JP2016019267A - Image processing system, image processing method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image processing system capable of obtaining a high-quality image under simple control and without requiring much time in such a case that an image subjected to read is not settled within one field.SOLUTION: The image processing system includes a plurality of sensor modules which are arranged side by side in a direction of document conveyance, each sensor module including a plurality of line sensors arranged side by side in the direction of document conveyance. Different positions on a document are read by the plurality of line sensors, and information acquired from the read positions is integrated by performing temporal delay processing thereon and acquired as image information. For the plurality of sensor modules, the numbers of line sensors to be integrated are set at different values, image information for which information items as many as the set number of line sensors are integrated, is acquired for each of the plurality of corresponding sensor modules, and a plurality of acquired image information items are combined.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an image processing apparatus, an image processing method, and a program.

  In order to expand the dynamic range, a method of reading a plurality of images with different exposure times and combining them is known. For example, Patent Document 1 discloses a method for acquiring images with different exposure times in one field in a digital camera. Japanese Patent Application Laid-Open No. 2004-228561 discloses a method of acquiring a document read under different exposure conditions by a single scan.

  However, conventionally, since the document is read a plurality of times while changing the sensitivity of the CCD and the lamp illuminance, when the image to be read does not fit in one field as in the case of moving the document, the reading position of each image However, there is a problem that high-quality images cannot be obtained because they cannot be combined correctly. Further, the conventional method has a problem that it takes a lot of time to read the document a plurality of times.

  In order to expand the dynamic range, conventionally, as in the technique according to Patent Document 2, complicated control that requires processing under different exposure conditions for each line is necessary. Further, the technique according to Patent Document 2 requires a long time for processing because the scanning speed needs to be slower than normal.

  The present invention has been made in view of such circumstances, and in the case where an image to be read does not fit in one field, a high-quality image can be obtained with a simple control without requiring much time. An object is to provide an image processing apparatus that can be obtained.

  In order to solve the above-described problems, an image processing apparatus according to the present invention includes a plurality of sensor modules arranged in a line along the document conveyance direction. The sensor module includes a plurality of line sensors arranged in a line along the document conveyance direction. An image processing apparatus that reads different positions on a document by a plurality of line sensors, performs time delay processing on information acquired from the read positions, integrates the information, and acquires the information as image information. For the module, integrated line number setting means for setting the number of line sensors to be integrated to different values, and image information obtained by integrating information for the number of line sensors set by the integrated line number setting means, Image acquisition means for acquiring each from the sensor module, and image combining means for combining a plurality of pieces of image information acquired by the image acquisition means Characterized in that it comprises a and.

  According to the present invention, even when the reading target image does not fit in one field, it is possible to obtain a high-quality image with a simple control without requiring much time.

1 is a schematic configuration diagram of an image processing apparatus according to an embodiment of the present invention. It is a schematic diagram explaining the outline of the TDI sensor used for embodiment of this invention. It is a schematic diagram explaining the outline of the TDI sensor module used for embodiment of this invention. It is a schematic diagram explaining the line delay memory line alignment timing in the embodiment of the present invention. It is a schematic block diagram of the read image processing part in the embodiment of the present invention. It is a schematic diagram explaining the image composition process in the embodiment of the present invention.

  An image processing apparatus according to an embodiment of the present invention will be described below with reference to the drawings. However, the present invention is not limited to the present embodiment as long as the gist of the present invention is not exceeded. In addition, in each figure, the same code | symbol is attached | subjected to the part which is the same or it corresponds, The duplication description is simplified thru | or abbreviate | omitted suitably.

  A schematic configuration of an image processing apparatus according to an embodiment of the present invention will be described with reference to FIG. The image processing apparatus according to the present embodiment includes an engine control unit 1 and a controller unit 2. The engine control unit 1 performs, for example, image reading control, image writing control, various image processing, and the like. The controller unit 2 performs, for example, external print data reception, scanner image distribution, and image data storage.

  The engine control unit 1 includes an engine CPU 11, a time delay integration (hereinafter referred to as “TDI”) module 12, an engine memory 13, and a laser diode (hereinafter referred to as “LD”) 14, 15, 16, 17, 18. The engine image processing unit 19 is included.

  The engine image processing unit 19 includes a register I / F 191, a reading control unit 192, a writing control unit 193, an engine internal bus control unit 194, a reading image processing unit 195, a rotator 196, and an editor 197. A writing image processing unit 198 and a serial communication control unit 199.

