light quantity distribution of the lamp by performing the same processing on the read image data for the position-dependent data. The S data shown in FIG. 11 is shading data generated by the white plate reading shown in FIG.
The D data shown in FIG. 11 is read image data of each reading line. Further, n indicates a reading position.

The C data is the data after the shading correction of the D data and is normalized by Cn = A * (Dn / Sn). Here, A is a normalization coefficient.

In the image processor 204,
S data stored in local memory, input D
A correction calculation is performed between Dn and Sn corresponding to the data.

(Data Flow) Next, a process of accumulating an image in the memory module 222 will be described.
13 and 14 are explanatory diagrams showing the data flow of the image processing apparatus as a digital multi-function peripheral with the processing of accumulating an image in the memory module 222 according to the present embodiment.

FIG. 13 shows the flow from the reading unit 201 to the memory module 222, and FIG. 14 shows the flow from the memory module 222 to the image forming unit 206. Note that each process is performed by the image data control unit 20.
This is done by controlling the data flow between the bus and the unit by the control of 3.

In FIG. 13, the reading unit 201 and the sensor board unit 202 perform reading control (step S1301). Next, the image data control unit 203 performs input processing and output control of image data (step S1302). Next, the image processing processor 204 performs an input I / F control process (step S1303), the above-mentioned scanner image process (step S1304), and an output I / F process (step S1305).

Next, again, the image data control unit 203
Performs image data input processing (step S13).
06), data compression (step S1307) and data conversion (step S1308).
/ F control processing is performed (step S1309).

Next, the image memory access control unit 2
21 performs parallel I / F control processing (step S1310), performs data conversion (step S1311),
Data compression (step S1312) is performed, and memory access control is performed on the memory module 222 (step S1313). As a result, the image data is stored in the memory module 222 (step S1314).

In FIG. 14, the image data stored in the memory module 222 (step S1
401) to the image memory access control unit 221
Performs memory access control (step S1
402), data expansion (step S1403) and data conversion (step S1404), and parallel I / F control processing is performed (step S1405).

Next, the image data control unit 203 performs parallel I / F control processing (step S140).
6), data conversion (step S1407) and data expansion (step S1408) are performed, and image data output control is performed (step S1409).

Next, the image processor 204
Input I / F control processing is performed (step S141
0), image quality processing is performed (step S1411), and output I / F control processing is performed (step S1412).

Next, the video data control unit 205
Edge smoothing processing is performed (step S1413), pulse control is performed (step S1414), and then
The image forming unit 206 performs an image forming process (step S
1415).

Scanner image processing is executed by the image processing processor 204 for the read image data, and image quality processing is executed by the image processing processor 204 for the image data to be output to the image forming unit 206.

Further, the scanner image processing and the image quality processing can be operated in parallel, the read image is executed for the facsimile transmission, and the image data stored in advance in the memory module 222 is processed in parallel with the contents of the image quality processing. It is possible to output to transfer paper while changing.

FIG. 15 and FIG. 16 are explanatory diagrams showing the data flow of the image processing apparatus with the processing of accumulating an image in the memory module 222 according to this embodiment. FIG. 15 shows the flow from the PC 223 to the memory module 222, and FIG.
A flow from the module 222 to the image forming unit 206 is shown.

In FIG. 15, the PC 223 outputs the image data (step S1501), the image memory access control unit 221 holds the image data in the line buffer (step S1502), and the video control (step S1503) is performed. Conversion (step S150
After 4), compression is performed (step S1505), and memory access control is performed on the memory module 222 (step S1506). Thereby,
The image data is stored in the memory module 222 (step S1507).

In FIG. 16, the memory module 2
Image data stored in step 22 (step S160
In contrast to 1), the image memory access control unit 221
Memory access control is performed (step S160
2), data expansion (step S1603) and data conversion (step S1604) are performed, and parallel I / O is performed.
F control processing is performed (step S1605).

Next, the video data control unit 205
Edge smoothing processing is performed (step S1606), pulse control is performed (step S1607), and then
The image forming unit 206 performs an image forming process (step S
1608).

In this way, the code data from the PC 223 is converted into the image data and the memory module 22
If the data is stored in 2, when outputting a plurality of copies, since the data development time is only once, the printing performance is improved as compared with the controller that performs the expansion processing each time.

The image data read from the memory module 222 is changed in post-processing by the video data control unit 205 to form reproduced images on a transfer sheet with a plurality of variations for the same image. it can. Furthermore, the edge smoothing processing of the video / data control unit 205,
It is not necessary to expand the code data into image data every time the parameter of the pulse control process is changed.

(Structure of Facsimile Control Unit 224) Next, the functional structure of the facsimile control unit 224 will be described. FIG. 17 is a block diagram showing the configuration of the facsimile control unit 224 of the image processing apparatus according to this embodiment.

