JP2008227710A - Unit, method and program for image processing, and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify hardware for processing image data by simultaneously reading both surfaces of a manuscript. <P>SOLUTION: An image processing unit includes: readout means 11, 12 for simultaneously reading both surfaces of the manuscript; pixel rate conversion means 13, 14 for converting the pixel rates of the read front surface image data and the back surface image data into the same pixel rate; image shift means 16, 17 for adjusting deviation between a main scanning direction and a sub-scanning direction of the front surface image data and the back surface image data from the pixel rate conversion means 13, 14; an image composition means 18 for combining the front surface image data with the back surface image data from the image shift means 16, 17 on the same line; and an image processing means 19 for applying the same image processing to the front surface image data and the back surface image data combined in the image composition means 18. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image processing apparatus, an image processing method, an image processing program, and a recording medium that process image data on the front and back surfaces of a document that are simultaneously read by a reading unit.

  In scanner devices, copiers, fax machines, digital copiers, etc., in order to improve the operability when reading double-sided originals and to shorten the reading time, reading devices are provided on both the front and back sides of the originals. An image processing apparatus has been developed that simultaneously reads the front and back surfaces. A related technique will be disclosed next.

  In Patent Document 1, a plurality of image data is written to the primary memory in a time-sharing manner, and each of the plurality of written image data is sequentially read out from the primary memory, thereby connecting to the parallel bus connected to the transfer destination. There has been proposed a technique that makes it possible to transfer data by one channel with a single mouth.

Patent Document 2 proposes a technique for reducing the size and cost of an apparatus that acquires shading data for front and back surfaces in so-called double-sided simultaneous reading that can read images formed on both front and back surfaces of a document. .
JP 2002-109527 A JP 2006-80941 A

  In the case of having reading means for reading the front and back surfaces of the document, it is necessary to separately provide hardware corresponding to each reading means. This is because it is necessary to individually perform image processing on the two types of image data including the front surface image data and the back surface image data. Therefore, in such a structure, there is a problem that hardware increases. In addition, there is a problem that the control is complicated because it is necessary to operate the hardware in accordance with the front and back.

  The present invention has been made in consideration of such conventional problems, and it is possible to simplify the control without increasing hardware when performing image processing by simultaneously reading the front and back surfaces of a document. An object of the present invention is to provide an image processing apparatus, an image processing method, an image processing program, and a recording medium.

  The image processing apparatus according to claim 1 is a reading unit that simultaneously reads the front and back surfaces of a document, a pixel rate conversion unit that converts the pixel rates of the read front surface image data and back surface image data to the same pixel rate, The image shift means for adjusting the deviation in the main scanning direction and the sub scanning direction of the front surface image data and the back surface image data from the pixel rate conversion means, and the front surface image data and the back surface image data from the image shift means are combined on the same line. And image processing means for performing the same image processing on the front surface image data and the back surface image data combined by the image combining means.

  A second aspect of the present invention is the image processing apparatus according to the first aspect, wherein the pixel rate converting means detects a slow pixel rate from the read pixel rate of the front surface image data and the read pixel rate of the back surface image data. A rate detection unit, and a pixel clock generation unit that generates a pixel rate clock that is an integral multiple of the slower pixel rate detected by the pixel rate detection unit and converts the front surface image data and the back surface image data to the same pixel rate. It is characterized by.

  A third aspect of the present invention is the image processing apparatus according to the first aspect, wherein the image shift means moves a relative position of the line gate signal indicating the effective image area of the main scanning with respect to the image data in the main scanning direction. A line gate shift means and a frame gate shift means for moving a relative position of the frame gate signal indicating the effective image area of the sub scan with respect to the image data in the sub scan direction. The image data and the back image data are controlled independently.

  A fourth aspect of the present invention is the image processing apparatus according to the first aspect, wherein the image synthesizing unit arranges the surface image data converted and input by the pixel rate converting unit in the first half of one line. The output is performed so that the back surface image data is arranged in the second half of one line, and these are combined on a single line.

