KR930006801B1 - System for recording an image having a facial image and id information - Google Patents

Abstract

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Description

A system for recording a face image and an image with ID information

1 is a system block diagram of an embodiment of the present invention.

2 shows the layout of each area on the application of FIG.

3 is a diagram showing the configuration of the image reading unit of FIG.

4 is a block diagram showing the configuration of the input image processing unit shown in FIG.

5 is a block diagram showing the configuration of the edge detection circuit of FIG.

6 is a block diagram showing the configuration of the mark detection circuit of FIG.

FIG. 7 is a block diagram showing the structure of a line density conversion circuit as one of FIG.

8 is a view for explaining the principle of the linear density conversion circuit of FIG.

9 is a block diagram showing the configuration of the black and white processing circuit of FIG.

10 is a block diagram showing the configuration of the concentration detection circuit of FIG.

11 is a timing chart of each part of the concentration detection circuit of FIG.

12 shows concentration histograms obtained from the concentration detection circuit.

FIG. 13 is a block diagram showing the configuration of the color judgment circuit of FIG.

FIG. 14 is a block diagram showing the configuration of the output image processing section shown in FIG.

FIG. 15 is a block diagram showing the structure of the concentration correction circuit of FIG.

FIG. 16 is a diagram schematically showing the configuration of the printing unit of FIG.

* Explanation of symbols for main parts of the drawings

100 Application 101: Subject Fisherman

102: keyboard 103: display unit

104: image reading unit 105: character recognition unit

106: input image processing unit 107: image processing control unit

108: output image processing unit 109: printing unit

110: mass storage unit 111: image input unit

112: image interface 113: communication interface

114: communication circuit 115: host computer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording system, and in particular to an image recording system having a face image and ID information used for producing printed matters, such as an ID card or booklet, such as a driver's license, an identity card, a passbook or a bank account.

Recording (printing) of face images and images with ID information is used for driver's licenses, identity cards, pass cards, bank accounts and other certificates.

In general, such a certificate is accompanied by a face-covered face covered with a transparent seal, and the name, date of birth, sex, issue date and issue number of the holder are printed as ID information.

Conventionally, such a certificate is made in the following order, taking a driver's license as an example.

First, the applicant fills out the necessary information on the prescribed form and fills out the application form with face photo and submits it to the counter of the management center. The center that receives this application will type the name, date of birth, sex, issue date and issue number on the form of the certificate. Next, a photograph of the face taken separately is attached on this sheet. Finally, the transparent sealant is adhered on the attached photograph and coated. This series of certificate creation work is inefficient because it is performed as a separate process. The center where computerization is in progress requires several hours from receipt of application to issue of certificate.

In the prior art, the photograph attached to the certificate and the photograph attached to the application are often different, and several photographs must be prepared.

On the other hand, in the improved driver's license issuance and renewal system, the photographing field (name, date of birth, gender, issue date, issue number, etc., written in a predetermined layout) and the applicant's face image are optically printed on the silver-printed film. Synthesize by Subsequently, the photo paper obtained by developing the film is cut into a suitable size, and then laminator is processed to complete the driver's license.

On the other hand, Japanese Patent Laid-Open No. Hei 1-20609 discloses an IC card making system for electronically synthesizing and laying out ID information on an image signal obtained by photographing an applicant's face with a TV camera and printing the processing result. In this known system, there is a face photographing process of the applicant during a series of license issuance operations. For this reason, the time required for issuance cannot be shortened sufficiently due to the shooting time and waiting time.

You also need space for face shots and space to wait for your turn. Face shooting is often allowed only once, in terms of efficiency and expense. As a result, the face image of the applicant's own unfavorable face may be recorded on the license. In such cases, the applicant feels mental distress during the validity of the license for several years.

SUMMARY OF THE INVENTION An object of the present invention is to provide a system for recording an image having a face image and ID information suitable for issuing a certificate such as a driver's license with good efficiency based on face images and ID information of an original or the like.