In the block diagram of FIG. 17, the facsimile control unit 224 includes a facsimile transmission / reception unit 170.
1 and an external I / F 1702. Here, the facsimile transmission / reception unit 1701 converts the image data into a communication format and transmits it to an external line, and converts the external data back into image data to form an image forming unit via the external I / F 1702 and the parallel bus 220. Record and output at.

The facsimile transmission / reception unit 1701 includes a facsimile image processing unit 1703, an image memory 1704, a memory control unit 1705, a data control unit 1706, an image compression / expansion unit 1707, a modem 1708 and a network control device 1.
709 is included in the configuration.

Of these, regarding facsimile image processing,
The binary smoothing processing on the received image is performed by the edge smoothing processing unit 6 in the video / data control unit 205 shown in FIG.
At 01. Also, regarding the image memory 1704, regarding the output buffer function, the image memory access control unit 221 and the memory module 2
A part of the function is transferred to 22.

In the facsimile transmission / reception unit 1701 having the above-described structure, when the transmission of image data is started, the data control unit 1706 instructs the memory control unit 1705 to sequentially read the image data stored from the image memory 1704. Let out. The read-out image data is restored to the original signal by the facsimile image processing unit 1703, subjected to density conversion processing and scaling processing, and added to the data control unit 1706.

The image data added to the data control unit 1706 is code-compressed by the image compression / expansion unit 1707, modulated by the modem 1708, and then sent to the destination via the network control device 1709. Then, the transmitted image information is deleted from the image memory 1704.

At the time of reception, the received image is temporarily stored in the image memory 1704, and if the received image can be recorded and output at that time, it is recorded and output when the reception of one image is completed. Further, when a call is made during the copying operation and reception is started, the image memory 1704 is accumulated in the image memory 1704 until the usage rate reaches a predetermined value, for example, 80%, and the usage rate of the image memory 1704 becomes 80%. When it reaches, the writing operation being executed at that time is forcibly interrupted, and the received image is read from the image memory 1704 and recorded and output.

At this time, the received image read from the image memory 1704 is deleted from the image memory 1704, and the writing operation that was interrupted when the usage rate of the image memory 1704 drops to a predetermined value, for example, 10%, is resumed.
When all the writing operations are completed, the remaining received image is recorded and output. Further, after the write operation is interrupted, various parameters for the write operation at the time of interruption are internally saved so that it can be restarted, and the parameters are internally restored when restarted.

(Structure of SIMD type processor) FIG.
Is a SIMD provided in the image processor 204
It is explanatory drawing which shows schematic structure of a type arithmetic processing means (SIMD type processor). SIMD (Single Ins
truncation stream Multiple
Datastream) executes a single instruction in parallel for a plurality of data, and is composed of a plurality of PEs (processor elements).

Each PE has a register (Reg) 1801 for storing data, a multiplexer (MUX) 1802 for accessing the register of another PE,
Barrel shifter (Shift Expand) 180
3, a logical operation unit (ALU) 1804, an accumulator (A) 1805 for storing a logical result, and a temporary register (F) 1806 for temporarily saving the contents of the accumulator 1805.

Each register 1801 is connected to an address bus and a data bus (read line and word line), and stores an instruction code defining the process and data to be processed. The content of the register 1801 is input to the logical operation unit 1804, and the operation processing result is stored in the accumulator 1805. In order to take the result out of the PE, it is temporarily saved in the temporary register 1806. By extracting the contents of the temporary register 1806, the processing result for the target data can be obtained.

The instruction code is given to each PE in the same content, the data to be processed is given in a different state for each PE, and the adjacent P
The contents of the register 1801 of E are transferred to the multiplexer 18
With reference to 02, the calculation result is processed in parallel and output to each accumulator 1805.

For example, if the contents of one line of image data are arranged in the PE for each pixel and arithmetic processing is performed with the same instruction code, the processing result for one line can be obtained in a shorter time than when the pixels are sequentially processed. can get. In particular, in the spatial filter processing and the shading correction processing, the instruction code for each PE is the arithmetic expression itself, and the processing can be performed commonly to all PEs.

(Contents of Double-Density Gradation Processing) Next, the processing content of the double-density gradation processing executed by the image processor 204 will be described. FIG. 19 is a block diagram showing a configuration related to double density gradation processing inside the image processor 204.

As an example, 8-bit (256-value) image data having a resolution of 600 dpi is input from the image data control unit 203 to the image processing processor 204, and the image processing processor 204 outputs a binary value having a resolution of 1200 dpi. It is assumed that the image data is converted into image data and output to the video data control unit 205.

