JP4448427B2 - Image processing device - Google Patents

Description

  The present invention relates to an image processing apparatus such as a digital copying machine.

  2. Description of the Related Art Conventionally, in an apparatus such as a digital copying machine that reads an image of a document and prints it on paper, as disclosed in, for example, Patent Document 1 and Patent Document 2, a combination of a plurality of line sensors There is one that can read an image of a large original by providing a wide line sensor.

  Each line sensor is arranged in parallel and staggered according to the design value, and the readable areas of the respective sensors partially overlap.

An image read by each line sensor generates one image by adjusting the range of the overlapping area reading area and the output timing of the delay circuit provided in the sensor on one line along the sub-scanning direction. To do.
JP 59-105762 A JP 60-31357 A

  In such an apparatus, it is difficult to completely match the actual value of the positional deviation along the reading direction of the original, that is, the so-called sub-scanning direction, of the attachment position of each line sensor with the above-described design value. Therefore, in order to generate a normal image without deviation along the sub-scanning direction, it is necessary to set the output timing by the delay circuit after grasping the actual value of the positional deviation along the sub-scanning direction. .

  In order to obtain such a positional deviation value, an image of a so-called adjustment document on which a lattice pattern or the like is printed is read, and the image read by each sensor is displayed on a monitor, and an operator visually checks the display screen. While performing the above, the images were overlapped to obtain a positional deviation value.

  As described above, the adjustment for generating a normal image by manual work requires considerable labor, and the cost for the process in the assembly increases. In addition, there is a problem in that the adjustment accuracy varies.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an image processing apparatus capable of easily generating a normal image of a document by a plurality of reading sensors provided in a state of being overlapped along the main scanning direction. .

That is, the image processing apparatus according to the present invention includes a plurality of sensors provided adjacent to each other so that a readable area for an original alternately overlaps along a main scanning direction which is a direction orthogonal to the reading direction of the original. Provided, when a linear image pattern printed on a document over a predetermined distance along the main scanning direction is read by the adjacent first and second sensors, the first sensor reads the linear image pattern. A composite image is generated by continuing the first image and the second image read by the second sensor along the main scanning direction, and an area corresponding to the first image in the generated image is generated . out of the region of the first sensor and the second central and a predetermined range before and after the overlapping region a region corresponding to portions of the sensor, among the pixels along the main scanning direction, pre The number of pixels that are more determined standard concentration, to calculate for each position along the sub-scanning direction, and the information of each position, the central and the reference in the area of the predetermined range before and after the first image Calculating a correspondence relationship with information on the number of pixels equal to or higher than the density, and each of the generated images along the main scanning direction of the center of the region corresponding to the second image and the region of the predetermined range before and after the center By calculating the number of pixels above the reference density among the pixels for each position along the sub-scanning direction, information on each position, the center of the second image , and the area in the predetermined range before and after the second image In the first image and the second image, the coordinate value of the position where the calculated number of pixels is associated is calculated in the other image. Towards the realm of To calculate the absolute value of the difference between the number of pixels for each coordinate value in the area of one image and the number of pixels for each coordinate value in the area of the other image. A variable amount of coordinate values that minimizes the sum of absolute values is determined, and based on the determined variable amount of coordinate values, a sensor that reads an image of a document first among the first and second sensors. It is characterized in that the time from the generation timing of the generated image to the synthesis timing of this image and an image generated by a sensor that reads a document image later among adjacent sensors is determined.

In the image processing apparatus according to the present invention, of the two sensors provided in parallel and in a staggered pattern, the first image read by the readable area of the adjacent first sensor and the second sensor can be read. An image in which the second image read by the region is continued along the main scanning direction is generated, and the first sensor and the second sensor in the region corresponding to the first image in the generated image are generated . The number of pixels that are equal to or higher than a predetermined reference density among the pixels along the main scanning direction in the region corresponding to the overlapping portion and in the center of the region and in a predetermined range before and after the region. by calculating for each position along the sub-scanning direction orthogonal to the direction, and information of each position, the central and the number of pixels of information in the above reference concentration in the region of the predetermined range before and after the first image To calculate the corresponding relationship between, also in the generated image, among the pixels along the main scanning direction of the area of the central and the predetermined range before and after the region corresponding to the second image, the reference density or By calculating the number of pixels in each position along the sub-scanning direction, information on each position and pixels that are equal to or higher than a reference density in the center of the second image and the predetermined range area before and after the second image The correspondence relationship with the information of the number is calculated, and the coordinate value of the position where the calculated number of pixels is associated in one image region of the first and second images is uniformly directed toward the other image region. The absolute value of the difference between the number of pixels for each coordinate value after the variable in one image area and the number of pixels for each coordinate value in the other image area is calculated. The position that minimizes the sum of the values The variable amount of the value is determined, and based on the determined variable amount of the coordinate value, the image and the image are generated from the generation timing of the image generated by the first sensor that reads the image of the document first. Since the time until the combination timing with the image generated by the sensor that reads the image of the document later among the adjacent sensors is determined, the normality of the document by the plurality of reading sensors provided in the overlapping state in the main scanning direction A simple image can be easily generated.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic front view showing a configuration example of an image reading apparatus according to an embodiment of the present invention.