  The invention according to claim 5 is the image processing apparatus according to claim 4, wherein the image synthesizing means is provided between the front surface image data arranged in the first half of one line and the back surface image data arranged in the second half. The present invention is characterized by generating invalid image area width and invalid area data.

  A sixth aspect of the present invention is the image processing apparatus according to the first aspect, wherein the image processing unit performs a common process on the front surface image data and the back surface image data combined by the image combining unit. It is characterized by that.

  The invention according to claim 7 is the image processing apparatus according to claim 1, wherein the image processing means includes the front surface image data arranged in the first half of one line and the back surface image data arranged in the second half by the image composition means. The image processing is performed by switching processing parameters in the first half and the second half of one line.

  An image processing method according to an eighth aspect of the present invention includes a reading step of simultaneously reading the front surface and the back surface of a document, a pixel rate conversion step of converting the pixel rates of the read front surface image data and back surface image data to the same pixel rate, The image shift step for adjusting the deviation in the main scanning direction and the sub scanning direction of the front surface image data and the back surface image data from the pixel rate conversion step, and the front surface image data and the back surface image data from the image shift step are combined on the same line. And an image processing step for performing the same image processing on the front surface image data and the back surface image data combined in the image combining step.

  A ninth aspect of the present invention is the image processing method according to the eighth aspect, wherein the pixel rate conversion step detects a slow pixel rate from the read pixel rate of the front surface image data and the read pixel rate of the back surface image data. A rate detection step, and a pixel clock generation step of generating a pixel rate clock that is an integral multiple of the slower pixel rate detected by the pixel rate detection means, and converting the front surface image data and the back surface image data to the same pixel rate. It is characterized by.

  According to a tenth aspect of the present invention, in the image processing method according to the eighth aspect, the image shift step moves a relative position of the line gate signal indicating the effective image area of the main scanning with respect to the image data in the main scanning direction. A line gate shift step, and a frame gate shift step for moving a relative position of the frame gate signal indicating the effective image area of the sub scan with respect to the image data in the sub scan direction, the line gate shift step and the frame gate shift step being a surface The image data and the back image data are controlled independently.

  The invention according to claim 11 is the image processing method according to claim 8, wherein the image composition step arranges the surface image data converted and input by the pixel rate conversion step in the first half of one line. In this step, the back image data is output so as to be arranged in the second half of one line, and these are combined on a single line.

  The invention according to claim 12 is the image processing method according to claim 11, wherein the image composition step is performed between the front surface image data arranged in the first half of one line and the back surface image data arranged in the second half. This is a step of generating invalid image area width and invalid area data.

  A thirteenth aspect of the present invention is the image processing method according to the eighth aspect, wherein the image processing step performs a common process on the front surface image data and the back surface image data combined in the image combining step. It is a step.

  The invention according to claim 14 is the image processing method according to claim 8, wherein the image processing step includes front surface image data arranged in the first half of one line and back image data arranged in the second half in the image synthesizing step. Is a step of performing image processing by switching processing parameters in the first half and second half of one line.

  An image processing program according to a fifteenth aspect of the invention is a program for causing a computer to execute the steps according to any one of the eighth to fourteenth aspects.

  A recording medium according to a sixteenth aspect of the invention is a computer-readable recording medium on which the image processing program according to the fourteenth aspect is recorded.

  According to the present invention, the pixel rate conversion means converts the image data on the front and back surfaces to the same pixel rate, the image shift means adjusts the deviation of the image data on the front and back surfaces in the main scanning direction and the sub-scanning direction, and the image composition means However, since the image data on the front and back surfaces are combined on the same line, hardware for individually processing the two systems of image data on the front and back surfaces is not required, the hardware can be simplified, and control is facilitated.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments. FIG. 1 is a block diagram of an image processing apparatus according to an embodiment of the present invention.

  In FIG. 1, a first reading unit 11 and a second reading unit 12 generate image data by scanning a document. For example, the first reading unit 11 reads the front side of the document to generate front surface image data, and the second reading unit 12 reads the back side of the document to generate back side image data. These reading means 11 and 12 have clock generators 11a and 12a, respectively.