  The engine CPU 11 performs overall control of the engine control unit 1. The TDI module 12 is composed of a plurality of TDI sensors. In the TDI, a plurality of CCDs arranged on a line are arranged in a plurality of rows in the vertical direction, and an image obtained with a plurality of CCDs is subjected to integral exposure, whereby an image with high sensitivity can be obtained. The TDI module 12 includes an integrated line number setting unit 121. Details of the TDI module 12 and the TDI sensor will be described later.

  The engine memory 13 functions as a line delay storage unit for aligning line data with different exposure amounts received from the reading control unit 192. The engine memory 13 temporarily stores the print image after the total amount restriction process received from the write image processing unit 198. The engine memory 13 may store other data necessary for engine control.

  The LDs 14, 15, 16, 17, and 18 are used for image writing based on the image data received from the writing control unit 193. In the present embodiment, five LDs are provided. However, the present invention is not limited to this, and a configuration in which six or more LDs are provided may be used.

  The register I / F 191 functions as an interface between the engine image processing unit 19 and the engine CPU 11.

  The reading control unit 192 is an image acquisition unit that reads a color image using the TDI module 12. The reading control unit 192 controls the TDI module 12. The writing control unit 193 outputs the image data received from the engine memory 13 to the LDs 14, 15, 16, 17, 18 according to the image forming timing in an image forming station (not shown).

  The engine internal bus control unit 194 performs bus switching and bus arbitration among the reading control unit 192, the writing control unit 193, the reading image processing unit 195, the writing image processing unit 198, the engine memory 13, and the like.

  The read image processing unit 195 includes, for example, correction using the read image modulation or amplitude transfer function, smoothing filter correction, dynamic range synthesis, color correction from an RGB image to a CMYK image, scaling of the read image, and read image data. Perform compression processing.

  For example, when it is desired to change the direction of the image data, the rotator 196 performs processing for replacing the data at the last address with the data at the top address. For example, the editor 197 performs an editing process such as reading out and synthesizing image data from the main memory 13 in accordance with a setting by a register control circuit (not shown), and performing a process of writing back to the main memory 13.

  The writing image processing unit 198 includes, for example, image data expansion processing based on CMYK colors, gradation processing of image data based on CMYK colors, resolution conversion and scaling of stamp image data, copy-forgery-inhibited pattern image data, transparent color image data, An image shift process for each plate, a composition process of each image data, a total toner amount restriction process, and the like are performed.

  The serial communication control unit 199 is an interface that connects the engine control unit 1 and the controller unit 2, and may be configured by a high-speed serial interface such as PCI-Express, for example.

  On the other hand, the controller unit 2 includes a controller CPU 21, a controller memory 22, an HDD 23, an external I / F control unit 24, and a controller image processing unit 25.

  Among these, the controller image processing unit 25 includes an input controller 251, an output controller 252, a controller internal bus control unit 253, a rotator 254, an editor 255, a compressor 256, a decompressor 257, and an HDD controller. 258 and a serial communication control unit 259.

  The controller CPU 21 performs overall control of the controller unit 2. For example, the controller CPU 21 performs translation of image data, drawing of a print image, drawing of a stamp image, drawing of a tint block image, drawing of a transparent color image, compression processing to JPEG data, decompression processing from JPEG data to an image, and the like. .

  The controller memory 22 is a memory for temporarily storing image data received from the outside. The controller memory 22 functions as, for example, a work memory for print images, stamp images, copy-forgery-inhibited pattern images, transparent color images, normal color images, and read images. Furthermore, the controller memory 22 also functions as a memory that stores various programs.

  The HDD 23 is a mass storage device that stores image data and the like. In the present embodiment, the HDD 23 is built in the controller unit 2, but is not limited thereto, and may be an external configuration.

  The external I / F control unit 24 is an interface connected to an external communication device via a network (not shown). The external I / F control unit 24 controls, for example, image transfer to an external device, image data input processing from the external device, and the like.

  The input controller 251 receives image data from the engine control unit 1. On the other hand, the output controller 252 sends image data to the engine control unit 1.

  The controller internal bus control unit 253 performs bus switching and bus arbitration between the functional blocks in the controller image processing unit 25. The description of the rotator 254 and the editor 255 is omitted because it overlaps with the description of the rotator 196 and the editor 197 in the engine image processing unit 19.

