JP2012204990A - Image scanner apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image scanner apparatus for generating image data in which brightness in a margin part on a paper surface is maintained at a constant level.SOLUTION: In a passbook handling apparatus 1 which is an image scanner apparatus, storage means 80 stores multiple line image data output from a linear image sensor 23. Further, image processing means 90 corrects each of the multiple line image data stored in the storage means 80 so that gradation values of the brightest pixels included in the respective multiple line image data correspond to each other based on the multiple line image data stored in the storage means 80. The corrected multiple line image data is stored in the storage means 80.

Description

  The present invention relates to an image scanner device.

  2. Description of the Related Art Conventionally, as a reading method of a commercial image scanner apparatus having a linear image sensor, a method of imaging a medium while keeping the brightness of a margin part of the medium to be read constant is known. Such a reading method (hereinafter referred to as a white reference tracking method) is disclosed in, for example, Patent Document 1 and is widely used in fields such as OCR.

  An image scanner that employs a white reference tracking method feeds back line image data of a medium output from a linear image sensor and adjusts the output of the sensor as needed, thereby adjusting the brightness of the margin included in each line image data. Can be kept constant.

  Such a white reference tracking method is also adopted in an automatic transaction apparatus or a passbook entry machine that reads a passbook.

JP-A-6-178105

  By the way, as illustrated in FIG. 1, a booklet medium such as a passbook 100 is another medium in that a binding portion (hereinafter referred to as a center fold) 102 exists in addition to a wrinkle 101 generated on a paper surface. Is different.

  The center fold 102 greatly affects the brightness of the margin included in the line image data. Specifically, as illustrated in FIG. 2, the center fold 102 has a large curvature radius in the vicinity of the base 102 </ b> A. In 102B, since the radius of curvature is small, the brightness of the margin is rapidly changed. It is difficult to follow such a rapid change in brightness by adjusting the sensor output by a simple moving average calculated by feedback control.

  For this reason, in an automatic transaction apparatus and a passbook bookkeeping machine that are image scanner apparatuses, a brightness adjustment coefficient (hereinafter simply referred to as an adjustment coefficient) according to a sub-scanning position obtained through a test or the like performed in advance is fed back. A method is employed in which the brightness of the margin is kept constant by following the sudden brightness change caused by the centerfold of the passbook.

  However, the adjustment coefficient calculated through such a test or the like strongly depends on the configuration of the device. For this reason, when a device having a different configuration is newly designed, it is necessary to perform a new test and recalculate the adjustment coefficient.

  In addition, the adjustment coefficient should be adjusted in consideration of individual differences, and is not equally applicable to all devices even if they are devices of the same model. For this reason, even when an adjustment coefficient obtained by a test or the like is used, the brightness of the margin cannot always be kept constant in all devices of the same model.

  Further, the adjustment coefficient depends not only on the device but also on the passbook to be read. The shape of the center fold changes day by day depending on usage and aging. For this reason, even when an adjustment coefficient that takes into account individual differences among devices is used, the brightness of the margin cannot always be maintained constant.

  In the above, the booklet medium such as a passbook is used as an example to explain the difficulty of maintaining the brightness of the margin in a medium whose brightness changes rapidly. Similarly, when the brightness changes rapidly, it is difficult to maintain the brightness of the margin.

  In view of such circumstances, an object of the present invention is to provide an image scanner device that generates image data in which the brightness of a blank portion of a paper surface is maintained constant.

  One aspect of the present invention is an image scanner device that reads an optical image of an object, and includes a plurality of photoelectric conversion elements arranged linearly, and a linear image sensor that outputs line image data of the object; Transport means for transporting the object in a sub-scanning direction orthogonal to the main scanning direction of the linear image sensor, and each output from the linear image sensor at each position where the object is transported in the sub-scanning direction. A plurality of the line image data stored in the storage means so that the gradation values of the brightest pixels included in each of the plurality of line image data coincide with each other. An image processing for correcting each of the plurality of line image data stored in the storage unit based on the line image data. It provides an image scanner which includes a means.

  Another aspect of the present invention is an image scanner device that reads an optical image of an object, and includes a plurality of photoelectric conversion elements arranged linearly, and outputs a line image data of the object And a conveying means for conveying the object in a sub-scanning direction orthogonal to the main scanning direction of the linear image sensor, and the linear image sensor output at each position where the object is conveyed in the sub-scanning direction. A main scanning direction correction unit that performs shading correction on the line image data based on white reference line master data, the white reference line master data, and the plurality of line image data output from the main scanning direction correction unit; And a gradation value of the brightest pixel included in each of the plurality of line image data Image processing means for correcting each of the plurality of line image data stored in the storage means based on the plurality of line image data stored in the storage means so as to match each other. An image scanner device is provided.

  According to the present invention, it is possible to provide an image scanner device that generates image data in which the brightness of the margin portion of the paper is maintained constant.