  Pixel rate conversion means 13 and 14 are connected to the first reading means 11 and the second reading means 12, respectively. A clock from the clock generator 15 is input to these pixel rate conversion means 13 and 14. The clock generator 15 generates a common clock. The image data read by the first reading unit 11 is input to the first pixel rate conversion unit 13, and the image data read by the second reading unit 12 is input to the second pixel rate conversion unit 14.

  The first pixel rate conversion unit 11 uses the pixel rate of the image data (surface image data) from the first reading unit 11 as the first image shift unit in the subsequent stage at the pixel rate generated by the clock generator 15 that is a common clock generation unit. 16 to send. The second pixel rate conversion unit 14 transmits the pixel rate of the image data (back surface image data) from the second reading unit 12 to the second image shift unit 17 at the subsequent stage at the pixel rate generated by the clock generator 15. Here, the pixel rate of the image data output from the first pixel rate conversion unit 13 and the pixel rate of the image data output from the second pixel rate conversion unit 14 are the same pixel rate.

  Next, the first image shift unit 16 finely adjusts the mechanical electric shift in the main scanning direction and the sub-scanning direction according to the reading characteristics of the reading unit of the first reading unit. Similarly, the second image shift means 17 finely adjusts the mechanical electric shift in the main scanning direction and the sub-scanning direction according to the reading characteristics of the reading unit of the second reading means. As a result, the unique reading positions of the first reading means 11 and the second reading means 12 are corrected.

  The images whose reading positions have been adjusted by the image shift means 16 and 17 are output to the image composition means 18. The image synthesizing unit 18 synthesizes the image data read from the first reading unit 11 and the image data read from the second reading unit 12 on one line in real time. The synthesized image data is subjected to the same image processing by the later common image processing means 19 as the image processing means regardless of the image data from the first reading means 11 and the image data from the second reading means 12. Is done.

  The unique image processing means 21 following the common image processing means 19 is based on the information in which the characteristic amounts of the front and back images are detected by the feature amount detection means 20, that is, the first half of one line, that is, the front image and the back image. To change the image quality parameter. The front and back image data processed by the common image processing means 19 is transmitted from the external I / F means 22 to the external device through the external I / F simultaneously with the front and back surfaces together with a signal indicating the effective image area. In the external device, the image data for the two front and back surfaces is stored in an external memory in a form in which the front and back image data is separated based on the effective image area signal. In some cases, the image data stored in the external device is returned again to the external I / F means 22 via the external I / F and output by the image output means. Reference numeral 23 denotes writing means connected to the external I / F means 22, and 24 denotes image memory control.

  The above operation is controlled by the CPU 26 connected by the bus 25. The CPU 26 stores necessary information in the CPU memory 27 and reads it to control the entire system as a system.

  Next, a description will be given of a case where image processing is performed by the single common image processing unit 19 on the two types of image data from the first reading unit 11 and the second reading unit 12 in the above configuration.

  In FIG. 1, the image data of the front and back read from the first reading means 11 and the second reading means 12 is unified by the pixel rate conversion means 13 and 14, and the image position is changed by the image shifting means 16 and 17. To be unified. The first reading unit 11 and the second reading unit 12 are, for example, a reading device on the front surface side and a reading device on the back surface side in an image processing apparatus capable of simultaneously reading the front surface and the back surface of a document.

  The image data obtained by correcting and standardizing the pixel rate and the image position are combined by the image combining unit 18. FIG. 5 shows the relationship between the image effective area signal and the image data at the time of image synthesis at this time. The image data synthesized in this way can be processed by the common image processing means 19 in the subsequent stage with one system image processing block instead of two systems with separate front and back image processing blocks. Thereby, hardware can be simplified and control becomes easy.

  FIG. 2 shows details of the pixel rate conversion means 13 and 14. There are two types of pixel rates, a pixel rate specific to the first reading unit 11 and a pixel rate specific to the second reading unit 12. If this is the case, it is necessary to divide the subsequent processing block for each pixel rate, which is inefficient. For this reason, it is necessary to unify to one pixel rate. For this reason, the clock generator 15 as a common clock generation unit receives the clock of the first reading unit 11 and the clock of the second reading unit 12 as input signals, and detects which clock is slower.