  As shown in FIG. 1, the image reading apparatus 1 includes a first driving roller 4 and a second driving roller 5 with a reading unit 3 disposed below the document conveying path 2 interposed therebetween. A first driven roller 6 and a second driven roller 7 are disposed in a state of being pressed against the fourth driving roller 5 and the second driving roller 5, respectively.

  A drive belt 8 is bridged between the first drive roller 4 and the second drive roller 5. The drive belt 8 is further stretched over a tension roller 9 and is also spanned over a drive roller 11 attached to the rotation shaft of the drive motor 10.

  Accordingly, the first driving roller 4 and the second driving roller 5 are rotationally driven in the clockwise direction in FIG. 1 when the driving motor 10 rotates and the driving belt 8 is rotationally driven. The first driving roller 4 and the first driven roller 6 function as a first conveying unit, and the second driving roller 5 and the second driven roller 7 function as a second conveying unit.

  In the image reading apparatus 1, a white reference plate 12 for correcting shading distortion caused by the optical system is disposed on the side facing the reading unit 3 across the document conveyance path 2.

  In the image reading apparatus 1, the document table 13 is provided on the left side of the first driving roller 4 and the first driven roller 6 in FIG. 1, that is, at a position opposite to the direction toward the second driving roller 5. A document G to be read is placed on the document table 13.

  In the image reading apparatus 1, a document insertion detection sensor 14 is disposed on the left side (document table 13 side) of the first driven roller 6 in FIG. The document insertion detection sensor 14 detects the insertion (set) of the document G on the document table 13.

  In the image reading device 1, a document leading edge detection sensor 15 is disposed on the right side (reading unit 3 side) of the first drive roller 4 in FIG. 1. The document leading edge detection sensor 15 detects the leading edge of the document G conveyed from the document table 13 to the reading unit 3 by the first driving roller 4 and the first driven roller 6.

  In the image reading apparatus 1, the first driving roller 4 and the second driving roller 5 are rotationally driven by the driving motor 10 via the driving belt 8, and the document G placed on the document table 13 is transferred to the first driving roller 4. The first driven roller 6 conveys the image to the reading unit 3, and the reading unit 3 reads the image of the conveyed document G.

  The image reading apparatus 1 conveys the original G while reading the image of the original G by the reading unit 3, and conveys the original G after the image has been read by the second driving roller 5 and the second driven roller 7. The paper is discharged onto a paper discharge tray (not shown) outside the reading device 1.

  The reading unit 3 includes a first reading sensor unit 21 and a second reading sensor unit 22. Although the first reading sensor unit 21 and the second reading sensor unit 22 are not shown in detail, a light source, a selfoc lens, and a photoelectric conversion unit 23 (see FIG. 3) are housed in the case, respectively.

  The first reading sensor unit 21 is disposed on the upstream side in the conveyance direction of the document G, and reads a part of the image of the document G. The second reading sensor unit 22 is disposed downstream of the first reading sensor unit 21 in the conveyance direction of the document G, and reads the remaining image of the document G other than the image read by the first reading sensor unit 21.

  FIG. 2 is a top view showing an example of the configuration of the reading unit 3 of the image reading apparatus 1 according to the embodiment of the present invention.

  The upper surface of the reading unit 3 is covered with a glass 3a for placing a document. The first reading sensor unit 21 and the second reading sensor unit 22 provided below the glass 3a of the reading unit 3 include a plurality of sensors along the main scanning direction, that is, a direction orthogonal to the document conveyance direction. Is provided.

  Specifically, as shown in FIG. 2, the first reading sensor unit 21 includes sensors 21a, 21b, and 21c along the main scanning direction. The second reading sensor unit 22 includes sensors 22a and 22b along the main scanning direction.