First, the user uses the operation panel 234 to
Select the type of original. The information necessary for the image processing processor 204 to execute the double-density binarization processing, such as the number of gradations of image data input to the image processing processor 204 and the total data transfer amount, is not limited to the type of document. Before the input of the image data S1 is started, the system controller 231 transmits the image data control unit 203 to the image data control unit 203, and the image data control unit 203 image-processes the command signal S3 together with the write request signal S2. It is transmitted to the control unit 1901 in the processor 204.

The control section 1901 controls the write request signal S2.
When it receives, the program data S5 of the feature quantity extraction algorithm is transferred from the feature quantity extraction algorithm storage unit 1902 to the feature quantity extraction unit 1903 according to the information obtained from the command signal S3. The Busy signal S3 is transmitted to the image data control unit 203 until all the procedures necessary for receiving the image data S1 are completed. When all the procedures are completed, the Ready signal S3 is transmitted, and the process waits until the image data S1 is input.

The image data control unit 203 transmits the write request signal S2 to the image processing processor 204, and then, within a certain fixed time, the Rea from the image processing processor 204.
If the dy signal S3 is not confirmed, an error is notified to the system controller 231.

The input image data S1 is temporarily stored in the speed conversion FIFO 1905 of the input unit 1904 and then sent to the feature amount extraction unit 1903. Feature quantity extraction unit 1
903 obtains the feature of the received image data by a scalar amount (hereinafter, feature amount S6) according to the program data S5 of the feature amount extraction algorithm transferred from the feature amount extraction algorithm storage unit 1902. The feature amount required to create the threshold matrix and the feature amount required to determine the transmission format of the binary image data can be extracted individually. As a simple example of the feature amount extraction algorithm, Is mentioned.

One is to extract the edge degree (the degree of shading) of the input image data, as shown in FIG.
Using the four filters shown in (d), a calculation process of multiplying the corresponding pixel by the numerical value of each filter is performed, and the calculation result with the largest absolute value is obtained as the feature amount S6 for that pixel.
To decide. The filter 2001 shown in FIG. 20A detects the edge degree in the left-right direction with the pixel of interest as the center.
Further, the filter 2002 of (b) is in the vertical direction, (c)
The filter 2003 of (3) detects the edge degree in the upper right lower left direction, and the filter 2004 (d) detects the edge degree of the lower right upper left direction. The feature amount S6 obtained by using these plural filters is
It is transmitted to the threshold matrix creating unit 1906.

In addition, with respect to the received image data S1 for one line, the given threshold value is compared with the pixel density,
The continuous amount of pixels that are greater than or equal to the threshold value and pixels that are less than the threshold value is the feature value S6.
To decide. The continuous amount of pixels is counted by a counter or the like. The feature amount S6 is a scalar amount representing the distribution of the low density portion and the high density portion in the input image data.
It is transmitted to the determination unit 1907.

A plurality of these algorithms are mounted and can be selected by a command signal S4 from the outside. Select the type of image data (image, character,
An appropriate algorithm can be selected according to the photograph line drawing, etc.).

Control unit 190 which received the command signal S4
1 instructs the feature amount extraction unit 1903 to load the program data S5 of the selected algorithm from the feature amount extraction algorithm storage unit 1902 and execute the process.

The threshold value matrix creating unit 1906 receives the feature value S5 obtained from the feature value extracting unit 1903, and inputs it according to the program data S7 of the threshold value matrix creating algorithm transferred from the threshold value matrix creating algorithm storage unit 1908. A threshold matrix S8 consisting of vertical 2 × horizontal 2 pixels for each pixel of the image data S1
To create.

The following method can be given as an example of the algorithm for determining the threshold value. The characteristic value S6 is used to correct the intermediate value of the input image data S1. In the case of the input image data S1, since the gray scale is 256, the intermediate value is 128. Then, the following arithmetic expression is executed.

F (x, y) = 128 + K × C (x, y)

However, F (x, y): corrected threshold value K: correction factor C (x, y): feature amount x, y: Position coordinates of the pixel of interest

By performing the filter calculation shown in FIG. 20, the feature amount for the input image data is obtained, and as a result, one feature amount is obtained for each pixel of the input image data. Then, a correction value {K × C (x, y)} having the feature amount as the weight shown in the above arithmetic expression is obtained, and added to the intermediate value 128.

After this, from one of the corrected feature quantities to 4
Two thresholds (2 × 2 threshold matrix) are obtained. Here, the threshold value is obtained by referring to the coefficient matrix 2101 consisting of vertical 16 × horizontal 16 shown in FIG. 21 and FIG. That is, after adding the intermediate value to the feature quantity, the coefficient matrix 21
The four values in 01 are added to obtain four threshold values. At this time, the coefficient matrix 2101 itself has a size of vertical 16 × horizontal 16, but uses four values of the matrix of vertical 2 × horizontal 2 therein.