  As a detection method, for example, rising edges of both clocks are counted within a certain appropriate time, and the pixel rate is faster when the count value is larger within a certain time, and the pixel rate is slower when the count value is smaller. It can be detected. When it is detected which pixel rate is slower in this way, a clock that is twice (integer multiple) the clock frequency of the pixel rate is generated by the PLL. This is a pixel rate clock that is unified by the pixel rate conversion means 13 and 14. When the pixel clock of the first reading unit 11 and the pixel clock of the second reading unit 12 are fixed, a presumed pixel clock may be applied as a common clock.

  As the image data, two dual-port FIFOs are used, the first input clock is the clock of the first reading means 11, and similarly the first output clock is the doubled clock of the later clock of both. Apply. Further, the second input clock is the clock of the second reading means 12, and the second output clock is similarly applied with the doubled clock of the slower clock of both. As a result, the image data of the first reading means 11 entering the first dual port FIFO is converted from the pixel rate of the first reading means 11 to a common pixel rate, and the second reading entering the second dual port FIFO. The image data of the means 12 is converted from the pixel rate of the second reading means 12 to a common pixel rate. As a result, a unified pixel rate is obtained from two different pixel rates, and handling in the subsequent processing 33 and 34 becomes easy.

  FIG. 3 shows the signal processing in this embodiment. For an effective image, there are a main scanning effective area signal and a sub scanning effective area signal indicating that it is an effective area, the main scanning effective area signal is a line gate signal, and the sub scanning effective area signal is a frame gate signal. To do. There is also a line start signal indicating the start position of the front end of main scanning.

  As a shift function in the main scanning direction, the shift position of the main scanning changes depending on where the line gate signal is asserted from the line start signal and then negated. When the line gate signal is moved to the rear end side of the main scan with respect to the image data, the effective image area is shifted to the front end side of the main scan. Similarly, when the run gate signal is moved to the main scanning front end side, the effective image area is shifted to the main scanning rear end side.

  As for the sub-scanning, since the leading edge of the frame gate signal is the start position in the sub-scanning direction, the frame gate signal cannot be moved before the original frame gate signal. Therefore, in the sub-scanning direction, the frame j gate signal can be moved only to the rear end side of the sub-scanning, and the effective image area can only be shifted in the sub-scanning front end direction.

  FIG. 6 shows a signal processing circuit. FIG. 6A shows a circuit for generating a line gate signal indicating an effective image area in the main scanning direction, and FIG. 6B shows an effective image area in the sub-scanning direction. It is a circuit which produces | generates the line gate signal shown. Any circuit is composed of the counters 35, 36 and the comparators 37, 38 and 39, 40, so that the circuit is simple.

  Thus, the image data read from the first reading means 11 and the image data read from the second reading means 12 are generated by moving the line gate signal and the frame gate signal, respectively, so as to appropriately shift the image. can do.

  FIG. 7 shows the image composition means 18. In the image synthesizing unit 18, as shown in FIG. 7C, the surface image data read by the first reading unit 11 applied as an input image may be directly output as an output image. Thus, the surface image data is pasted on the first half of one line. Next, the back side image data read by the second reading means 12 is written to the delay memory from the leading end of the main scanning by the delay memory such as the dual port FIFO memories 41 and 42, and the delayed memory data is read from the latter half of the main scanning. To lead. Thereby, back surface image data can be read from the second half of one line. In FIG. 7C, reference numeral 43 denotes a selector connected to the dual port FIFO memories 41 and 42.

  FIG. 7A is a circuit for generating a line gate signal of a composite image. In this circuit, the read back surface image data is combined with the above-described front surface image data, whereby the first half of one line can be used as the front surface image data and the second half can be used as the back surface image data. The interval between the front surface image data and the back surface image data can be adjusted by changing the timing of reading back surface image data in the latter half of one line from the delay memory. The combined line gate signal at this time is shown in FIG. FIG. 4 shows the relationship between each control signal after synthesis and the image data.