  The sensors 21a, 21b, and 21c and the sensors 22a and 22b are parallel and staggered so that a readable area of the photoelectric conversion unit 23, that is, a part of the area where the document reflected light can be input overlaps in the main scanning direction. Is provided. The sensors 21a, 21b, 21c, 22a, and 22b are provided in the order of 21a, 22a, 21b, 22b, and 21c along the main scanning direction.

  The readable area of the photoelectric conversion unit 23 of the sensor 21a and the readable area of the photoelectric conversion unit 23 of the sensor 22a partially overlap along the main scanning direction. The readable area of the photoelectric conversion unit 23 of the sensor 22a and the readable area of the photoelectric conversion unit 23 of the sensor 21b partially overlap along the main scanning direction. The readable area of the photoelectric conversion unit 23 of the sensor 21b and the readable area of the photoelectric conversion unit 23 of the sensor 22b partially overlap along the main scanning direction. In addition, the readable area of the photoelectric conversion unit 23 of the sensor 22b and the readable area of the photoelectric conversion unit 23 of the sensor 21c partially overlap along the main scanning direction.

  Here, it has been described that the first reading sensor unit 21 and the second reading sensor unit 22 are provided with a total of five sensors. However, the other sensors are parallel and staggered so as to partially overlap in the main scanning direction. It may be provided in a shape.

  FIG. 3 is a block diagram showing a configuration of the image reading apparatus 1 according to the embodiment of the present invention.

  As shown in FIG. 3, the image reading apparatus 1 includes a control unit 31 that controls the processing operation of the entire apparatus. Further, the image of the document set on the image reading apparatus 1 is illuminated by a light (not shown). Light reflected by the original, that is, so-called original reflected light is irradiated to the photoelectric conversion units 23 of the sensors 21a, 21b, 21c, 22a, and 22b via optical systems (not shown) such as a folding mirror and a lens, respectively. . The control unit 31 is connected to the AD conversion unit 32, the shading correction unit 33, the image storage memory 34, the connection position deviation measurement unit 35, and the connection position correction unit 36, respectively. The A / D conversion unit 32 is connected to the photoelectric conversion unit 23 of each sensor.

  The photoelectric conversion unit 23 photoelectrically converts document reflected light by light irradiation. The AD conversion unit 32 AD converts the signal photoelectrically converted by the photoelectric conversion unit 23. The shading correction unit 33 performs shading correction on the A / D converted signal. The image storage memory 34 stores image data that has undergone shading correction.

  The connecting position deviation measuring unit 35 measures the positional deviation along the sub-scanning direction between adjacent sensors among the sensors 21a, 21b, 21c, 22a, and 22b based on the image data stored in the image storage memory 34. To do.

  Based on the measurement result of the joint position deviation measuring unit 35, the joint position correcting unit 36 generates an image by a sensor that reads an image of a document later from an image generation timing by a sensor that first reads the image of the document among adjacent sensors. Correct the time to timing. The meaning of this time will be described later.

  The image processing unit 37 performs various processes relating to reading of an image of a document such as image data correction and document recognition, and outputs an image of a print target image obtained as a result to a printing mechanism (not shown).

  FIG. 4 is a diagram showing an example of the adjustment document 41 set in the image reading apparatus according to the embodiment of the present invention.

  Unlike the normal document, the adjustment document 41 has a positional deviation (interval) along the sub-scanning direction, that is, the document reading direction, between the mounting positions of the first reading sensor unit 21 and the second reading sensor unit 22. A rectangular manuscript used for measurement. As shown in FIG. 4, a plurality of linear image patterns 42 along the main scanning direction are printed on the adjustment document 41. Here, eight linear image patterns 42 are printed on the adjustment document 41. The lines from the first line to the eighth line of the linear image pattern 42 are in a parallel relationship.

  Further, in the adjustment document 41, the leading edge margin portion (see FIG. 4) and the trailing edge margin portion (see FIG. 4) having a predetermined length in the sub-scanning direction are both print targets of the linear image pattern 42. It is an area that does not. This is because when the adjustment document 41 is transported, the transport speed of the leading margin portion and the trailing margin portion is not stable.