  The compressor 256 performs data compression when storing read image data or the like in the HDD 23 or the like. On the other hand, the decompressor 257 performs processing for returning the compressed saved data to the original read image data or the like.

  The HDD controller 258 controls the HDD 23. The serial communication control unit 259 is an interface that connects the engine control unit 1 and the controller unit 2 via the serial communication control unit 199 described above.

  Next, an outline of the TDI sensor used in the present embodiment will be described with reference to FIG. In the present embodiment, a plurality of TDI modules 12 as sensor modules may be arranged side by side along the conveyance direction of the read document. The TDI module 12 is arranged side by side along the conveyance direction of the read document, and includes a TDI sensor as a plurality of line sensors for reading different positions on the document and an integrated line number setting unit 121. Hereinafter, the TDI sensor will be specifically described.

  In the figure, a TDI sensor having 256 stages capable of varying the integration line is shown. Here, a line-shaped CCD stage in which 7680 CCD pixels C1 to C7680 are arranged in the horizontal direction is arranged in the vertical direction for 256 lines from row (hereinafter referred to as “Row”) 1 to Row256. The integration line is not limited to 256 stages, and may be appropriately changed according to the specifications of the apparatus.

  The charges accumulated on each CCD stage are transferred by one stage at a time in the vertical direction by one vertical clock signal.

  For example, first, when the number of integrated lines is set to a maximum of 256 lines by an external signal, an image of 7680 pixels imaged at Row 256 at a certain point moves by one stage in the vertical direction. When a vertical clock signal is given in synchronization therewith, the line image picked up by Row 256 is transferred to Row 255. Therefore, since the same image is continuously captured, the charge of the accumulated image is doubled. Therefore, the exposure amount is doubled.

  Subsequently, when the image further moves one stage in the vertical direction and a synchronizing clock signal is given, the accumulated image is transferred to Row 254, where three times as much image charge is accumulated. Thereafter, when transfer to Row 1 is completed in sequence, 256 times the image charge is serially extracted from the horizontal shift register as image data.

  The above operation is performed simultaneously in each of the stages Row1 to Row256. Then, while sending a two-dimensional image consisting of 7680 pixels × 256 pixels vertically, an image in which 256 times the charge has been accumulated can be taken out synchronously line by line.

  In the present embodiment, it is preferable that the integrated line number setting unit 121 shown in FIG. 1 sets the number of line sensors integrated to a plurality of TDI sensor modules to different values, that is, varies. The reading control unit 192 preferably acquires image information obtained by integrating information corresponding to the number of line sensors set by the integrated line number setting unit 121 from a plurality of corresponding sensor modules.

  For example, when the number of line sensors to be integrated is set to 32, the transfer charge is cut at the line-shaped portion indicated by CUT 32. As a result, the accumulated charge is limited to Row 1 to Row 32. In addition, the number of line sensors to be integrated that can be set in this figure can be selected from six types of 256 steps, 128 steps, 64 steps, 32 steps, 16 steps, and 8 steps, but is not limited to this. As the number increases, the number of line sensors to be integrated may be increased as appropriate.

  Next, an outline of the TDI module 12 used in the present embodiment will be described with reference to FIG. As shown in the figure, in the TDI module 12 of the present embodiment, three exposure amounts for RGB can be set.

  For example, if the TDI sensors of Red1, Green1, and Blue1 are set to 256 stages, 256 times RGB line data can be extracted as the exposure amount. If the TDI sensors of Red1, Green1, and Blue1 are set to 128 stages, 128 times of RGB line data can be extracted as the exposure amount. Further, if the Red1, Green1, and Blue1 TDI sensors are set to 64 stages, it is possible to extract RGB line data of 64 times as the exposure amount.

  That is, by changing the number of stages of the TDI sensor, it is possible to extract RGB line data with different exposure amounts. The line gap between the line data is required for 256 lines of the TDI sensor.

  Next, line delay memory line alignment timing and time delay processing in this embodiment will be described with reference to FIG. Each image data is read by the reading control unit 192 in a state of being delayed by the line gap between the line data from the TDI sensor.

  These image data are sequentially written in the engine memory 13 by the writing control unit 193, and the reading image processing unit 195 starts reading image data from the engine memory 13 from the time when writing of b3_data in the last line is started. The read image processing unit 195 reads the read timings of the plurality of image data stored in the engine memory 13 in synchronization with all nine types of RGB images. Thereby, the tops of the pixels can be aligned.