  In FIG. 7C, the back surface image data of the second reading means 12 arranged in the second half of one line is controlled by a delay memory such as the dual port FIFO memories 41 and 42. The back side image data input from the front end of the main scanning is written in the delay memories 41 and 42, and a read line gate signal is applied at a position where the data is to be read out, so that the back side image data is read from an arbitrary position on one line. Can be read. By finely adjusting the readout position, it is possible to easily set the width between the front image of the first half of one line and the back image data of the second half.

  As shown in FIG. 8, the value between the front image data and the back image data, that is, the value of the invalid image area is controlled by the line gate signal H / L indicating the valid image. If the image is H and an invalid image, the image data is selected when the line gate signal is L, and the value of the register 44 that can be arbitrarily set is selected when the line gate signal is H. As a result, the valid area outputs image data, and the invalid area outputs the set value of the register 44, so that the data value of the invalid area can be arbitrarily set.

  FIG. 9 shows the internal configuration of the common image processing means 19. As described above, the image data obtained by combining the front surface image data and the back surface image data has a frame gate signal indicating the effective area of the sub-scanning, a line gate signal indicating the effective area of the main scanning, and a pixel rate unified on the front and back surfaces. An effective image area is indicated by an operating pixel clock and a line start signal indicating the main scanning tip. Therefore, it is possible to perform processing in the same image processing blocks 1 to 4 as if they were one image without separating the back image and the front image. In this way, the image processing block can be configured by one system without configuring the two image processing blocks for the front surface and the back surface. Thereby, an increase in hardware and an increase in design man-hours can be avoided.

  FIG. 10 shows another configuration of the image processing means 19. The front and back unique image processing means 47 in the image processing means 19 is performed by an algorithm that inputs image data and detects the feature amount of the image data. Although this algorithm is not particularly specified in the present invention, for example, there is a feature amount detection block that outputs the feature amount of the image in real time while viewing the input image, and the feature amount on the front and back sides of the document data. Suppose you want to switch levels. For example, if the front side is a photographic image, the back side is a character image, and the characteristics of the image are different between the front side and the back side of the document, it is necessary to change the feature amount detection level accordingly. This is made possible by incorporating a configuration for switching detection parameters between invalid areas between the first half (front image) and the second half (back image). The switching timing can be detected by switching the line gate at the center of one line of the combined line gates in FIG.

  The feature quantity generated in this way is applied to the front and back unique image processing means 47, and the front and back unique image processing means 47 performs image processing using the feature quantity. This makes it possible to perform image processing suitable for the document image on the front and back surfaces.

  The image processing program of the present invention is a program that causes a computer to execute the above processing steps. The recording medium of the present invention is a recording medium on which the image processing program is recorded so as to be readable by a computer.

1 is a block diagram illustrating a configuration of an image processing apparatus according to an embodiment of the present invention. It is a block diagram which shows the circuit which unifies a pixel rate. It is a timing chart which shows the process with respect to a main scanning signal and a subsignal process. It is a timing chart which shows a process with a control signal and image data. It is a timing chart in the case of synthesize | combining front surface image data and back surface image data. (A) And (B) is a circuit diagram for producing | generating a line gate signal and a frame gate signal. (A) is a circuit diagram for combining images, (B) is a timing chart for combining images, and (C) is a circuit diagram for outputting a combined image. It is a circuit diagram for setting an invalid area. It is a block diagram which shows the internal structure of an image processing means. It is a block diagram which shows another structure of an image processing means.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 1st reading means 12 2nd reading means 13 1st pixel rate conversion means 14 2nd pixel rate conversion means 15 Clock generator 16, 17 Image shift means 18 Image composition means 19 Common image processing means 20 Feature-value detection means 21 Unique image Processing means

Claims (16)