  The width of the linear image pattern 42, that is, the length along the sub-scanning direction of the band represented by the eight lines of the plurality of linear image patterns 42 corresponds to the outer peripheral length of the drive rollers 4 and 5. To do. Further, the number of the linear image patterns 42 may be such that the width is an integral multiple of the length of the outer peripheral length of the drive rollers 4 and 5. Accordingly, it is possible to suppress a decrease in image output accuracy due to uneven conveyance of the document, which is a phenomenon periodically generated by driving the drive rollers 4 and 5 due to the structure of the apparatus.

  Here, the length of the side of the adjustment document 41 along the main scanning direction is the same as the length of the outer edge along the main scanning direction of the glass 3 a that is the document placement portion of the reading unit 3. The length of the side of the adjustment document 41 along the sub-scanning direction is the same as the length of the outer edge of the glass 3a along the sub-scanning direction.

  The linear image pattern 42 printed on the adjustment document 41 is obtained when the adjustment document 41 in the adjustment document 41 is read by the reading unit 3 through driving of the first drive roller 4 and the second drive roller 5. The sensors 21a, 21b, 21c, 22a, and 22b are printed at locations facing the top of the photoelectric conversion unit 23.

  Further, the length of one line of the linear image pattern 42 along the sub-scanning direction exceeds the length of one pixel of an image obtained by reading the document by the reading device 1. As a result, it is possible to suppress a decrease in the accuracy of image output due to fine dirt and the like.

  Next, the operation of the image reading apparatus according to the embodiment of the present invention will be described.

  FIG. 5 is a flowchart showing the operation contents of the image reading apparatus according to the embodiment of the present invention.

  In the image reading apparatus 1 according to the embodiment of the present invention, first, according to a predetermined operation with respect to an input device (not shown), parameters relating to document conveyance and parameters relating to sensor connection portions are stored in the image storage memory 34 ( Step S1). The parameters relating to the document conveyance are determined by the sensors 22a and 22b based on the design value of the document conveyance speed, the design value of the deviation width of each sensor in the sub-scanning direction, and the generation timing of the image data by the sensors 21a, 21b, and 21c. This is an initial value of time (delay time) until image generation timing. This initial value is a value predicted that normal image output can be performed when the sensor is attached according to the above-described design value.

  FIG. 6 is a diagram illustrating an example of a sensor connection portion of the image reading apparatus 1 according to the embodiment of the present invention.

  Further, in the image reading device 1 according to the embodiment of the present invention, the parameters relating to the sensor connection portion are stored in the image storage memory 34 in accordance with a predetermined operation on an input device (not shown).

  The parameter relating to the sensor connection part is an element used as a reading effective element that is an element that actually photoelectrically converts the reflected light of the original document among the light receiving element group constituting the photoelectric conversion unit 23 of one of the adjacent sensors. , And a parameter for determining a terminal portion of an element used as a reading effective element in the light receiving element group constituting the photoelectric conversion unit 23 of the other sensor.

  The parameter relating to the sensor connection portion is a parameter for determining a reading effective element among all elements constituting the photoelectric conversion unit 23, and is set for each combination of sensors.

  For example, in the case where n light receiving elements constituting the photoelectric conversion unit 23 of the sensor 21a are arranged in the main scanning direction, and “a (<n)” as a parameter related to the sensor connection portion of the sensor 21a. "Is stored in the image storage memory 34, the control unit 31 of the light receiving element group arranged along the main scanning direction and constituting the photoelectric conversion unit 23 of the sensor 21a. Control is performed so that all the continuous elements from the first element to the a-th element on the side not intersecting with the light-receiving element are read effective elements, and the remaining elements are photoelectric conversion of reflected light of the document Control is performed so as to be an element that does not perform the above-described operation, a so-called read invalid element.

  Here, it is assumed that the control unit 31 stores “n” in the image storage memory 34 as a parameter relating to the sensor connection portion of the sensor 21a in accordance with the input of the number of dots by the input unit. In this case, the control unit 31 reads the elements from the first element to the nth element, which are the first elements farther from the sensor 22a, among the n light receiving element groups arranged in the sensor 21a as effective reading elements. Control to be.

  Further, assuming that “n” is stored in the image storage memory 34 as a parameter related to the sensor connection portion of the sensor 22a in accordance with the input of the number of dots by the input unit, the control unit 31 is arranged in the n number of sensors 22a. In the light receiving element group, when the first element closer to the sensor 21a is the first element, control is performed so that the first to nth elements are effective reading elements.

  Next, the image reading apparatus 1 causes the image of the adjustment document 41 to be read by each sensor of the reading unit 3 by driving the first driving roller 4 and the second driving roller 5.