Explaining with reference to FIGS. 21 and 22,
The feature value a of each pixel after addition of each intermediate value shown in FIG.
b, c, ... Are the coefficient matrices 2101 shown in FIG.
Add the four values of the corresponding pixels in. Figure 2
The coefficient a shown in FIG.
The four values A in the above are added. Similarly, the feature amount b in FIG.
Is added with four values shown in B of FIG. When the position of the feature amount shown in FIG. 21 is shifted vertically and horizontally by one pixel, the four values added to it are the coefficient matrix 21 shown in FIG.
Within 01, the values in both the vertical and horizontal directions are shifted by a factor of two and used.

The threshold value used when converting input image data of 256 gradations (white 0 to black: 255) into an image of 2 gradations (white: 0 and black: 1) is from 0 to 255. Can be considered. The smallest square matrix capable of expressing these 256 types of thresholds has a size of 16 vertical × 16 horizontal (the number of squares in the matrix is 256). Therefore, the coefficient matrix 2101 has a size of 16 vertical × 16 horizontal.

As described above, the coefficient matrix 2101 is used to add four more values to the feature quantity after the correction and the addition of the intermediate value, and the values are added periodically. The term "periodic" means that the position of the four values extracted from the coefficient matrix 2101 is shifted by 2 squares each time the pixel of interest is shifted by 1 pixel. This cycle is twice as long as the pixel of interest. Where the intermediate value 12
8 is a fixed amount of addition, and then the coefficient matrix 21
The four values when 01 is used are fluctuating addition amounts. Next, if the added result is a negative value, it is corrected to 0, and if it is 255 or more, it is corrected to 255.

Here, the coefficient matrix 21 shown in FIG.
The value of 01 is determined by the quality of the output image that the user expects (for example, a smooth image, a sharp image, etc.). Note that the effect cannot be obtained with a random value. The expected quality of the output image can be determined and selected based on the type of document selected by the user on the operation panel 234.

As an example of the arrangement of values, in the coefficient matrix 2101 for making a smooth image, the coefficients having similar values are arranged apart from each other. Further, in the coefficient matrix 2101 for producing a sharp image, a positive coefficient is biased at the center of the matrix and a negative coefficient is biased at the ends.

The comparison unit 1909 determines the binarized density for four pixels for one pixel of the input image data S1 by using the threshold matrix S8 consisting of vertical 2 × horizontal 2 pixels. The image data output from the comparison unit 1909 is binary image data S9 (binary, 2NDpi) whose resolution is double that of the input image data S1 (n value, NDpi).
Becomes

The binary image data S9 is output to the outside after being converted into a format in which transmission is completed with the smallest amount of data. A first transmission unit 1910 and a second transmission unit 1911 are installed inside the image processing processor 204, and the image data S9 output from the comparison unit 1909 is
The transmission formats S10 and S11 are different from each other.

23 and 24 show the first transmitting section 19
It is a figure which shows the transmission data S10 converted by 10. As shown in FIG. 23, this transmission data S10 has 8 bits.
The continuous amount of white pixels and black pixels in the binary image data is represented by 7 bits. FIG. 24 is a diagram for explaining the continuous amount, and the continuous state and continuous amount of pixels for binary image data of white and black have the illustrated relationship (numerical value). FIG. 23
In, the most significant bit (MSB) indicates whether the continuous amount is a white pixel (0) or a black pixel (1). The transmission data S10 has a small data amount when the continuous amount is large.

The transmission data S11 converted by the second transmission section 1911 is composed of 8 bits, and the binary image data for 8 pixels is packed. Transmission data S11
Is a small amount of data when the continuous amount is small.

The transmission formats S1 and S2 used when outputting to the outside are determined by the determination unit 1907. The determination unit 1907 selects one of the formats S1 and S2 that can complete the transmission with the smallest data amount from the feature amount S6 obtained by the feature amount extraction unit 1903.

In the case of the above configuration example, the characteristic amount S6 representing the distribution of the low density portion and the high density portion in the image data S1 input to the image processing processor 204 is obtained. When the continuous amount of the low-density portion and the high-density portion is large, the first transmitting unit 1
The output unit 19 outputs the binary image data S10 converted in 910.
Send to 12. On the contrary, when the continuous amount is small, the binary image data S11 converted by the second transmission unit 1911 is sent to the output unit 1912. The determination unit 1907 notifies the output unit 1912 via the control unit 1901 of information S14 as to which transmission format the binary image data S10 and S11 are sent.

The output unit 1912 outputs the judgment units 1907 to 2
The value image data S1 and S2 are received, and the control unit 1901
Receives the information S14 regarding the transmission format, and outputs the image data S12 and the transmission format identification signal S13 in response to a request from the outside.

