JP2018152751A - Image processing apparatus, image processing method, and image processing program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To calculate a pixel value of an interpolated pixel even when a pixel area used for calculating a pixel value of an interpolated pixel overlaps with another pixel area. SOLUTION: In the image data acquired for each line in the main scanning direction, a means for determining a matching region and a pixel to be processed next when the process of interpolating the Nth missing pixel is performed. A means for determining whether or not it is included in the (N + 1) th matching area, and a (N + 1) th matching with respect to the line buffer for storing the image data when it is included in the (N + 1) th matching area. By accessing the first address of the addresses corresponding to each pixel included in the region, the pixel value of each pixel is sequentially read out, and based on the read pixel value, (N + 1). It has a means for interpolating the second missing pixel. [Selection diagram] FIG. 8

Description

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

  2. Description of the Related Art Conventionally, an image forming apparatus such as an MFP (Multi-Function Peripheral) has a scanner unit that scans a document, and an image processing device processes a signal detected by a reading device so that a scanned document can be scanned. Generate image data.

  Generally, an image processing device in a scanner unit has an interpolation function that interpolates the pixel value of a corresponding pixel (missing pixel) with the pixel value of another pixel when a part of the detected signal is missing. Is arranged. As a specific example, Patent Document 1 below discloses an interpolation method for interpolating a missing pixel by performing pattern matching using a pixel region around the missing pixel and extracting a pattern similar to the pattern including the missing pixel. Has been.

  However, in the case of the above interpolation method, it is assumed that the pixel areas used for pattern matching between the Nth missing pixel and the (N + 1) th missing pixel do not overlap each other.

  On the other hand, in order to improve the interpolation accuracy, for example, when the pixel region used for pattern matching is expanded, it is conceivable that the pixel region overlaps with the Nth missing pixel and the (N + 1) th missing pixel. In such a case, the above interpolation method has a problem that the pixel value of the interpolation pixel cannot be calculated appropriately.

  The present invention has been made in view of the above problems, and an object of the present invention is to make it possible to calculate the pixel value of an interpolation pixel even when the pixel area used for calculating the pixel value of the interpolation pixel overlaps with another pixel area. And

The image processing apparatus according to each embodiment of the present invention has the following configuration. That is,
Determining means for determining a pixel region used for calculating a pixel value of an interpolation pixel for interpolating a missing pixel in image data acquired for each line in the main scanning direction;
Of the image data, when the process of interpolating the Nth missing pixel is performed based on the pixel value of each pixel included in the Nth pixel area, the next pixel to be processed is ( Determination means for determining whether or not the pixel area is included in the (N + 1) th pixel region;
When it is determined that the pixel data is included in the (N + 1) th pixel area, an address corresponding to each pixel included in the (N + 1) th pixel area is stored in the memory storing the image data for one line. A read control means for accessing the head address of the pixels and sequentially reading out the pixel values of the pixels included in the (N + 1) -th pixel area;
Interpolating means for interpolating the (N + 1) th missing pixel based on the pixel value of each pixel included in the (N + 1) th pixel area read by the readout control means, To do.

  According to each embodiment of the present invention, the pixel value of the interpolation pixel can be calculated even when the pixel area used for calculating the pixel value of the interpolation pixel overlaps with another pixel area.

It is a figure which shows an example of the hardware constitutions of a scanner unit. It is a figure for demonstrating the cause of a missing pixel. It is a figure which shows an example of the interpolation process at the time of using a general image processing device. It is a figure which shows an example of the interpolation process at the time of using a general image processing device. It is a figure which shows an example of the interpolation process at the time of using the image processing device which concerns on 1st Embodiment. It is a figure which shows an example of the interpolation process at the time of using the image processing device which concerns on 1st Embodiment. It is a figure which shows an example of the output control signal which performs an output limitation with respect to the pixel stored in the buffer for a matching process, and an output buffer in each timing. It is a figure which shows an example of a function structure of an image processing device. It is a flowchart which shows the flow of the image processing by an image processing device. It is a flowchart which shows the flow of an interpolation process.

  Details of each embodiment will be described below with reference to the accompanying drawings. In the description of the specification and drawings according to each embodiment, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

[First Embodiment]
<1. Hardware configuration of scanner unit>
First, the hardware configuration of the scanner unit having the image processing device according to the first embodiment will be described. FIG. 1 is a diagram illustrating an example of a hardware configuration of the scanner unit.