  FIG. 7 is a diagram showing an example of a scan image of the adjustment document read by the image reading device according to the embodiment of the present invention.

  The control unit 31 (see FIG. 3) is generated by the image processing unit 37 through the image 51a generated through reading by the sensor 21a, the image 51b generated through reading by the sensor 22a, and the reading by the sensor 21b. The images 51a, 51b, 51c, 51d, and 51c are generated according to the positional relationship of each sensor based on the image 51c generated through the reading by the sensor 22b and the image 51d generated through the reading by the sensor 21c. Control is performed to generate a composite image 51 in which 51e is continued along the main scanning direction (step S2). The generated composite image 51 is stored in the image storage memory 34.

  Since the sensors 21a, 21b, and 21c read the image of the document at an earlier timing than the sensors 22a and 22b, the image 51a read by the sensor 21a, the image 51c read by the sensor 21b, and the image 51e read by the sensor 21c. Is earlier than the generation timing of the image 51b read by the sensor 22a and the image 51d read by the sensor 22b.

  After inputting the images 51a, 51c, and 51e, the image processing unit 37 holds these images for the delay time set in step S1, and holds the images 51b, 51d that are input after the delay time has passed, A composite image 51 is generated based on the images 51a, 51c, 51e.

  Here, since each sensor is provided in the order of the sensors 21a, 22a, 21b, 22b, and 21c along the main scanning direction, the images are arranged in the order of the images 51a, 51b, 51c, 51d, and 51e in the main scanning direction. The composite image 51 is generated by continuing along the line.

  Hereinafter, among the sensors, various processes for minimizing the positional deviation along the sub-scanning direction in the image of the print target image obtained by reading by the photoelectric conversion unit 23 of the sensor 21a and the sensor 22a will be described. Note that the above-described various processes relating to the two sensors in other combinations are the same as the various processes relating to the sensor 21a and the sensor 22a.

  FIG. 8 is a diagram showing an example of a scanning range for calculating the number of pixels along the main scanning direction in the scanned image generated by the image reading device according to the embodiment of the present invention.

  The scanning range for calculating the number of pixels along the main scanning direction in the image 51 is set as described above, the center of the connection portion of each sensor, and a predetermined length from this position in the main scanning direction. It is a range that is just around. The predetermined length of the scanning range is stored in advance in the image storage memory 34.

  FIG. 9 is a diagram illustrating a calculation example of the number of pixels along the main scanning direction in the scanned image generated by the image reading device according to the embodiment of the present invention.

  The control unit 31 controls the image processing unit 37 to scan the composite image 51 stored in the image storage memory 34. Then, the connecting position deviation measuring unit 35 performs sub-scanning on the total number of pixels (pixel values) in the main scanning direction that are equal to or higher than a predetermined reference density among the pixels included in the scanned image 51. Calculation is made for each predetermined distance along the direction (step S3).

  The predetermined distance along the sub-scanning direction is a distance corresponding to one pixel pitch expressed on the image 51 here. The reference density described above is a density corresponding to the density of the pixels appearing in the image 51 by reading the linear image pattern 42 printed on the adjustment document 41. Here, it is assumed that the density of the image printed on the document 41 is the same as the density of each pixel appearing in the image 51 by reading this image.

  Specifically, the connecting position deviation measuring unit 35 scans one line along the main scanning direction in the image 51a read by the sensor 21a that is the first sensor of the two adjacent sensors 21a and 22a. Then, the sum of the number of pixels having a density equal to or higher than the reference density among the pixels on one line is calculated. With this calculation, the number of pixels along the main scanning direction of the image 51a is calculated by reading the linear image pattern 42 printed on the document 41. FIG. 10 shows that the number of pixels on one line along the main scanning direction is 10 pixels.

  Then, the connecting position deviation measuring unit 35 calculates the sum of the number of pixels having a density equal to or higher than the reference density among the pixels on the line parallel to each other with an interval of one pixel from the above-described line in the sub-scanning direction. . Thereafter, the connecting position deviation measuring unit 35 repeats the above-described calculation for each line along the main scanning direction in the image 51a read by the sensor 21a.

  The calculation of the number of pixels described above is also performed on the image 51b read by the second sensor of the two adjacent sensors 21a and 22a, that is, the sensor 22a which is a sensor arranged in a staggered manner in parallel with the sensor 21a. .