[0189] Note that each component relating to the image processing described in this embodiment can be realized by executing a program prepared in advance on a computer such as a personal computer or a workstation. This program is recorded on a computer-readable recording medium such as a hard disk, a floppy (R) disk, a CD-ROM, an MO, or a DVD, and is executed by being read from the recording medium by the computer. Further, this program can be distributed through the recording medium and a network such as the Internet.

[0190]

As described above, according to the first aspect of the invention, the read image signal is converted into a digitally converted image signal, or the digitally generated image information is converted into an image signal. In an image processing apparatus provided with a programmable arithmetic means for converting and digitally converting the image signal into an image signal that can be output as a visible image, the arithmetic means is N (dp
i) The function of performing n-valued (n> 2) input image data having a resolution into binary output image data having a resolution of 2N (dpi) by double density binarization conversion processing, In addition, when executing the double density binarization conversion process, a feature amount extraction unit that obtains a feature amount of a pixel of the input image data that is a continuous amount of pixels that are equal to or more than a predetermined threshold value and a pixel that is less than the threshold value is obtained, And threshold value matrix creating means for creating a threshold value matrix of vertical 2 × horizontal 2 pixels for each pixel of the input image data at a resolution of 2N (dpi), and 4 pixels for 1 pixel of the input image data based on the threshold matrix. And a comparison means for determining the binary density for each pixel. Therefore, the continuous amount of pixels of the input image data is obtained as a feature amount, and a threshold matrix of 4 pixels each having 2 pixels in the vertical and horizontal directions is created to generate each pixel. Binary density Achieved by determining, less deterioration of the image quality, and without the need for memory and large computing means large, an effect of executing the gradation conversion and density conversion simultaneously.

According to the invention of claim 2, claim 1
In the invention described in [3], the feature amount extraction means is 2N.
Since a plurality of algorithms for creating a threshold matrix having a resolution of (dpi) are provided and the algorithms can be switched by an external switching instruction, a plurality of algorithms for creating the threshold matrix can be switched. Therefore, there is an effect that an optimum algorithm can be selected according to the type of input image data and the like to improve the performance of the double density binarization conversion process.

According to the invention of claim 3, claim 2
In the invention described in (1), the feature amount extraction means performs, as the algorithm, four filter operations that are different for each direction in which the image data is a target pixel in order to extract the edge degree of the input image data, and an absolute value is calculated. Has a configuration in which the largest calculation result is determined as the feature amount for the pixel, so that the feature amount can be easily obtained only by extracting the edge degree of the image data input using a plurality of filters, This has the effect of improving the performance of the double-density binarization conversion process.

According to the invention of claim 4, claim 2
In the invention described in (1), the feature amount extraction means, as the algorithm, compares a given threshold value and a pixel density with respect to the received image data of one line, and continuously connects pixels equal to or more than the threshold value and pixels less than the threshold value. Since the amount is determined to be the feature amount, the feature amount can be easily obtained based on the continuous amount for each density of the pixels of the image data.
This has the effect of improving the performance of the binarization conversion process.

According to the invention of claim 5, claim 1
In the invention described in (1), the calculating means is 2N (dp
i) a plurality of transmitting means for externally transmitting binary image data having a resolution in different transmission formats, and based on the characteristic amount,
Since the configuration is such that the transmission means that can transmit with the smallest amount of data is selected and the determination means that outputs to the outside is provided, the transmission with which the double-density binary image data is imaged with the smallest amount of data depending on the characteristics of the input image data. Since the format can be selected, the transfer efficiency of the image data can be improved, and the image processing performance can be improved.

Further, according to the invention of claim 6, claim 5
In one aspect of the invention described above, one of the plurality of transmission means represents a continuous amount of white pixels and black pixels in the binary image data by a predetermined number of bits, and the continuous amount is expressed by using a predetermined bit. Since the configuration is such that the white or black pixels are designated and transmitted, the consecutive pixel densities of the binary image data to be transmitted are expressed by a predetermined number of bits, so that the data amount can be reduced when a large number of pixel densities are consecutive. Has the effect.

According to the invention of claim 7, claim 5
In the invention described in (1), since one of the plurality of transmitting means is configured to stuff and transmit binary image data of pixels corresponding to the same number of bits in a data string of a predetermined number of bits, a binary value to be transmitted. Since the pixel density is packed into each bit of the image data, there is an effect that the data amount can be reduced when the pixel density is not continuous.