  As shown in FIG. 1, the scanner unit 110 is mounted on an image forming apparatus 100 such as an MFP. The scanner unit 110 includes a CPU (Central Processing Unit) 111, a ROM (Read Only Memory) 112, and a RAM (Random Access Memory) 113. Further, the scanner unit 110 includes an image processing device 114, an I / F (Interface) device 115, and a reading device 116.

  The CPU 111 executes various programs stored in the ROM 112 and controls the entire scanner unit 110 (or the entire image forming apparatus 100 including units other than the scanner unit 110).

  The ROM 112 is a nonvolatile memory and functions as a main storage unit that stores various programs executed by the CPU 111. A RAM 113 is a volatile memory, and functions as a main storage unit that provides a work area that is expanded when various programs stored in the ROM 112 are executed by the CPU 111.

  The image processing device 114 is a dedicated integrated circuit, and processes and outputs image data about a scanned document generated based on a signal detected by a reading device.

  The I / F device 115 is connected to other units in the image forming apparatus 100 and functions as a connection unit for transmitting and receiving image data processed by the image processing device 114.

  The reading device 116 can detect a range greater than the document width by arranging a plurality of sensor chips in a row (or can detect a range greater than the document width by arranging a long line sensor). It is a reading device. The reading device 116 generates image data for the scanned document based on a signal detected by scanning the document, and inputs the generated image data to the image processing device 114.

<2. Causes of missing pixels>
Next, the cause of occurrence of missing pixels in the image data generated based on the signal detected by the reading device 116 will be described. FIG. 2 is a diagram for explaining a cause of occurrence of a missing pixel.

  Among these, FIG. 2A is a diagram for explaining the cause of occurrence of missing pixels in the reading device 116a in which a plurality of sensor chips 210_1 to 210_n are arranged in a line. As shown in FIG. 2A, when a plurality of sensor chips 210_1 to 210_n are arranged in a line, a physical gap (see gaps 211, 212, etc.) is generated between the sensor chips, and a position corresponding to the gap. Then, the signal cannot be detected.

  For this reason, in the image data 220 generated based on the signal detected by the reading device 116a, the pixels 221 and 222 corresponding to the gaps 211 and 212 are missing pixels.

  FIG. 2B is a diagram for explaining a cause of occurrence of a missing pixel in the reading device 116b in which the long line sensor 230 is arranged. In the case of the long line sensor 230, missing pixels due to a physical gap do not occur. However, as illustrated in FIG. 2B, when the detected signal 240 includes noise, the pixel 251 corresponding to the elements 231 and 232 in the image data 250 generated based on the signal 240. , 252 are missing pixels.

  It should be noted that not only the long line sensor 230 but also the sensor chips 210_1 to 210_n as shown in FIG. 2A, when noise is included in the detected signal, the corresponding pixels are similarly Missing pixels.

  As described above, in the case of image data generated based on a signal detected by the reading device 116, missing pixels are generated due to various reasons. However, in the following, for simplification of description, a case will be described in which the image processing device 114 performs an interpolation process for a case in which a missing pixel is generated due to the cause described with reference to FIG.

  In addition, when a missing pixel occurs for the reason described with reference to FIG. 2B, a case where the occurrence interval of the missing pixel is short and a case where it is long are mixed. Therefore, in the image processing device 114 during the interpolation process, the pixel area around the missing pixel used for pattern matching (referred to as “matching area”) does not overlap with the case where the other missing pixel matching areas overlap. Will be mixed.

  Therefore, in the following, an interpolation process of the image processing device 114 when a case where the matching area overlaps with another matching area and a case where the matching area does not overlap will be described. In the description, as a comparative example, first, interpolation processing when a general image processing device is used will be described (see <3.1> below), and then the image processing device 114 according to the present embodiment. Interpolation processing when using is described (see <3.2> below).

<3. Explanation of interpolation processing>
<3.1 Description of Interpolation Processing Using a General Image Processing Device>
First, interpolation processing when a general image processing device is used will be described. 3 and 4 are diagrams illustrating an example of interpolation processing when a general image processing device is used, and cases where matching regions overlap and cases that do not overlap exist between adjacent missing pixels. The interpolation process is shown. In executing the interpolation process, it is assumed that a general image processing device grasps in advance that an event that causes a missing pixel has occurred and determines a matching area.