  FIG. 10 is a diagram illustrating an example of a graph of the calculation result of the number of pixels along the main scanning direction with respect to the position in the sub-scanning direction by the image reading device according to the embodiment of the present invention.

  As described above, the connecting position deviation measuring unit 35 calculates the sum of the number of images in the image 51a that is equal to or higher than the reference density along the main scanning direction at every predetermined distance along the sub-scanning direction. Thus, the correspondence relationship between the information on each position in the sub-scanning direction in the image 51a and the total number of pixels that are equal to or higher than the reference density along the main scanning direction is calculated.

  This calculation of the correspondence relationship is also performed on the correspondence relationship between the information on each position in the sub-scanning direction in the image 51b and the total number of pixels having a density equal to or higher than the reference density. The graph shown in FIG. 10 is drawn based on these calculated correspondences.

  The reference position of the coordinate value of the position in the sub-scanning direction in the correspondence relationship calculated for the image 51b is the same as the reference position of the coordinate value of the position in the sub-scanning direction in the correspondence relationship calculated for the image 51a.

  The dotted protrusion 61 in the graph shown in FIG. 10 is a portion indicating the number of pixels equal to or higher than the reference density for each line parallel to the main scanning direction of the linear image pattern 42 included in the image 51a. Also, the solid line protruding portion 62 of the graph shown in FIG. 10 is a portion indicating the number of pixels equal to or higher than the reference density for each line parallel to the main scanning direction of the linear image pattern 42 included in the image 51b.

  The connecting position deviation measuring unit 35 includes the value of the number of pixels indicated in association with the coordinate value information of one position in one of the two types of correspondence described above and the information on the other correspondence. The absolute value of the difference from the value of the number of pixels indicated in association with the coordinate value information at the same position as the one position described above is calculated.

  This calculation is performed for each position in the sub-scanning direction. The connecting position deviation measuring unit 35 obtains a value obtained by accumulatively adding the calculated absolute values, that is, the sum of the absolute values of the differences (overlap point) (step S4). At this time, the connecting position deviation measuring unit 35 associates the value of the variable amount with the value of the overlap point calculated when the update process using the variable amount is performed, and associates this information with the image storage memory 34 or other information. Is stored in a memory (not shown).

  Then, the connection position deviation measurement unit 35 uniformly adds the coordinate value of the position to which the number of pixels is associated in the correspondence information calculated for the image 51a, for example, a value corresponding to the length of one pixel as a variable amount. By doing so, the correspondence information is updated.

  Further, the correspondence information calculated for the image 51a is left as it is, and the coordinate value of the position to which the number of pixels is associated in the correspondence information calculated for the image 51b is uniformly subtracted by the above-described variable amount, thereby The relationship may be updated.

  Then, the connecting position deviation measuring unit 35 changes the variable amount of the coordinate value of the position in the correspondence updating process by a value corresponding to, for example, one pixel pitch, and repeatedly performs the same process as the process of step S4 described above ( Step S5).

  The joining position deviation measuring unit 35 compares the values of the overlapping points calculated by the processes of steps S4 and S5, and determines the minimum value among these calculated overlapping points. Then, the connecting position deviation measuring unit 35 determines the minimum value based on the information on the correspondence between the value of the variable amount described above and the value of the overlap point calculated when the update process using the variable amount is performed. An amount associated with the determined overlap point value, that is, a variable amount of the coordinate value of the position is derived (step S6).

  FIG. 11 is a diagram showing an example of a graph showing the relationship between the overlapping point with respect to the relative position in the sub-scanning direction and the relative position in the sub-scanning direction, by the image reading apparatus 1 according to the embodiment of the present invention.

  The graph shown in FIG. 11 is used to calculate the overlap point value calculated by the processes of steps S4 and S5 and the set value of the relative position of the photoelectric conversion unit 23 of the sensors 21a and 22a in the sub-scanning direction, that is, the overlap point. It is the graph drawn based on the relationship with the variable amount of the coordinate value of the position which was set. In the relationship shown in this graph, the value of the relative position where the overlapping point is minimum corresponds to an approximate value of the interval along the sub-scanning direction of the photoelectric conversion unit 23 of the sensors 21a and 22a. The variable amount at the reference position in FIG.

  Next, the splicing position correction unit 36 sets a delay time for generating an image of the print target image as the sensors 21a and 22a read based on the variable amount derived in the process of step S6 (step S6). S7).