According to the invention of claim 8, the read image signal is converted into a digitally converted image signal,
Alternatively, in an image processing method of converting digitally generated image information into an image signal and performing image processing so that the digitally converted image signal becomes an image signal that can be output as a visible image, a resolution of N (dpi) is set. N value (n>)
When the input image data of 2) is subjected to the double density binarization conversion processing to the binary output image data having a resolution of 2N (dpi), the characteristics of the input image data are set to the pixels which are equal to or more than a predetermined threshold value and less than the threshold value. Feature amount extraction step of obtaining a continuous amount of pixels as the feature amount, and obtaining the feature amount, and creating a threshold matrix of vertical 2 × horizontal 2 pixels for each pixel of the input image data with a resolution of 2N (dpi). A threshold matrix creating step,
Since the configuration includes a comparison step of determining the binarized densities of four pixels for one pixel of the input image data based on the threshold matrix, the continuous amount of pixels of the input image data is obtained as a feature amount, Since a threshold matrix of 4 pixels for each pixel is created and the binarized density of each pixel is determined, gradation conversion and density conversion can be performed simultaneously with simple arithmetic processing.
The image quality is less deteriorated, and a large-capacity memory and a large-scale arithmetic means can be eliminated.

Further, according to the invention of claim 9, claim 8 is provided.
In the invention described in the paragraph 3, in the feature amount extraction step, 2N
Since a plurality of algorithms for creating a threshold matrix having a resolution of (dpi) are provided and the algorithms can be switched based on the switching instruction, a plurality of algorithms for creating the threshold matrix can be switched. An effect that the performance of the double-density binarization conversion process can be improved by selecting the optimum algorithm according to the type of input image data and the like.

According to a tenth aspect of the invention, in the invention of the ninth aspect, the algorithm of the feature amount extracting step focuses on the image data to extract the edge degree of the input image data. Different for each pixel direction 4
Since the filter result is calculated for a single image and the calculation result with the largest absolute value is determined as the feature amount for that pixel, it is possible to use only multiple filters to extract the edge degree of the input image data. The amount can be easily obtained, and the performance of the double-density binarization conversion process can be improved.

According to an eleventh aspect of the invention, in the invention of the ninth aspect, the algorithm of the feature amount extracting step is such that, for the received image data for one line, a given threshold value and pixel density are given. And the continuous amount of pixels that are equal to or larger than the threshold value and the pixels that are less than the threshold value are determined to be the feature amount. Therefore, the feature amount can be easily obtained based on the continuous amount for each density of the pixels of the image data. Therefore, it is possible to improve the performance of the double-density binarization conversion process.

According to the twelfth aspect of the invention, in the eighth aspect of the invention, the binary image data having a resolution of 2N (dpi) after the double density binarization conversion process is
Since the configuration includes an output step of selecting one of a plurality of transmission formats that can be transmitted with the smallest data amount based on the characteristic amount and externally outputting the same, the double-density binary image data is Since it is possible to select the transmission format in which the image data is transmitted with the smallest amount of data, the transfer efficiency of the image data can be improved, and the image processing performance can be improved.

According to the thirteenth aspect of the present invention, in the invention of the twelfth aspect, the transmission format of the output step is a predetermined amount of consecutive white and black pixels in the binary image data. Since the image data is expressed and the continuous amount is designated and transmitted by designating the white or black pixel, the continuous pixel density of the binary image data to be transmitted is expressed by the predetermined number of bits. When a large number of pixel densities are continuous, the data amount can be reduced.

According to the invention of claim 14, in the invention of claim 12, the transmission format of the output step is a binary image of pixels corresponding to the same number of bits in a data string of a predetermined number of bits. Since the data is packed and transmitted, the pixel density is packed in each bit of the binary image data to be transmitted, so that the data amount can be reduced when the pixel density is not continuous.

Further, according to the fifteenth aspect of the present invention, since the method according to any one of the eighth to fourteenth aspects is configured to cause a computer to execute, the gradation conversion and the density conversion are simultaneously performed using the computer. Since it can be executed, the effect of improving the image processing performance can be achieved.

According to the sixteenth aspect of the present invention, since the program described in the fifteenth aspect is recorded, the program can be machine-readable, whereby the operation of the fifteenth aspect can be performed by a computer. There is an effect that can be realized.

[Brief description of drawings]

FIG. 1 is a block diagram functionally showing a configuration of an image processing apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing an example of a hardware configuration of the image processing apparatus according to the present embodiment.

FIG. 3 is a block diagram showing an outline of processing of an image processing processor of the image processing apparatus according to the present embodiment.

FIG. 4 is a block diagram showing an outline of an internal configuration of an image processing processor of the image processing apparatus according to the present embodiment.

FIG. 5 is a block diagram showing an outline of processing of an image data control unit of the image processing apparatus according to the present embodiment.

FIG. 6 illustrates a video of the image processing apparatus according to the present embodiment.
It is a block diagram which shows the outline | summary of a process of a data control part.