  A general image processing device, when acquiring image data 250 for one line in the main scanning direction, determines whether a pixel to be processed is included in the matching region or not in the matching region. In the example of FIG. 3A, since the pixel to be processed is included in the matching region 301, a general image processing device stores the pixel value of the pixel to be processed in the buffer 310 for matching processing.

  When all the pixel values of each pixel included in the matching area 301 are stored in the matching processing buffer 310, the matching processing unit performs matching processing using pattern data prepared in advance. Accordingly, the matching processing unit calculates the pixel value 311 of the interpolation pixel.

  When the pixel value 311 of the interpolation pixel is calculated, a general image processing device inserts the pixel value 311 of the interpolation pixel at a position corresponding to the missing pixel of each pixel stored in the matching processing buffer 310. Then, the pixel value of each pixel stored in the matching processing buffer 310 is stored in the output buffer 320.

  When the matching processing for the matching region 301 is completed, as shown in FIG. 3B, in a general image processing device, the pixel 331 next to the processed pixel in the image data 250 is processed as a processing target pixel. I do. Specifically, it is determined whether or not the pixel to be processed is included in the matching area. If it is determined that the pixel is included, the pixel value of the pixel is stored in the matching processing buffer 310.

  Therefore, in the case of a general image processing device, the matching processing buffer 310 stores the pixel value of the pixel 331. That is, in the case of a general image processing device, it is not possible to store all the pixel values of each pixel included in the matching area 302 in the matching processing buffer 310. In the example of FIG. 3B, the pixel value for two pixels (pixel values of pixels included in the region overlapping with the matching region 301) is not stored in the buffer 310 for matching processing. As a result, the matching processing unit cannot use all the pixel values of each pixel included in the matching region 302 during the matching process, and cannot appropriately calculate the pixel value 312 of the interpolation pixel.

  Thus, in the case of a general image processing device, if the matching region overlaps with other matching regions between adjacent missing pixels, the pixel value of the interpolation pixel cannot be calculated appropriately, and the output buffer 320 The missing pixel 321 is stored.

  However, even in the case of a general image processing device, if the matching area does not overlap with other matching areas (when there are pixels that are not included in the matching area between other matching areas) The pixel value of the interpolation pixel can be calculated appropriately.

  FIG. 4A shows the processing of a general image processing device when the pixel to be processed is not included in any matching region. When the pixel to be processed is not included in any of the matching regions, a general image processing device stores the pixel value of the pixel to be processed in the output buffer 320.

  Further, FIG. 4B shows processing of a general image processing device when the pixel to be processed is included in the matching region 303 (matching region that does not overlap with other matching regions). When the pixel to be processed is included in the matching region 303 (matching region that does not overlap with other matching regions), a general image processing device stores the pixel value of the pixel to be processed in the buffer 310 for matching processing.

  When all the pixel values of each pixel included in the matching region 303 are stored in the matching processing buffer 310, the matching processing unit performs matching processing using pattern data prepared in advance. Accordingly, the matching processing unit calculates the pixel value 313 of the interpolation pixel.

  When the pixel value 313 of the interpolation pixel is calculated, in a general image processing device, the pixel value 313 of the interpolation pixel is inserted into a position corresponding to the missing pixel of each pixel stored in the matching processing buffer 310. Then, the pixel value of each pixel stored in the matching processing buffer 310 is stored in the output buffer 320.

  As described above, in the case of a general image processing device, when the matching area does not overlap with other matching areas between adjacent missing pixels, the pixel value of the interpolation pixel can be appropriately calculated.

<3.2 Explanation of Interpolation Processing Using Image Processing Device According to this Embodiment>
Next, an interpolation process when the image processing device 114 according to the present embodiment is used will be described. In the image processing device 114 according to the present embodiment, the interpolation process is performed so that the pixel value of each interpolation pixel can be appropriately calculated regardless of whether the matching area overlaps with other matching areas or not. FIGS. 5 and 6 are diagrams illustrating an example of interpolation processing when the image processing device according to the first embodiment is used, and a case where matching regions overlap between adjacent missing pixels and a case where they do not overlap It shows the case where is mixed. In executing the interpolation process, it is assumed that the image processing device 114 knows in advance that an event that causes a missing pixel has occurred and determines a matching region.

  As shown in FIG. 5A, the image processing device 114 according to the present embodiment includes a line buffer 510 that stores image data 250 for one line in the main scanning direction. The pixel value of each pixel is sequentially stored in the line buffer 510.