  Next, a schematic configuration and image composition processing of the read image processing unit 195 in the present embodiment will be described with reference to FIG. The read image processing unit 195 includes three shading correction units 301, 302, and 303, three filter processing units 304, 305, and 306, an image composition unit 307, a color correction unit 308, and a scaling unit corresponding to the three shading correction units 301, 302, and 303, respectively. The unit 309 is configured.

  The image data read from the engine memory 13 is sent to the three shading correction units 301, 302, and 303 for each RGB set having different exposure amounts, and shading correction is performed.

  Here, for example, “r1_rd”, “g1_rd”, and “b1_rd” are sent to the shading correction unit 301 as image data. Also, “r2_rd”, “g2_rd”, and “b2_rd” are sent to the shading correction unit 302 as image data. Further, “r3_rd”, “g3_rd”, and “b3_rd” are sent to the shading correction unit 302 as image data.

  Thereafter, each image data subjected to the shading correction is sent to the three filter processing units 304, 305, and 306, and the filter processing is performed.

  Here, for example, “r1_sh”, “g1_sh”, and “b1_sh” are sent to the filter processing unit 304 as image data after shading correction. Further, “r2_sh”, “g2_sh”, and “b2_sh” are sent to the filter processing unit 305 as the image data after shading correction. Further, “r3_sh”, “g3_sh”, and “b3_sh” are sent to the filter processing unit 306 as image data after shading correction.

  Then, the image data that has undergone the filter processing is sent to the image composition unit 307. Here, for example, “r1_fl”, “g1_fl”, “b1_fl”, “r2_fl”, “g2_fl”, “b2_fl”, “r3_fl”, “g3_fl”, “b3_fl” are the image data after filtering. The data is sent to the synthesis unit 307. The image composition unit 307 performs dynamic range composition using RGB sets having a plurality of exposure amounts and having different exposure amounts.

  The synthesized image is converted from an RGB image to a CMYK image by the color correction unit 308 or processed as it is as an RGB image. Thereafter, the scaling unit 309 enlarges or reduces the image to the designated size.

  Next, the image composition processing in this embodiment will be described with reference to FIG. In the present embodiment, the image composition unit 307 illustrated in FIG. 5 includes a first threshold for determining image degradation in high-exposure image information, and a second threshold for determining image degradation in low-exposure image information. It is preferable to determine image information to be synthesized based on.

  Then, the image composition unit 307 may replace the high-exposure image information determined to be image degradation by the first threshold value with at least the low-exposure image information rather than the high-exposure image information. On the other hand, the image composition unit 307 may replace the low-exposure image information determined to be image degradation by the second threshold with at least high-exposure image information than the low-exposure image information.

  As shown in FIG. 6, regarding the generation of a dynamic range image by image composition, the horizontal axis represents the pixel value of the image input to the image composition unit 307 and is converted to light intensity, and the vertical axis is generated. The output pixel value of the dynamic range image is taken. That is, this figure represents the input / output characteristics of the pixel values for the image composition unit 307.

  In this figure, the line segment L1 shows the input / output characteristics of the high exposure image, the line segment L2 shows the input / output characteristics of the medium exposure image whose exposure time is shorter than L1, and the line segment L3 has the exposure time shorter than L2. The input / output characteristics of the exposure image are shown. In the present embodiment, the high exposure image means image data acquired when the number of stages of the TDI sensor is set, and the low exposure image means image data acquired when the number of stages of the TDI sensor is set small. Say.

  Here, in the input / output characteristics L1 of the high exposure image and the input / output characteristics L2 of the medium exposure image, the threshold value of light intensity that can be regarded as overexposure on the image is set as the sh2 value. ". In other words, a value larger than sh2 is an area where gradation is lost due to overexposure.

  On the other hand, a low-exposure image with a short exposure time is read before saturation, and therefore, even in a region where white highlighting occurs, it is possible to read without impairing gradation. Therefore, it is possible to improve image degradation such as white stripes by replacing a region having a light intensity greater than the threshold sh2 with a value of a low exposure image.

  On the other hand, in the input / output characteristics L3 of the low exposure image and the input / output characteristics L2 of the middle exposure image, the threshold value of light intensity that can be regarded as black stripes on the image is set as the value of sh1, and this is the above-described "second threshold value" Corresponding to In other words, a value smaller than sh1 is a region where the gradation is lost due to black stripes. By replacing the area with the value of the high-exposure image, it is possible to improve image deterioration such as black stripes.