According to one aspect of the present invention, a manuscript of a predetermined manuscript form is prepared having an area of a face image and a region of a monochrome image constituting a part of ID information and an area of a text image constituting another part of the ID information. The image on this original is read by an image reading unit, and image signals of respective areas are output. In this image reading section, the image signals of each area are input to the processing section and processed to suit the recording style. The processed image signal is sent to a recording unit, where a face image, a monochrome image and a text image are recorded.

According to another aspect of the present invention, an original is provided with an area of a partial image of a face image and a monochrome image constituting a part of ID information and a character image constituting another part of ID information.

On the other hand, an image input unit for inputting image signals of the above-mentioned face image, the above-mentioned monochrome image, and some other images of the above-mentioned text image is provided, and image signals from the image reading unit and the image input unit are input to the processing unit. It shall be processed to conform to the record form.

For example, in the case of preparing a certificate such as a driver's license, the applicant's application is accompanied by a color or monochrome photograph of the applicant's face, which is signed by the applicant, and used as ID information other than signature. For example, the address, name, date of birth, and sex are handwritten or printed. The images on this application can be read collectively. The obtained image signal is divided into every area and then processed.

Image processing is performed in accordance with a recording style of a certificate issued for an image signal of each area, for example, the layout and size of each area. The processed image signal is sent to a printing unit which is a recording unit, and a certificate is printed and issued. Apart from the image signal obtained by reading the image on the application form, for example, when an image signal obtained by reading an image recorded on various recording media is input, such image signal is processed in the same manner.

In this way, the process of photographing a face image is unnecessary after the application is submitted, and all the information to be printed on the certificate is processed simultaneously, thereby greatly reducing the time required for issuance of the certificate. The face image printed on the certificate can be selected by the applicant himself.

FIG. 1 shows a system for processing an image signal obtained by reading an image on the application 100 to create and issue a certificate 200 such as a driver's license. This system comprises a main control unit 101, a keyboard 102, a display unit 103, an image reading unit 104, a character recognition unit 105, an input image processing unit 106, and an image processing control unit 107 constructed using a CPU. ), An output image processing unit 108, a printing unit 109, a mass storage unit 110, an image input unit 111, an image interface (IF) 112, and a communication interface 113.

The communication interface 113 is connected to the host computer 115 of the center by, for example, the communication circuit 114. In addition, the thick line of FIG. 1 shows a data line of a bit, and a thin line shows a control line.

The application form 100 includes a photograph area (face image area) 201 for attaching a color photograph or a monochrome photograph of the applicant's face image as shown in FIG. 2, and a signature area (mono image area) for the applicant to sign. 202), and the applicant has three types of image areas: a character area (character image area) 203 for writing letters which are ID information other than a signature as letters such as handwriting or type.

The reference line 204 is provided in the signature area 202. On the left end edge shown in the drawing of the application form 100, reference marks 205 and 206 for giving reference coordinates for detecting the edges described later are printed. The mark 205 indicates a reference coordinate for edge detection of the photo area 201, and the mart 206 indicates a reference coordinate for edge detection of the signature area 202. At the upper edge shown in the drawing of the application form 100, a mark 207 and a mark 208 with or without defects are formed by the presence or absence of printing for identifying the form of the application form. In the example of FIG. 2, the marks 207 and 208 each have three unit mark areas, so that each of the eight types of applications can be represented as a digital code.

A plurality of forms are prepared in advance for the application 100. These forms differ in the layout of each of the areas 201, 202 and 203 depending on the purpose of the application (new issue, reissue, correction, addition, cancellation of registration, urgent issue, etc.).

The application form used by the applicant may be wrong, or the index print (the object of the dropout color processing in the character area 203) indicating the character border or the like may be changed in each form so that there is no procedure error in the window work. The application 100 is selected from among these types of forms according to the application purpose. The application 100 may be processed by the application contents and may be processed at random. In any form of processing, it is possible to flexibly respond by identifying the style of the application 100. The identification of the form of the application form 100 is automatically performed by inputting an instruction by the operator's keyboard 102 or by reading the aforementioned marks 207 and 208 provided on the application form 100. The former is valid if an application of the same form has been filed to some extent. The latter type of identification is valid if there are multiple applications.