  Further, the image processing device 114 according to the present embodiment determines whether or not the pixel to be processed is included in the matching region among the pixels of the stored image data 250. In the example of FIG. 5A, since the pixel to be processed is included in the matching region 301, the image processing device 114 reads out the pixel value of the pixel to be processed from the line buffer 510 and stores it in the buffer 520 for matching processing. To do.

  When all pixel values of each pixel included in the matching area 301 are read from the line buffer 510 and stored in the matching processing buffer 520, the matching processing unit performs matching processing using pattern data prepared in advance. Accordingly, the matching processing unit calculates the pixel value 521 of the interpolation pixel.

  When the pixel value 521 of the interpolation pixel is calculated, the image processing device 114 inserts the pixel value 521 of the interpolation pixel at a position corresponding to the missing pixel 511 of each pixel stored in the matching processing buffer 520. Then, the pixel value of each pixel stored in the matching processing buffer 520 is stored in the output buffer 530.

  When the matching process for the matching area 301 is completed, the image processing device 114 determines whether or not the pixel 331 next to the processed pixel is included in the matching area. In the example of FIG. 5B, since the pixel 331 is included in the matching area 302, the image processing device 114 reads out the pixel value of each pixel included in the matching area 302 from the line buffer 510, and the matching processing buffer. Stored in 520.

  Here, in the case of the image processing device 114, the pixel value of each pixel of the image data 250 is stored in the line buffer 510. Therefore, the image processing device 114 can read the pixel value of each pixel included in the matching area 302 retrospectively from the line buffer 510.

  Specifically, the image processing device 114 accesses the head address among the addresses corresponding to the respective pixels included in the matching area 302 on the line buffer 510. Thereby, the image processing device 114 can sequentially read out the pixel values of each pixel included in the matching region 302 from the line buffer 510.

  When all the pixel values of each pixel included in the matching area 302 are stored in the matching processing buffer 520, the matching processing unit performs matching processing using pattern data prepared in advance. Accordingly, the matching processing unit calculates the pixel value 522 of the interpolation pixel.

  When the pixel value 522 of the interpolation pixel is calculated, the image processing device 114 inserts the pixel value 522 of the interpolation pixel at a position corresponding to the missing pixel 512 of each pixel stored in the matching processing buffer 520. Then, the pixel value of each pixel stored in the matching processing buffer 520 is stored in the output buffer 530. However, the first two pixels among the pixels stored in the matching processing buffer 520 are already stored in the output buffer 530 together with the pixel value 521 of the interpolation pixel. Accordingly, here, among the pixels stored in the matching processing buffer 520, the pixel values of the pixels excluding the pixels in the overlapping region with the matching region 301 are stored in the output buffer 530 together with the pixel value 522 of the interpolation pixel. .

  As described above, in this embodiment, the line buffer 510 is arranged in the image processing device 114 and the acquired image data is sequentially stored. Thus, according to the image processing device 114, the pixel value of each pixel included in the matching region can be read from the line buffer 510 and stored in the matching processing buffer 520.

  In this embodiment, when reading from the line buffer 510, an address corresponding to each pixel included in the matching area is accessed. That is, the image processing device 114 accesses the line buffer 510 according to the address corresponding to each pixel included in the (N + 1) th matching area regardless of the address at the time when the matching process is completed for the Nth matching area.

  Thus, according to the image processing device 114, even when the matching regions overlap, all the pixel values of each pixel included in the matching region can be read out and stored in the matching processing buffer 520. The pixel value can be calculated appropriately.

  In the image processing device 114 according to the present embodiment, even when the matching region does not overlap with other matching regions between adjacent missing pixels, by performing the same interpolation processing as the above general image processing device, The pixel value of the interpolation pixel is appropriately calculated.

  FIG. 6A shows the processing of the image processing device 114 when the pixel to be processed is not included in any matching region. When the pixel to be processed is not included in any of the matching regions, the image processing device 114 reads the pixel value of the pixel to be processed from the line buffer 510 and stores it in the output buffer 530 as it is.

  FIG. 6B shows the processing of the image processing device 114 when the pixel to be processed is included in the matching region 303 (a matching region that does not overlap with other matching regions). When the processed next pixel 332 is included in the matching region 303, the image processing device 114 reads the pixel value of each pixel included in the matching region 303 from the line buffer 510 and stores it in the matching processing buffer 520. .

  Specifically, the image processing device 114 accesses the head address (in this case, the address corresponding to the pixel 332) among the addresses corresponding to each pixel included in the matching area 303 on the line buffer 510. Thereby, the image processing device 114 can sequentially read out the pixel values of each pixel included in the matching region 303 from the line buffer 510.