  Furthermore, by replacing the area between sh1 and sh2 with the value of the medium exposure image, it is possible to improve image deterioration such as gradation skipping.

  As described above, in the present embodiment, a plurality of TDI sensors are arranged in the sub-scanning direction, and each TDI sensor adjusts the exposure amount by making the integration line variable. As a result, even in a document feeder or the like that reads a document while moving it, line data with different exposure amounts are sequentially read from different TDI sensors in a single document reading operation, and the same pixel is read by way of a line delay memory. Align the lines and compose the image. As a result, an image with an expanded dynamic range can be created without performing multiple reading operations.

  Each of the above-described embodiments is a preferred embodiment of the present invention, and various modifications can be made without departing from the scope of the present invention. For example, each process in the above-described image processing apparatus of the present embodiment can be executed using hardware, software, or a combined configuration of both.

  In the case of executing processing using software, it is possible to install and execute a program in which a processing sequence is recorded in a memory in a computer incorporated in dedicated hardware. Alternatively, the program can be installed and executed on a general-purpose computer capable of executing various processes.

1 Engine control unit 2 Controller unit 11 Engine CPU
12 TDI module 13 Engine memory 14, 15, 16, 17, 18 Laser diode 19 Engine image processing unit 21 Controller CPU
22 Controller memory 23 HDD
24 External I / F Control Unit 25 Controller Image Processing Unit 191 Register I / F
192 Reading control unit 193 Writing control unit 194 Engine internal bus control unit 195 Reading image processing unit 196, 254 Rotator 197, 255 Editor 198 Writing image processing unit 199, 259 Serial communication control unit 251 Input controller 252 Output controller 253 Controller internal bus control unit 256 Compressor 257 Expander 258 HDD controller 301, 302, 303 Shading correction unit 304, 305, 306 Filter processing unit 307 Image composition unit 308 Color correction unit 309 Scaling unit

Japanese Patent No. 3508736 JP 2008-228190 A

Claims (7)

A plurality of line sensors arranged side by side along the document conveyance direction, and a plurality of sensor modules arranged side by side along the document conveyance direction; An image processing device that reads and accumulates information acquired from the read position by performing time delay processing, and acquires the information as image information,
For the plurality of sensor modules, integrated line number setting means for setting the number of line sensors to be integrated to different values, and
Image acquisition means for acquiring the image information obtained by integrating the information for the number of line sensors set by the integrated line number setting means from the corresponding sensor modules;
Image combining means for combining a plurality of the image information acquired by the image acquisition means;
An image processing apparatus comprising:   The image synthesizing unit is a synthesis target based on a first threshold value for determining image degradation in the image information with high exposure and a second threshold value for determining image degradation in the image information with low exposure. The image processing apparatus according to claim 1, wherein the image information is determined.   3. The image synthesizing unit replaces the high-exposure image information determined to be image degradation by the first threshold with at least the low-exposure image information than the high-exposure image information. The image processing apparatus described.   3. The image combining means replaces the low-exposure image information determined to be image degradation by the second threshold value with at least the image information that is higher exposure than the low-exposure image information. Or the image processing apparatus of 3. Storage means for storing a plurality of pieces of the image information acquired by the image acquisition means delayed by a line gap of the line sensor;
5. The image processing apparatus according to claim 1, wherein the image synthesizing unit reads out the read timings of the plurality of pieces of image information stored in the storage unit in synchronization with each other. A plurality of line sensors arranged side by side along the document conveyance direction are included in a plurality of sensor modules arranged side by side along the document conveyance direction, and different positions on the document are read and acquired from the read positions. An image processing method for performing time delay processing on the obtained information and integrating the acquired information as image information,
A step of setting the number of line sensors to be integrated to different values for the plurality of sensor modules;
Obtaining the image information obtained by accumulating information for the set number of line sensors from the corresponding plurality of sensor modules, and
Synthesizing the plurality of acquired image information;
An image processing method comprising: A plurality of line sensors arranged side by side along the document conveyance direction, and a plurality of sensor modules arranged side by side along the document conveyance direction; A program that is executed by an image processing device that reads and accumulates information obtained from a read position by performing time delay processing, and acquires the information as image information.
A process for setting the number of line sensors to be integrated to different values for the plurality of sensor modules;
Processing for acquiring the image information obtained by integrating the information for the number of the set line sensors from the corresponding sensor modules;
A process of combining the plurality of acquired image information;
The program characterized by including.

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