In this embodiment, automatic identification is used. The schematic operation of the system of FIG. 1 will be described.

Application (100) shown in FIG. 2 made by applicant is submitted to window of management center. The submitted application 100 is set in the image reading unit 104. The form of the set application 100 is identified by an application identifier to be described later, which is installed in the image reading unit 104 to generate an application identification code, and is sent to the main control unit 101. The determination of which application identification code is determined in the form of the identified application is made at the discretion of the system design. Thereafter, the image on the application form 100 is read by the image reading unit 104, and an image signal is output. This image signal is input to the input image processing unit 106. The input image processing unit 106 divides the input color image signal into respective regions 201, 202, and 203 of FIG. 2 by control from the image processing control unit 107, and then applies the image signal of each region. The predetermined process is performed.

The processing result of the input image processing unit 106 is transmitted to the main control unit 101 via the image processing control unit 107. The main control unit 101 transmits the image data to the character recognition unit 105 in the character area 203 of FIG. 2 of the processing results from the input image processing unit 106. FIG. The character recognition unit 105 performs character recognition by two-step processing by a known compound similarity method and a feature structure matching method, and transmits the recognition result to the main control unit 101 as character code data. The main control unit 101 displays the character image designated by the character code data from the character recognition unit 105 and the face photograph image and signature image of the face photograph area 201 and the signature area 202 of FIG. 103).

The operator compares and displays the display contents of the display section 103 with the contents of the application form 100 to confirm the suitability. If the display content of the text image is different from the content on the text area 203 of the application 100, the operator may determine whether there is a read / write error in the image reading unit 104 or a recognition error in the text recognition unit 105. To judge. In that case, the operator makes corrections using the keyboard 102 or reads again in the image reading unit 104 to input a command of the main point. When the certificate 200 is issued by re-issuance, renewal, or the like, the host computer 115 and the mass storage unit 110 as a database, in addition to the face photograph image and the signature image of the face photograph area 201 and the signature area 202, are provided. The registered contents are displayed on the display unit 103. The operator confirms the contents of the application from this display and makes appropriate changes. At this time, the operator communicates with the host computer 115 online through the main control unit 101 as necessary, and performs various verification operations including a credit check and the like and receives the issue number.

After that, the operator inputs the work classification such as new issue, reissue, correction, addition, registration cancellation, emergency issue, etc. to the main control unit 101 through the keyboard 102 and delivers the work classification to the host computer 115. Receive the necessary commands to continue. In the case of an unregistration, the job ends here. The image data confirmed and corrected in this way is once transmitted from the main control unit 101 to the large-capacity storage unit 110, accumulated, and then transferred to the output image processing unit 108 via the image processing control unit 107.

Here, a preset recording format is set for the image data accumulated in the large-capacity storage unit 110 corresponding to the work classification recognized in the application identification code described above.

In the output image processing unit 108, the recording form in the certificate 200 and the characteristics of the printing unit 109 for the image data transmitted from the mass storage unit 110 through the main control unit 101 and the image processing control unit 107. Process to get a match. Image data transmitted from the main control unit 101 to the large-capacity storage unit 110 may also be transmitted to the output image processing unit 108 in parallel. The printing unit 109 receives the processing result of the output image processing unit 108 and prints out the applicant's face image and ID information on a predetermined sheet of paper to create a certificate 200. The written certificate 200 is transferred to the applicant. Subsequently, each part of FIG. 1 is explained in full detail.