  When all the pixel values of each pixel included in the matching area 303 are stored in the matching processing buffer 520, the matching processing unit performs matching processing using pattern data prepared in advance. Accordingly, the matching processing unit calculates the pixel value 523 of the interpolation pixel.

  When the pixel value 523 of the interpolation pixel is calculated, the image processing device 114 according to the present embodiment inserts the pixel value 523 of the interpolation pixel at a position corresponding to the missing pixel in each pixel stored in the matching processing buffer 520. To do. Then, the pixel value of each pixel stored in the matching processing buffer 520 is stored in the output buffer 530.

  Thereby, in the image processing device according to the present embodiment, it is possible to appropriately calculate the pixel value of the interpolation pixel even when the matching region does not overlap with other matching regions between adjacent missing pixels.

  As described above, the image processing device 114 controls to read out all pixel values of each pixel included in the matching area regardless of whether or not the matching area overlaps with other matching areas. Then, when the data is stored in the output buffer, the pixels read out redundantly are adjusted.

  In other words, in the case where the matching areas overlap, the image processing device 114 rearranges the matching processing buffer 520 according to the matching area overlap, and then stores the pixel values. Then, when the stored pixel value is stored in the output buffer 530, output restriction is performed according to the overlapping of the matching areas.

  In addition, in the image processing device 114, when matching regions do not overlap, pixel values are stored in the matching processing buffer 520 without being rearranged. Then, when the stored pixel value is stored in the output buffer 530, it is output without performing output restriction.

  FIG. 7 is a diagram illustrating an example of an output control signal for performing output restriction on the pixels stored in the matching processing buffer and the output buffer at each timing. The number of each pixel is a number given for convenience, and the same number indicates that the pixel value of the same pixel is stored.

  As shown in FIG. 7A, at the timing 701, the pixel values of the pixels 1 to 9 are stored in the buffer 520 for matching processing. At timing 702, the pixel values of the pixels 8 to 16 are stored in the matching processing buffer 520. The pixel stored at the timing 702 is a pixel included in a matching area that overlaps with another matching area. Therefore, the matching processing buffer 520 stores the pixel values of the pixels that have been rearranged according to the overlapping matching regions. Further, as shown in FIG. 7B, the stored pixel values are stored in the output buffer 530 under the output restriction (see reference numeral 711) according to the overlap of the matching areas.

  On the other hand, as illustrated in FIG. 7A, the pixel 19 to the pixel 27 are stored in the matching processing buffer 520 at the timing 703. The pixels stored at the timing 703 are pixels included in a matching area that does not overlap with other matching areas. Therefore, the pixel values are stored in the matching processing buffer 520 without rearranging the pixel values. Further, as shown in FIG. 7B, the stored pixel values are stored in the output buffer 530 without being limited in output (see reference numeral 712).

<4. Functional configuration of image processing device>
Next, the functional configuration of the image processing device 114 will be described. FIG. 8 is a diagram illustrating an example of a functional configuration of the image processing device. As illustrated in FIG. 8, the image processing device 114 includes an interpolation position information acquisition unit 810, a matching region determination unit 820, an image data acquisition unit 830, a read control unit 840, a matching processing unit 850, and an output control unit 860.

  The interpolated position information acquisition unit 810 grasps in advance the element in which an event that causes a missing pixel occurs among the elements of the reading device 116, and indicates the position of the element in which the event occurs. Interpolation position information including is acquired. The interpolation position information acquisition unit 810 notifies the matching area determination unit 820 of the acquired interpolation position information.

  The matching area determination unit 820 is an example of a determination unit, and determines a matching area based on the interpolation position information notified from the interpolation position information acquisition unit 810. When the interpolation position information includes information indicating a plurality of positions, the matching area determination unit 820 determines a matching area for each piece of information indicating each position. The matching area determination unit 820 notifies the read matching unit 840 of the determined matching area.

  The image data acquisition unit 830 acquires image data generated based on signals detected by each element of the reading device 116 and stores the acquired image data in the line buffer 510.

  The readout control unit 840 is an example of a determination unit, and determines whether or not the processing target pixel is included in the matching region notified from the matching region determination unit 820.