  Specifically, the joint position correction unit 36 is a variable amount derived in the process of step S6, that is, a dot indicating the interval along the sub-scanning direction of the photoelectric conversion unit 23 of the sensor 21a and the photoelectric conversion unit 23 of the sensor 22a. When the approximate value of the number is obtained, the distance of the interval described above is obtained based on the number of dots. Based on the distance value and the design value (constant value) of the document transport speed that accompanies the driving of the first drive roller 4 and the second drive roller 5, the joint position correction unit 36 uses the sensor 21 a. A holding time until an image of a normal print target image is generated, that is, a delay time, is calculated for the image generated by the reading by.

  After performing such processing, when the image processing unit 37 generates an image of the print target image based on the images generated by the plurality of sensors described above, the sub-image in this image is displayed. The deviation value along the scanning direction is minimized.

  As described above, in the image reading apparatus according to the embodiment of the present invention, when the original reading sensors are arranged in parallel and staggered, the adjustment original 41 on which the linear image pattern 42 is printed, The number of pixels along the main scanning direction of the image obtained by reading with the adjacent sensor is calculated for each position along the sub-scanning direction, and using this calculation result, the number of pixels along the sub-scanning direction of the adjacent sensor is calculated. An approximate value of the deviation value is calculated, and based on the calculation result, an image generated by a sensor that reads an original image first among adjacent sensors, and a sensor that reads an original image later among adjacent sensors Since the delay time required for the synthesis with the image generated by the above is determined, an image in which the shift along the sub-scanning direction is minimized without the need for visual inspection or complicated operation by the operator. It can be set to output.

  In the process of step S3 described above, the image 51 is scanned and the sum of the number of pixels along the main scanning direction that is equal to or higher than a predetermined reference density is calculated. Based on this shading, for example, density values expressed in 256 levels with black as “255” and white as “0” are calculated for each pixel along the main scanning direction, and these are calculated. A value obtained by accumulating these density values, that is, a cumulative value of density values of pixels along the main scanning direction may be calculated.

  When this density value is calculated, in the processing after step S4 described above, “the accumulated value of the density values of each pixel” is used instead of “the total number of pixels having a density equal to or higher than the reference density”. The process described above may be performed.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Moreover, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be omitted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

1 is a schematic front view showing a configuration example of an image reading apparatus according to an embodiment of the present invention. FIG. 3 is a top view illustrating an example of a configuration of a reading unit of the image reading device according to the embodiment of the present invention. 1 is a block diagram showing a configuration of an image reading device according to an embodiment of the present invention. FIG. 4 is a diagram showing an example of an adjustment document set in the image reading apparatus according to the embodiment of the present invention. 5 is a flowchart showing the operation content of the image reading apparatus according to the embodiment of the present invention. The figure which shows an example of the sensor connection part of the image reading apparatus according to embodiment of this invention. FIG. 5 is a diagram showing an example of a scan image of an adjustment document read by an image reading device according to an embodiment of the present invention. The figure which shows an example of the scanning range for calculation of the pixel count along the main scanning direction in the scanning image produced | generated by the image reading apparatus according to embodiment of this invention. The figure which shows the example of calculation of the pixel count along the main scanning direction in the scanning image produced | generated by the image reading apparatus according to embodiment of this invention. The figure which shows an example of the graph of the calculation result of the pixel count along the main scanning direction with respect to the position of a subscanning direction by the image reading apparatus according to embodiment of this invention. The figure which shows an example of the graph which shows the relationship between the overlap point with respect to the relative position of a subscanning direction, and the relative position of a subscanning direction by the image reading apparatus according to embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Image reading apparatus, 2 ... Original conveyance path, 3 ... Reading part, 3a ... Glass, 4 ... 1st drive roller, 5 ... 2nd drive roller, 6 ... 1st driven roller, 7 ... 2nd driven roller, 8 DESCRIPTION OF SYMBOLS ... Drive belt, 9 ... Tension roller, 10 ... Drive motor, 11 ... Drive roller, 12 ... White reference board, 13 ... Document table, 14 ... Document insertion detection sensor, 15 ... Document leading edge detection sensor, 21 ... First reading sensor 21a, 21b, 21c, 22a, 22b ... sensor, 22 ... second reading sensor unit, 23 ... photoelectric conversion unit, 31 ... control unit, 32 ... AD conversion unit, 33 ... shading correction unit, 34 ... image storage memory 35... Linkage position deviation measuring unit 36... Linkage position correcting unit 41... Adjustment document, 42. Linear image pattern, 51.