3 shows the configuration of the image reading unit 104. The image reading unit 104 reads the images of the respective areas 202 and 203 on the application form 100 as one scan, and also applies to the applicant's face photograph on the photo area 201 where the highest resolution is required. It is configured to have sufficient read resolution and to read color photographs as well as monochrome photographs. In FIG. 3, the application form 100 is conveyed by the conveyance mechanism 301 at a constant speed in the arrow Y direction (sub-scan direction). This conveyance operation corresponds to a subscan. The surface of the application form 100 is illuminated by the light source 303 driven by the light source driving circuit 302, and the image on the surface is formed on the color image pickup element 305 by the imaging lens 304. The image on the application 100 is read by the color image pickup device 305 as a density of, for example, 16 dots / mm.

The color image pickup device 305 includes three CCD line image sensors 306 including an array of photoelectric conversion elements serving as color filters of R (red), G (green), and B (blue), and a transfer CCD (charge coupled device). R) 306G and 306B. The photoelectric conversion element arrays of each of the line image sensors 306R, 306G, and 306B are arranged in a line shape in the vertical direction (main scanning direction) with respect to the page of the drawing.

As the color image pickup device 305, a CCD color image sensor in which three color filters of R, G, and B are formed in a sequential order may be used. The color image pickup device 305 is driven by the CCD driving circuit 307 and decomposed into components of R, G, and B according to an image formed by electrical scanning (scanning) in the arrangement direction of the photoelectric conversion element array. An electrical signal, i.e., an RGB color image signal in line order, is output. This color image signal is converted into a digital signal of, for example, about 8 bits by the A / D converter 309 and input to the image correction circuit 310. The image correction circuit 310 is composed of an SHD (shading) correction circuit 311, a space correction circuit 312, and a rearrangement circuit 313.

The SHD correction circuit 311 includes an illumination stain on the application 100 and an imaging lens 304 by the light source 303. The SHD correction circuit 311 includes an image signal for the light spot stain of the imaging optical system and the sensitivity stain of the color image pickup device 305. Level correction and standardization are performed. The space correction circuit 312 corrects the spatial shift in the main scanning direction of the CCD line image sensors 306R (306G) and 306B.

The rearrangement circuit 313 converts the above line-order RGB color image signal into a point-sequential RGB color image signal. Since the configuration of the correction circuits 311, 312 and 313 is well known facts, detailed description thereof will be omitted here. The configuration of the image correction circuit 310 is appropriately changed in accordance with the configuration of the color image pickup device 305. Application identifier 314 reads marks 207 and 208 of FIG. 2 to identify the form of application 100. The application identifier 314 is formed by, for example, six non-contact optical sensors installed in correspondence with a total of six unit mark areas of a mark 207 and a mart 208, and an electronic circuit for logically processing such sensor output. It is composed.

Each sensor detects the state of each unit mark area (with or without printing) by using the difference between the amount of reflected light in the background and the mark portion, and generates a logic level signal according to the state of the unit mark area.

An application identification code is generated by performing logical processing (basic logic) as the above electronic circuits on the output signals of the three sensors corresponding to the mark 207 and the output signals of the three sensors corresponding to the mark 208. This application identification code is supplied to the main control part 101 of FIG. Combining the marks 207 and 208 can increase the number of identifiable application forms. If at least the number of identifiable forms is good, only one of the marks 207 and 208 may be used.

The timing generator 315 is operated by a basic clock supplied from the clock generator 316 under the control of the main controller 101 of FIG. 1 to operate the light source driver circuit 302, the CCD driver circuit 307, and the A / D converter ( 309, various timing signals required for the image correction circuit 310 and the application identifier 314 are generated.

In this way, the image reading unit 104 reads an image of the entire area required for the application 100 at a density of 16 dots / mm as one-time image reading operation consisting of the main and sub-scans, and the number of gradations is 2 ^8. A point-sequential RGB color image signal of = 256 is output.

This color image signal is supplied to the input image processing unit 106 of FIG. The input image processing unit 106 enters the color image signal inputting processing until confirmation and correction of the above-described operator, assignment of issuance permission from the host computer 115, and designation of various management numbers such as issuance numbers. It is performed.