  The read control unit 840 is also an example of a read control unit. When it is determined that the pixel to be processed is not included in the matching area, an address corresponding to the pixel to be processed is set as a read address (read destination of the line buffer 510). Address). Further, the read control unit 840 accesses the line buffer 510 based on the set read address, reads the pixel value, and transmits it to the output control unit 860.

  In addition, when it is determined that the pixel to be processed is included in the matching area, the read control unit 840 identifies an address corresponding to each pixel included in the matching area. Further, the read control unit 840 sets the head address of the identified addresses as a read address and accesses the line buffer 510 to sequentially read the pixel values of each pixel included in the matching area. Further, the read control unit 840 stores the pixel values sequentially read from the line buffer 510 in the matching processing buffer 520.

  More specifically, the read address when the matching process is completed for the Nth matching region is an address corresponding to the last pixel of the Nth matching region. For this reason, when the next pixel to be processed is included in the (N + 1) th matching region, the read control unit 840 determines the first of the addresses corresponding to each pixel included in the (N + 1) th matching region. Use the address to change the read address setting. As a result, the readout control unit 840 can sequentially read out the pixel values of each pixel included in the (N + 1) th matching region from the line buffer 510.

  The matching processing unit 850 is an example of an interpolation unit. When all pixel values of each pixel included in the matching region are stored in the matching processing buffer 520, matching processing is performed using pattern data prepared in advance, and interpolation is performed. The pixel value of the pixel is calculated. When the matching process is completed, the matching processing unit 850 notifies the readout control unit 840 and transmits the calculated pixel value of the interpolation pixel to the output control unit 860.

  The output control unit 860 is an example of an output control unit. When the pixel to be processed is not included in the matching region, the pixel value of the pixel to be processed transmitted from the read control unit 840 is output to the output buffer 530. Store.

  In addition, when the pixel to be processed is included in the matching region, the output control unit 860 has the pixel corresponding to the missing pixel stored in the matching processing buffer 520 at the position corresponding to the missing pixel. The pixel value of the transmitted interpolation pixel is inserted. Furthermore, the output control unit 860 stores the pixel value of each pixel into which the pixel value of the interpolation pixel is inserted in the output buffer 530 when it does not overlap with other matching regions. On the other hand, when the pixel overlaps with another matching region, the pixel value of a pixel other than the pixel corresponding to the overlap region among the pixels into which the pixel value of the interpolation pixel is inserted is stored in the output buffer 530.

<5. Flow of image processing>
Next, the flow of image processing by the image processing device 114 will be described. FIG. 9 is a flowchart showing a flow of image processing by the image processing device. When scanning by the reading device 116 is started, the image processing device 114 starts the flowchart shown in FIG. Here, the flow of image processing for image data for one line will be described.

  In step S901, the interpolation position information acquisition unit 810 acquires the interpolation position information and notifies the matching region determination unit 820.

  In step S902, the matching area determination unit 820 determines a matching area based on the interpolation position information. The matching area determination unit 820 inputs 1 to a matching area counter N that counts matching areas (an integer greater than or equal to 1 can be input to N).

  In step S <b> 903, the image data acquisition unit 830 starts processing for acquiring image data from the reading device 116 and storing it in the line buffer 510. Thereafter, the image data for one line is acquired, and the process is continued until the storage in the line buffer 510 is completed.

  In step S904, the read control unit 840 resets the read address.

  In step S905, the readout control unit 840 determines whether or not a readout destination pixel to be read based on the current readout address is included in the Nth matching region.

  If it is determined in step S905 that it is not included in the Nth matching region (No in step S905), the process proceeds to step S906. In step S906, the read control unit 840 accesses the line buffer 510 based on the current read address, reads the pixel value, and transmits the pixel value to the output control unit 860.

  In step S907, the output control unit 860 stores the transmitted pixel value in the output buffer 530.

  On the other hand, when it is determined in step S905 that it is included in the Nth matching region (in the case of Yes in step S905), the process proceeds to step S908. In step S908, the read control unit 840, the matching processing unit 850, and the output control unit 860 execute an interpolation process. Details of the interpolation processing will be described later.

  In step S909, the read control unit 840 determines whether the processing has been completed for the acquired image data. If it is determined in step S909 that the process has not been completed (No in step S909), the process proceeds to step S910.

  In step S910, the read control unit 840 increments the read address and returns to step S905.

  On the other hand, when it is determined in step S909 that the processing is completed (in the case of Yes in step S909), the image processing is ended.

<6. Details of interpolation processing>
Next, details of the interpolation processing (step S908 in FIG. 9) will be described. FIG. 10 is a flowchart showing the flow of the interpolation process.