Reading means for simultaneously reading the front and back sides of the document;
Pixel rate conversion means for converting the pixel rate of the read front image data and back image data into the same pixel rate;
Image shift means for adjusting the shift in the main scanning direction and the sub-scanning direction of the front surface image data and the back surface image data from the pixel rate conversion means;
Image combining means for combining the front image data and the back image data from the image shift means on the same line;
An image processing apparatus comprising: image processing means for performing the same image processing on the front surface image data and the back surface image data combined by the image combining means. The pixel rate conversion means includes:
Pixel rate detection means for detecting a slow pixel rate from the reading pixel rate of the front surface image data and the reading pixel rate of the back surface image data;
Generating a pixel rate clock that is an integer multiple of the slower pixel rate detected by the pixel rate detecting means;
2. The image processing apparatus according to claim 1, further comprising pixel clock generation means for converting the front surface image data and the back surface image data to the same pixel rate. The image shift means includes
A line gate shift means for moving the relative position of the line gate signal indicating the effective image area of the main scan to the image data in the main scan direction;
Frame gate shift means for moving the relative position of the frame gate signal indicating the effective image area of the sub-scan to the image data in the sub-scan direction;
2. The image processing apparatus according to claim 1, wherein the line gate shift unit and the frame gate shift unit independently control the front surface image data and the back surface image data. The image composition means includes
The front surface image data converted and input by the pixel rate conversion means is output so as to be arranged in the first half of one line, and the back surface image data is outputted so as to be arranged in the second half of one line, and these are output on a single line. The image processing apparatus according to claim 1, wherein the image processing apparatus is combined.   5. The invalid image area width and invalid area data between the front surface image data arranged in the first half of one line and the back image data arranged in the second half of the line are generated by the image composition means. The image processing apparatus described.   The image processing apparatus according to claim 1, wherein the image processing unit performs a common process on the front surface image data and the back surface image data combined by the image combining unit.   The image processing means performs image processing by switching processing parameters in the first half and the second half of one line between the front surface image data arranged in the first half of one line and the rear surface image data arranged in the second half by the image composition means. The image processing apparatus according to claim 1. A reading step for simultaneously reading the front and back sides of the document;
A pixel rate conversion step of converting the pixel rates of the read front surface image data and back surface image data into the same pixel rate;
An image shift step for adjusting a shift in the main scanning direction and the sub scanning direction of the front surface image data and the back surface image data from the pixel rate conversion step;
An image synthesis step of synthesizing the front surface image data and the back surface image data from the image shift step on the same line;
An image processing method comprising: an image processing step for performing the same image processing on the front surface image data and the back surface image data combined in the image combining step. The pixel rate conversion step includes:
A pixel rate detection step of detecting a slow pixel rate from the reading pixel rate of the front surface image data and the reading pixel rate of the back surface image data;
Generating a pixel rate clock that is an integer multiple of the slower pixel rate detected by the pixel rate detecting means;
9. The image processing method according to claim 8, further comprising a pixel clock generation step of converting the front surface image data and the back surface image data to the same pixel rate. The image shift step includes
A line gate shift step for moving a relative position of the line gate signal indicating the effective image area of the main scan with respect to the image data in the main scan direction;
A frame gate shift step of moving a relative position of the frame gate signal indicating the effective image area of the sub scanning with respect to the image data in the sub scanning direction;
9. The image processing method according to claim 8, wherein the line gate shift step and the frame gate shift step control the front surface image data and the back surface image data independently.   The image composition step outputs the front surface image data converted and input by the pixel rate conversion step so as to be arranged in the first half of one line, and outputs the rear surface image data so as to be arranged in the second half of one line. The image processing method according to claim 8, wherein the image processing method is a step of combining images on a single line.   The image synthesizing step is a step of generating invalid area data and invalid area data between the front image data arranged in the first half of one line and the back image data arranged in the second half. The image processing method according to claim 11.   9. The image processing method according to claim 8, wherein the image processing step is a step of performing common processing on the front surface image data and the back surface image data combined in the image combining step.   The image processing step is a step of performing image processing by switching processing parameters in the first half and the second half of one line between the front surface image data arranged in the first half of one line and the back surface image data arranged in the second half in the image combining step. The image processing method according to claim 8.   The image processing program for making a computer perform each step of any one of Claims 8-14.   A computer-readable recording medium on which the image processing program according to claim 14 is recorded.

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