FIG. 7 is a block diagram showing an outline of processing of an image memory access control unit of the image processing apparatus according to the present embodiment.

FIG. 8 is a block diagram showing an example of a unit configuration of the image processing apparatus according to the present embodiment.

FIG. 9 is a block diagram showing another example of the unit configuration of the image processing apparatus according to the present embodiment.

FIG. 10 is an explanatory diagram showing an outline (an example of a spatial filter) of the scanner of the image processing apparatus according to the present embodiment.

FIG. 11 is an explanatory diagram showing an outline of shading correction of the image processing apparatus according to the present embodiment.

FIG. 12 is an explanatory diagram showing an outline of shading data of the image processing apparatus according to the present embodiment.

FIG. 13 is an explanatory diagram showing an example of a data flow of image data of the image processing apparatus according to the present embodiment.

FIG. 14 is an explanatory diagram showing another example of the data flow of image data of the image processing apparatus according to the present embodiment.

FIG. 15 is an explanatory diagram showing another example of the data flow of the image data of the image processing apparatus according to the present embodiment.

FIG. 16 is an explanatory diagram showing another example of the data flow of the image data of the image processing apparatus according to the present embodiment.

FIG. 17 is a block diagram showing the configuration of a facsimile control unit of the image processing apparatus according to the present embodiment.

FIG. 18 is an explanatory diagram showing a schematic configuration of a SIMD type processor used in the image processing apparatus according to the embodiment of the present invention.

FIG. 19 is a block diagram showing a configuration related to double density gradation processing inside the image processing processor of the image processing apparatus according to the embodiment of the present invention.

FIG. 20 is an explanatory diagram showing an edge extraction filter used in double-density gradation processing of the image processing apparatus according to the embodiment of the present invention.

FIG. 21 is an explanatory diagram showing a threshold matrix used in double density gradation processing of the image processing apparatus according to the embodiment of the present invention.

FIG. 22 is another explanatory diagram showing a threshold matrix used in the double density gradation processing of the image processing apparatus according to the embodiment of the present invention.

FIG. 23 is an explanatory diagram showing transmission data transmitted by the transmission unit of the image processing apparatus according to the embodiment of the present invention.

FIG. 24 is another explanatory diagram showing transmission data transmitted by the transmission unit of the image processing apparatus according to the embodiment of the present invention.

[Explanation of symbols]

100 image data control unit 101 image reading unit 102 image memory control unit 103 image processing unit 104 image writing unit 201 reading unit 202 sensor board unit 203 image data control unit 204 image processing processor 205 video data control unit 206 imaging Unit (engine) 210 Serial bus 211 Process controller 212,232 RAM 213,233 ROM 220 Parallel bus 221 Image memory access control unit 222 Memory module 223 Personal computer (PC) 224 Facsimile control unit 225 Public line 231 system Controller 234 Operation panel 301, 303, 304, 306 Interface (I / F) 302 Scanner image Processing unit 305 Output image processing unit (image quality processing unit) 307 Command control unit 308 Serial interface 401 Input / output port 402 Bus switch / local memory 403 Memory control unit 404 Processor array unit 405 Program RAM 406 Data RAM 408 Serial interface 501 Image data input / output control unit 502, 507 Image data input / output control unit 504 Data conversion unit 505, 508, 509 I / F 510 command control unit 601 edge smoothing processing unit 602 pulse control unit 603, 604, 701, 702 I / F 605 Data conversion unit 703 Memory access control unit 704 Line buffer 705 Video control unit 706 Data compression unit 707 Data decompression unit 708 Data conversion unit 800 Image engine control unit Doo 1701 facsimile transmission and reception unit 1801 register (Reg) 1802 multiplexer (MUX) 1803 barrel shifter (Shift Expan
d) 1804 Logical operation unit (ALU) 1805 Accumulator (A) 1806 Temporary register (F) 1901 Control unit 1902 Feature amount extraction algorithm storage unit 1903 Feature amount extraction unit 1904 Input unit 1905 Speed conversion FIFO 1906 Threshold matrix creation unit 1907 Judgment unit 1908 Threshold matrix creation algorithm storage unit 1909 Comparison unit 1910 First transmission unit 1911 Second transmission unit 1912 Output units 2001 to 2004 Filter 2101 Coefficient matrix

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5B057 AA11 BA02 BA11 CA12 CA16                       CB06 CB12 CB16 CC01 CD10                       CE05 CE13 CH04 CH05 CH14                       DC16 DC22                 5C076 AA21 BA06 BB04                 5C077 LL19 MP01 PP01 PP47 PP68                       PQ08 PQ12 PQ23 RR04 RR06                       SS02 TT02

Claims (16)