  In step S1001, the read control unit 840 sets the start address of the addresses corresponding to each pixel included in the Nth matching region as the read address.

  In step S1002, the read control unit 840 accesses the line buffer 510 based on the read address set in step S1001, reads the pixel value of the corresponding pixel, and stores it in the buffer 520 for matching processing.

  In step S1003, the read control unit 840 determines whether or not the pixel values of all the pixels included in the Nth matching region have been stored in the matching processing buffer 520. If it is determined in step S1003 that there is a pixel value of a pixel that is not stored (in the case of No in step S1003), the process proceeds to step S1004.

  In step S1004, the read control unit 840 increments the read address and returns to step S1002.

  On the other hand, when it is determined in step S1003 that the pixel values of all the pixels have been stored in the matching processing buffer 520 (in the case of Yes in step S1003), the process proceeds to step S1005.

  In step S1005, the matching processing unit 850 uses the pixel values stored in the matching processing buffer 520 to perform matching processing using pattern data prepared in advance, and calculates the pixel value of the interpolation pixel.

  In step S1006, the output control unit 860 inserts the pixel value of the interpolation pixel at a position corresponding to the missing pixel in each pixel stored in the matching processing buffer 520.

  In step S <b> 1007, the output control unit 860 stores, in the output buffer 530, the pixel values of the pixels excluding the pixels in the overlapping area among the pixel values of each pixel into which the pixel value of the interpolation pixel is inserted. Note that the output control unit 860 stores each pixel into which the pixel value of the interpolation pixel is inserted in the output buffer 530 when there is no pixel in the overlapping region.

  In step S1008, the read control unit 840 increments the matching area counter N and returns to step S909 of FIG.

<7. Summary>
As is clear from the above description, the image processing device 114 according to the present embodiment is
Image data for one line in the main scanning direction generated based on the signal of each element of the reading device is acquired and stored in the line buffer.
The next pixel to be processed after the process of interpolating the Nth missing pixel is included in the (N + 1) th matching area based on the pixel value of each pixel included in the Nth matching area It is determined whether or not.
If it is determined that the pixel is included in the (N + 1) th matching area, the first address among the addresses corresponding to the pixels included in the (N + 1) th matching area is accessed for the line buffer. Then, the pixel value of each pixel included in the (N + 1) th matching region is sequentially read out.
The pixel value of the (N + 1) th interpolation pixel is calculated using the read pixel value.

  Thereby, according to the image processing device 114, whether the matching area overlaps with other matching areas or not, all the pixel values of each pixel included in the matching area are read out and stored in the matching processing buffer. be able to.

  As a result, according to the image processing device 114, the matching process can be appropriately performed regardless of whether the matching area overlaps with other matching areas or not, and the pixel value of the interpolation pixel can be calculated. .

[Second Embodiment]
In the first embodiment described above, the case where four pixels before and after the center of the missing pixel are determined as the matching region has been described. However, the method for determining the matching region is not limited to this. A predetermined number of pixels of 5 pixels or more before and after the missing pixel may be determined as the matching region. Further, the matching area may be determined by assigning different numbers of pixels before and after the missing pixel.

  In the first embodiment, the matching process is performed using predetermined pattern data. However, the matching process may be performed using different pattern data in accordance with the missing pixel.

  In the first embodiment, the case where the matching regions are overlapped by expanding the matching region has been described. For example, by reducing the length of each of the plurality of sensor chips 210_1 to 210_n, It is possible that there will be duplication. Even in such a case, according to the image processing device 114, the same interpolation processing as in the first embodiment can be applied.

  In the first embodiment described above, when the pixel value of the interpolation pixel is calculated, the pixel value is inserted at a position corresponding to the missing pixel. However, depending on the calculated pixel value, the pixel value is calculated at the position corresponding to the missing pixel. You may comprise so that it may not insert. Further, the insertion position may not be the position corresponding to the missing pixel, and may be configured to be switched for each document.

  In the first embodiment, the case where the image processing (FIG. 9 and the like) is executed using a dedicated integrated circuit has been described. However, the computer formed by the CPU, ROM, and RAM may be configured to execute the image processing (FIG. 9 and the like) by executing the image processing program.

  It should be noted that the present invention is not limited to the configuration shown here, such as a combination with other elements in the configuration described in the above embodiment. These points can be changed without departing from the spirit of the present invention, and can be appropriately determined according to the application form.