The input image processing unit 106 includes an edge detection circuit 401, an area division circuit 402, a linear density conversion circuit 403, 404, 405, a monochromating processing circuit 406, and density as shown in FIG. The detection circuit 407, the color determination circuit 408, the dropout color processing circuit 409, the quantization circuit 410, and the buffer memory 411 are configured.

The edge detection circuit 401 detects a range (border) of each area required for the area division as the area division circuit 402 and generates an edge signal. The area dividing circuit 402 divides the image signals of the areas 201, 202 and 203 of the application form 100 and transmits them on different signal lines in accordance with the edge signal. The area dividing circuit 402 can be realized as an exchange circuit for exchanging an edge signal as a control input.

5 shows the configuration of the edge detection circuit 401. As shown in FIG.

The edge detection circuit 401 is inputted with the RGB image signals in the point sequence from the image reading unit 104 and synchronized with the pixel data of the RGB image signals via the image processing control unit 107 in the main control unit 101. The synchronization signals HSYNC and PSYNC synchronized with one pixel clock GCLK, the main scan and the sub-scan of the image reading unit 104, respectively, and the application identification code described above are input.

The synchronization signal PSYNC is generated based on the tip detection signal of the application 100 generated by the application sensor (not shown) provided in the image reading unit 104, and is used as the processing start signal of the input image processing unit 106.

The XY reference counter 501 counts the X counter for obtaining the coordinate value in the main scanning direction by counting the main scan synchronizing signal HSYNC as the counter start signal, and counting the main scan synchronizing signal HSYNC as the counter start signal. It is configured as a Y counter for obtaining coordinate values in the sub-scanning direction and generates coordinate values corresponding to respective pixel data of the input RGB image signal. The data of the coordinate values of each of X and Y is represented as, for example, digital data of 12 bits.

The mark extracting edge generating circuit 502 detects the form of the application by the application identification code, and outputs an edge signal for extracting a signal from the reference marks 205 and 206 of FIG. 2 corresponding to the form. It is sequentially generated in accordance with the coordinate value from 501, and is supplied to the trimming gate circuit 503 as a gate signal.

The mark extraction edge generating circuit 502 is constituted by a PLD (programmable logic device, for example, GAL 16 V8 manufactured by Lattice, Inc.) or a ROM (reading memory). Corresponding to various forms of the application form 100, a preset mark extraction frame is programmed in the PLD or written in the ROM. The position and size of the mark extraction frame include the accuracy of the position reading of the image reading unit 104, in particular, skew and the like, and sufficiently adds the conveying precision of the conveying mechanism 301 to the marks 205 and 206 inside the frame. Only it is set to be surely included.

Specifically, the size of the mark extraction frame is, for example, approximately 8 mm as the actual size on the application 100, which corresponds to 128 dots x 128 dots of the color image signal output from the image reading unit 104. The trimming gate circuit 503 is provided with such a mark extraction edge signal as a gate signal to gate and extract the RGB image signal. The gated RGB image signal is converted into a monochrome image signal by the monochromeization processing circuit 504. The monochrome image signal is averaged by, for example, a matrix of 2x2 in the averaging circuit 505, so that noise and isolation components are removed and then converted into a two-value signal using a predetermined upper limit in the binarization circuit 506. Therefore, it is input to the mark detection circuit 507. The mark detection circuit 507 determines the coordinate values of the marks 205 and 206 from the input two-value signal, and supplies them to the latch / comparator 508 using the coordinate values as reference coordinate values.

The latch / comparator 508 latches the reference coordinate value, compares it with the coordinate values sequentially updated in the XY reference counter 501, and supplies a start signal to the XY frame counter 509 when both match. The XY frame counter 509 counters the pixel clock GCLK and the main scan synchronization signal HSYNC at the time when the start signal is input. That is, the XY frame counter 509 outputs the read coordinate value based on the reference coordinate value. The read coordinate values from the XY frame counter 509 are input to the signature border generating circuit 511 and the photo border generating circuit 512.