[Claims] 1. An image capable of converting a read image signal into a digitally converted image signal, or converting digitally generated image information into an image signal, and outputting the digitally converted image signal as a visible image. In an image processing apparatus equipped with a programmable arithmetic means for performing image processing so as to obtain a signal, the arithmetic means is an n-value (n-value) having a resolution of N (dpi).
> 2) input image data has a function of performing a double density binarization conversion process to binary output image data having a resolution of 2N (dpi), and the arithmetic means has a double density binarization conversion process. At the time of executing, the feature amount extraction unit that obtains the feature of the input image data as a feature amount that is a continuous amount of pixels that are equal to or greater than a predetermined threshold value and pixels that are less than the threshold value, Threshold matrix creating means for creating a threshold matrix of vertical 2 × horizontal 2 pixels for each pixel of input image data, and comparison for determining binarized densities for 4 pixels for 1 pixel of input image data based on the threshold matrix An image processing apparatus comprising: 2. The feature quantity extracting means comprises a plurality of algorithms for creating a threshold matrix having a resolution of 2N (dpi), and the algorithms can be switched by a switching instruction from the outside. The image processing apparatus according to claim 1. 3. The feature amount extraction means performs, as the algorithm, four filter operations that are different for each direction with the image data as a target pixel in order to extract the edge degree of the input image data, and an absolute value is obtained. The image processing apparatus according to claim 2, wherein the largest calculation result is determined as the feature amount for the pixel. 4. The feature amount extraction means, as the algorithm, compares a given threshold value and pixel density with respect to received image data for one line,
The image processing apparatus according to claim 2, wherein a continuous amount of pixels equal to or larger than a threshold value and pixels smaller than the threshold value is determined as a feature amount. 5. The plurality of transmitting means for externally transmitting binary image data having a resolution of 2N (dpi) in different transmission formats, and the transmitting means capable of transmitting with the smallest data amount based on the characteristic amount. The image processing apparatus according to claim 1, further comprising: a determining unit that selects a unit and outputs it to the outside. 6. One of the plurality of transmitting means represents a continuous amount of white pixels and black pixels in the binary image data by a predetermined number of bits, and the predetermined amount is used to determine the continuous amount of white pixels. Alternatively, the image processing apparatus according to claim 5, wherein a black pixel is designated and transmitted. 7. The method according to claim 5, wherein one of the plurality of transmitting means packs and transmits binary image data of pixels corresponding to the same number of bits in a data string having a predetermined number of bits. Image processing device. 8. An image capable of converting a read image signal into a digitally converted image signal, or converting digitally generated image information into an image signal, and outputting the digitally converted image signal as a visible image. In an image processing method for processing an image into a signal, an n-value (n> 2) input image data having a resolution of N (dpi) is doubled to a binary output image data having a resolution of 2N (dpi). When performing the density binarization conversion process, a feature amount extracting step of obtaining a feature amount of a continuous amount of pixels having a threshold value or more and a pixel having a threshold value or less as a feature amount of the input image data; A threshold matrix creating step of creating a threshold matrix of vertical 2 × horizontal 2 pixels per pixel of the input image data with a resolution of (dpi); An image processing method, comprising: a comparison step of determining binarized densities of four pixels with respect to one pixel. 9. The feature extraction step comprises a plurality of algorithms for creating a threshold matrix having a resolution of 2N (dpi), and the algorithms can be switched based on a switching instruction. 8. The image processing method according to item 8. 10. The algorithm of the feature amount extracting step performs four filter operations which are different for each direction with the image data as a target pixel in order to extract the edge degree of the input image data, and the absolute value is the most significant. The image processing method according to claim 9, wherein a large calculation result is determined as a feature amount for the pixel. 11. The algorithm of the feature amount extracting step compares a given threshold value and a pixel density with respect to the received image data for one line, and obtains a continuous amount of pixels equal to or more than the threshold value and pixels less than the threshold value. The image processing method according to claim 9, wherein the image processing method is determined to be a feature amount. 12. One of a plurality of transmission formats capable of transmitting binary image data having a resolution of 2N (dpi) after the double-density binarization conversion processing with the smallest data amount based on the feature amount. 9. The image processing method according to claim 8, further comprising an output step for selecting and outputting to. 13. The transmission format of the output step expresses a continuous amount of white pixels and black pixels in binary image data by a predetermined number of bits, and the predetermined amount is used to determine the continuous amount of white or black pixels. 13. The image processing method according to claim 12, wherein the image is designated and transmitted. 14. The image processing according to claim 12, wherein the transmission format of the output step is to pack and transmit binary image data of pixels corresponding to the same number of bits in a data string of a predetermined number of bits. Method. 15. A program for causing a computer to execute the method according to any one of claims 8 to 14. 16. A computer-readable recording medium on which the program according to claim 15 is recorded.