100: Image forming apparatus 110: Scanner unit 114: Image processing device 116: Reading devices 210_1 to 210_n: Sensor chip 220: Image data 230: Line sensor 240: Signal 250: Image data 301, 302, 303: Matching area 510: Line Buffers 511, 512, 513: Missing pixels 520: Buffers for matching processing 521, 522, 523: Pixel values of interpolation pixels 530: Output buffer 810: Interpolation position information acquisition unit 820: Matching region determination unit 830: Image data acquisition unit 840: Read control unit 850: Matching processing unit 860: Output control unit

JP 2013-093774 A

Claims (8)

Determining means for determining a pixel region used for calculating a pixel value of an interpolation pixel for interpolating a missing pixel in image data acquired for each line in the main scanning direction;
Of the image data, when the process of interpolating the Nth missing pixel is performed based on the pixel value of each pixel included in the Nth pixel area, the next pixel to be processed is ( Determination means for determining whether or not the pixel area is included in the (N + 1) th pixel region;
When it is determined that the pixel data is included in the (N + 1) th pixel area, an address corresponding to each pixel included in the (N + 1) th pixel area is stored in the memory storing the image data for one line. A read control means for accessing the head address of the pixels and sequentially reading out the pixel values of the pixels included in the (N + 1) th pixel area;
Interpolating means for interpolating the (N + 1) th missing pixel based on the pixel value of each pixel included in the (N + 1) th pixel area read by the readout control means, Image processing device.   The image processing device according to claim 1, wherein the interpolation unit calculates a pixel value of an interpolation pixel for interpolating the missing pixel by performing a matching process using different pattern data for each pixel region.   The pixel value of the (N + 1) -th interpolation pixel at the position corresponding to the (N + 1) -th missing pixel in each pixel included in the (N + 1) -th pixel area read by the readout control means. 3. The image processing device according to claim 1, further comprising: an output control unit configured to store an output buffer together with a pixel value of each pixel included in the (N + 1) th pixel region.   The output control means, the pixel value of the (N + 1) th interpolation pixel, together with the pixel value of the pixel excluding the pixels included in the overlapping area of the Nth pixel area and the (N + 1) th pixel area, The image processing device according to claim 3, wherein the image processing device is stored in the output buffer.   When it is determined that the pixel area is not included in the (N + 1) -th pixel area, the readout control unit has an address corresponding to the next pixel to be processed with respect to a memory storing the image data for one line. The image processing device according to claim 1, wherein the image processing device is accessed to read out a pixel value of the next pixel to be processed.   The image processing device according to claim 1, wherein the determination unit determines an area including a predetermined number of pixels centered on a position of the missing pixel as the pixel area. A determination step of determining a pixel region used for calculating a pixel value of an interpolation pixel for interpolating a missing pixel in image data acquired for each line in the main scanning direction;
Of the image data, when the process of interpolating the Nth missing pixel is performed based on the pixel value of each pixel included in the Nth pixel area, the next pixel to be processed is ( A determination step of determining whether or not the pixel region is included in the (N + 1) th pixel region;
When it is determined that the pixel data is included in the (N + 1) th pixel area, an address corresponding to each pixel included in the (N + 1) th pixel area is stored in the memory storing the image data for one line. A read control step of accessing a head address of the pixel area and sequentially reading out the pixel values of each pixel included in the (N + 1) th pixel area;
An interpolation step of interpolating the (N + 1) th missing pixel based on the pixel value of each pixel included in the (N + 1) th pixel region read in the readout control step. Image processing method. A determination step of determining a pixel region used for calculating a pixel value of an interpolation pixel for interpolating a missing pixel in image data acquired for each line in the main scanning direction;
Of the image data, when the process of interpolating the Nth missing pixel is performed based on the pixel value of each pixel included in the Nth pixel area, the next pixel to be processed is ( A determination step of determining whether or not the pixel region is included in the (N + 1) th pixel region;
When it is determined that the pixel data is included in the (N + 1) th pixel area, an address corresponding to each pixel included in the (N + 1) th pixel area is stored in the memory storing the image data for one line. A read control step of accessing a head address of the pixel area and sequentially reading out the pixel values of each pixel included in the (N + 1) th pixel area;
For causing the computer to execute an interpolation step of interpolating the (N + 1) th missing pixel based on the pixel value of each pixel included in the (N + 1) th pixel region read out in the readout control step. Image processing program.

Images