The signature border generating circuit 511 and the photo border generating circuit 512 identify the style of the application 100 by the application identification code, respectively, and the signature border signal and the photo border signal corresponding to the style are XY frame counters 509. Generated in order according to the reading coordinate value from).

The signature border generation circuit 511 and the photo border generation circuit 512 are configured by, for example, a PLD or a ROM. Corresponding to the various forms of the application form 100, the data of the signature area 202 and the border (signature border and picture border) of the picture area 201 having different positions and sizes are pre-programmed in the PLD or ROM. It is written.

The handwritten character border generating circuit 513 basically regards the portion of the application 100 except for the area surrounded by the signature border and the photo border as the character area 203, and the handwritten character border indicating the border of the area. Occurs as a signal. The handwritten character edge generating circuit 513 is similarly configured as a PLD or ROM, and each form of the application 100 is different, and data of the edges of all areas is programmed or stored in advance.

The program or written data is read by the application identification code and generates data of the edge of an area other than the area enclosed by the signature border and the picture border as a character border signal. For this reason, the edge signals from the signature edge generation circuit 511 and the photo edge generation circuit 512 are applied to the handwritten character edge generation circuit 513. The edge signals from the signature edge generation circuit 511, the photo edge generation circuit 512, and the handwritten character edge generation circuit 513 are input to the decoder 514, and two bits for distinguishing these three types of areas are provided. Convert to code signal.

Since the RGB image signal from the image reading unit 104 is a time series signal, image signals of two or more regions are not included at the same time. Therefore, the code signal output from the decoder 514 may indicate which area the RGB image signal of the pixel input at that time belongs to. In this manner, the edge detection circuit 401 combines trimming using a fixed mark extraction edge set as the mark extraction edge generation circuit 502 and detection of the reference marks 205 and 206 from the trimmed RGB image signal. The reference coordinate values for generating edge signals of the areas 201, 202, and 203 are obtained.

Prior to mark detection, the averaging circuit 505 performs noise and isolation point removal processing. Such processing has an advantage that mark detection that is strong against interference such as skew, noise, and influence of contamination of the application 100 when the image reading unit 104 reads the image on the application 100 is performed. The edge signal output from the edge detection circuit 401 is supplied to the image processing controller 107 in addition to the area division circuit 402 in FIG.

The mark detection circuit 507 in FIG. 5 is configured as shown, for example, in FIG. The two-value signal from the binarization circuit 505 is serially input to the 512-bit shift register 600 constructed by cascading eight 64-bit shift registers 601-608. The output of each final stage of the 64-bit shift registers 601-608 is input to the AND circuit 609 and the output of the AND circuit 609 is serially input to the 8-bit shift register 610. The 8-bit output of 610 is input to the parallel AND circuit 611.

When the final stage output of all 64-bit shift registers 601-608 becomes "H", the output of the AND circuit 609 becomes "H". If the output of the AND circuit 609 continues eight times in a state of " H " level, the output of the mode bits of the 8-bit shift register 610 becomes " H " simultaneously, so that the output of the AND circuit 611 is " H " ", And a detection signal is output. That is, the mark detection circuit 507 has a window of 8 dots x 8 dots of the input two-value signal. Since the input signal of the mark detection circuit 507 is a signal obtained by binarizing a monochrome image signal (luminance signal) having a dot density of 8 dots / mm by averaging 2x2 in the averaging circuit 505, The window is 1 mm square at the actual size on the application 100. If all of the two-value signals in this window are high level, that is, "H" (black level), the mark detection signal is outputted because the reference mark 205 or 206 is in the window.

Referring back to FIG. 4, the image signals of the regions 201, 202 and 203 from the region dividing circuit 402 are transferred to the respective regions by the line density conversion circuits 403, 404 and 405. A linear density conversion, that is, scaling, is performed at an appropriate conversion factor.

The conversion magnification for the image signal of the picture area 201 and the signature area 202 is determined by the size of the areas 201 and 202 on the application form 100, the read dot density of the image reading unit 104 (16 dots / Mm) and the recording style (size of each area, etc.) on the certificate 200. The conversion magnification for the image signal in the character area 203 is determined by the read dot density required by the character recognition part 105. A plurality of conversion magnifications are required to correspond to the plurality of recording styles.