Claims (5)

A plurality of sensors provided adjacent to each other so that a readable area for a document alternately overlaps along a main scanning direction which is a direction orthogonal to a reading direction of the document;
When a linear image pattern of a predetermined length along the main scanning direction printed on a document is read by the adjacent first and second sensors among the sensors, the linear image pattern is read by the first sensor. Image generating means for generating a composite image in which the first image and the second image read by the second sensor are continuous in the main scanning direction;
In the generated image, the region corresponding to the overlapping portion of the first sensor and the second sensor in the region corresponding to the first image, and the region in the center of the region and a predetermined range before and after the region Of the pixels along the main scanning direction, the number of pixels that are equal to or higher than a predetermined reference density is calculated for each position along the sub-scanning direction. Means for calculating a correspondence relationship between information and information on the number of pixels equal to or higher than the reference density in the center of the first image and the region of the predetermined range around the center ;
The number of pixels in the generated image that are equal to or higher than the reference density among the pixels along the main scanning direction of the center and the region in the predetermined range before and after the center in the region corresponding to the second image. Is calculated for each position along the sub-scanning direction, so that information on each position on the generated image and the reference density in the center of the second image and the predetermined range area before and after the second image are calculated. Means for calculating the correspondence with the information on the number of pixels as described above;
Variable means for uniformly changing the coordinate value of the position corresponding to the calculated number of pixels in the area of one of the first and second images toward the area of the other image;
Difference calculating means for calculating an absolute value of a difference between each number of pixels for each coordinate value after the variable in the area of the one image and each pixel value for each of the coordinate values in the area of the other image;
Discriminating means for discriminating a variable amount of the coordinate value by the variable means so that the total sum of the calculated absolute values is minimized;
Based on the variable amount of the determined coordinate value, from the generation timing of the image generated by the sensor that first reads the image of the original document among the first and second sensors, this image and the adjacent sensor are detected. An image processing apparatus comprising: means for determining a time until a synthesis timing of the original image and an image generated by a sensor that reads the original later.   The image processing apparatus according to claim 1, wherein a length of the linear image pattern printed on the document along a sub-scanning direction exceeds a length of a single pixel of the generated image. There are a plurality of linear image patterns printed on the original,
2. The image processing according to claim 1, wherein a length of the plurality of linear image images along the sub-scanning direction is an integral multiple of an outer peripheral length of a roller for conveying the document. apparatus. Means for storing image information of a document having the linear image pattern;
The image processing apparatus according to claim 1, further comprising: a printing unit that prints out an original including the linear image pattern based on the stored image information. A plurality of sensors provided adjacent to each other so that a readable area for a document alternately overlaps in a main scanning direction which is a direction perpendicular to the reading direction of the document;
When a linear image pattern of a predetermined length along the main scanning direction printed on a document is read by the adjacent first and second sensors among the sensors, the linear image pattern is read by the first sensor. Image generating means for generating a composite image in which the first image and the second image read by the second sensor are continuous in the main scanning direction;
In the generated image, the region corresponding to the overlapping portion of the first sensor and the second sensor in the region corresponding to the first image, and the region in the center of the region and a predetermined range before and after the region The cumulative value of the value indicating the density of each pixel along the main scanning direction is calculated for each position along the sub-scanning direction, so that the information on each position on the generated image and the first Means for calculating a correspondence relationship between information on accumulated values of density values in the center of the image of the image and a region of the predetermined range before and after the center ;
In the generated image, a cumulative value of values indicating the density of each pixel along the main scanning direction in the center of the region corresponding to the second image and the region in the predetermined range before and after the center is subscanned. By calculating for each position along the direction, the correspondence relationship between the information on each position on the generated image and the information on the accumulated value in the image in the second center and the region in the predetermined range before and after the center. A means of calculating
Variable means for uniformly changing the coordinate value of the position corresponding to the calculated cumulative value in the area of one of the first and second images toward the other image area;
A difference calculating means for calculating an absolute value of a difference between each accumulated value for each coordinate value after the variable in the one image area and each accumulated value for each coordinate value in the area of the other image;
A discriminating means for discriminating a variable amount of the coordinate value by the variable means so that a sum of absolute values of the calculated differences is minimized;
And a means for determining each of the first sensor reading effective area and the reading invalid area and the reading effective area and the reading invalid area of the second sensor based on the determined variable value of the coordinate value. An image processing apparatus.

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