The character recognition unit 105 is the same size as the image recording density of the printing unit 109 is 12 dots / mm, the photograph area 201 on the application form 100 and the corresponding area on the signature area 203 and the certificate 200. The read dot density required at is 8 dots / mm. In this case, the conversion ratio of the image signal of the picture area 201 and the signature area 202 is 12/16 = 3/4, and the conversion ratio of the image signal of the character area 203 is 8/16 = 1/2. do.

Simultaneous realization of such two or more conversion magnifications in a real time process is difficult for general linear density conversion processing performed in combination with mechanical sub-scanning.

For this reason, in the present embodiment, as described later, line density conversion is performed as an electronic process by the line density conversion circuits 403, 404 and 405 in either the main scanning direction or the sub scanning direction.

FIG. 7 is a diagram showing the configuration of a linear density conversion circuit for performing two-dimensional conversion in such a main scanning direction and a sub-scanning direction. The selector 701, two line memories 702, 703, a memory control section 704, Latch 705, 706, coefficient control unit 707, coefficient multiplier 708, 709, 714, 715, buffer 710, adder 711, 716 and two three-stage latches 712 713.

The coefficient multipliers 708, 709, 714, and 715 are each constituted by a coefficient ROM storing coefficient data and a multiplier that multiplies a coefficient by an input signal. The principle of the linear density converting circuit will be described with reference to FIG. The original image signal input to the linear density conversion circuit is X, and the sample interval Px is 1. When the density in the main scanning direction of the original image signal X is 0.75 times, it is conceivable to set the sample interval Py of the density-converted image signal Y to 0.75 Px.

It is assumed that the j-th (j≥0) pixel of the linear density-converted image signal Y represents information at the position 0.75j of the original image signal X. The position is 0.75j or less, and the values (i + 1-0.75j) and (0.75ji) of the sample (Xi) of the original image signal closest to 0.75j and the value of the signal (Xi + 1) on the right are respectively The result of multiplying and multiplying the coefficients is set to the value Yj of the j-th pixel of the linearly-converted image signal Y.

For example, in Fig. 8, the value Y0 of the zero pixel of the linearly-converted image signal is the same as the value of the first pixel of the original image signal. The value Y1 of the first density of the linearly-converted image signal is obtained by adding 0.25 times the value X0 of the zeroth pixel of the original image signal and 0.75 times of the fresh X1 of the first pixel.

This same ending also generalizes the operation of the conversion process.

Yj = (1-a) Xi + aXi + 1

a = frac (j / R)

Becomes

Where frac is the fractional part of the value of (j / R), and R is the magnification of the linear density conversion.

In the above principle explanation, the linear density conversion in the main scanning direction has been described, but the linear density conversion in the sub scanning direction can be performed on the same principle.

7 shows the linear density conversion circuit based on this principle.

The input image signals are supplied to the line memories 702 and 703 one by one in the main scanning direction by the selector 701 and are written to the line memories 702 and 703 by the control from the memory control section 704. . The pixel control unit GCLK is assigned to the memory control unit 704 via the image processing control unit 107 in the main control unit 101. Image signals read out one line from the line memories 702 and 703 by the control from the memory control unit 704 are inputted to the coefficient multipliers 708 and 709 through the latches 705 and 706, respectively, and counted. Is multiplied.

The image signals superimposed by the coefficient multipliers 708 and 709 are added by the adder 711 to perform linear density conversion in the sub-scanning direction. The output of the latch 705 is input to the first three stage latch 712 through the buffer 710 and the output of the adder 711 is applied to the second three stage latch 713. The output of either one of the buffer 710 or the adder 711 is input to the coefficient multiplier 714, and the output of either one of the three-stage latches 712 and 713 is input to the coefficient multiplier 715.

By coefficient multipliers 714 and 715

Claims (1)

No content.