It is a figure which shows the shape of a bankbook. It is a figure for demonstrating the centerfold of a passbook. It is a schematic block diagram of the bankbook handling apparatus which concerns on a present Example. It is a functional block diagram of the bankbook handling apparatus concerning a present Example. It is the figure illustrated about the state of the paper surface of a passbook. FIG. 6 is a diagram illustrating the gradation distribution of white reference line master data used in the bankbook handling apparatus according to the embodiment and the gradation distribution of line image data of the line L illustrated in FIG. 5 output from the linear image sensor. is there. FIG. 5 is a diagram schematically showing a gradation distribution obtained from a plurality of line image data output from a main scanning direction correction unit exemplified in FIG. 4.

  FIG. 3 is a schematic configuration diagram of a bankbook handling apparatus according to the present embodiment. FIG. 4 is a functional block diagram of the bankbook handling apparatus according to the present embodiment. The bankbook handling apparatus 1 illustrated in FIGS. 3 and 4 is an apparatus that performs cash processing and bankbook bookkeeping processing, and is an image scanner device that reads an optical image of the paper surface of the bankbook 100.

  As illustrated in FIG. 3, the bankbook handling apparatus 1 includes a plurality of conveyance rollers (conveyance rollers 2 a, 2 b, 3 a, 3 b, which are conveyance means for conveying the bankbook 100 to a conveyance path 2 where the bankbook 100 is conveyed. 4a, 4b, 5a, 5b), a magnetic stripe reading unit 10 that reads the magnetic stripe of the passbook 100, a scanner unit 20 that scans the paper surface of the passbook 100 and outputs image data for each line (line image data), A printing unit 30 for printing transaction information on the paper surface of the passbook 100, a page turning unit 40 for turning the pages of the passbook 100, a turn unit 50 for inverting the passbook 100, and a collection for collecting the passbook 100 when an error occurs. And the insertion portion 60. The bankbook handling apparatus 1 further includes an A / D converter 70, a storage unit 80, and an image processing unit 90.

  The scanner unit 20 includes a light source 21 that emits illumination light with a constant output, an optical system that includes a mirror 22, and a linear image sensor 23 that includes a plurality of photoelectric conversion elements arranged linearly. The main scanning direction, which is the arrangement direction of the photoelectric conversion elements of the linear image sensor 23, is orthogonal to the conveyance direction of the bankbook 100. In other words, in the bankbook handling apparatus 1, the transport means composed of a plurality of transport rollers is configured to transport the bankbook 100 in a direction (sub-scanning direction) orthogonal to the main scanning direction.

  The bankbook 100 inserted into the bankbook handling apparatus 1 is conveyed by a plurality of conveyance rollers, and after the information is read from the magnetic stripe by the magnetic stripe reading unit 10, it passes below the scanner unit 20. At that time, the scanner unit 20 irradiates the book 100 with illumination light emitted from the light source 21, and the reflected light is detected by the linear image sensor 23 through an optical system such as a mirror 22. By performing this at each conveyance position (sub-scanning position), the line image data of the passbook 100 at each conveyance position (sub-scanning position) is output from the linear image sensor 23. As a result, all the line image data of the passbook 100 is output. Is output.

  The line image data output from the scanner unit 20 is converted into a digital signal by the A / D converter 70 and then recorded in the storage unit 80. The image processing unit 90 corrects each of the plurality of line image data stored in the storage unit 80 based on the plurality of line image data stored in the storage unit 80. More specifically, the image processing unit 90 stores the brightest pixel included in each of the plurality of line image data, that is, the pixel corresponding to the margin part, in the storage unit 80 so that the gradation values match each other. Each of the plurality of line image data stored in the storage means 80 is corrected based on the stored plurality of line image data. As a result, image data of the entire paper surface of the passbook 100 in which the brightness of the margin is kept constant is generated.

  The image data with the corrected brightness generated by the image processing means 90 is used for various check processes for the passbook 100. When it is determined that the result of the check is normal, the transaction is continued and printing processing by the printing unit 30 is performed. On the other hand, when the result of the check is determined to be abnormal, the passbook 100 is determined. The transaction is terminated by returning the bankbook 100 or collecting the passbook 100 to the capturing unit 60.

Next, the processing from when the line image data is output from the linear image sensor 23 until the image data is generated by the image processing means 90 will be described in detail.
As illustrated in FIG. 4, the storage unit 80 of the bankbook handling apparatus 1 includes a memory 81, a memory read controller 82 for reading data from the memory 81, and a memory write controller 83 for writing data to the memory 81. I have.

  The memory 81 stores line image data output from the linear image sensor 23 and image data after brightness correction generated by the image processing means 90. The memory 81 stores white reference line master data to be described later.

  As illustrated in FIG. 4, the image processing unit 90 of the bankbook handling apparatus 1 includes a main scanning direction correction unit 91 that performs shading correction on each of the plurality of line image data stored in the storage unit 80, and main scanning. A white reference calculation unit 92 that calculates a white reference gradation value from a plurality of line image data corrected by the direction correction unit 91, and a white reference calculation unit 92 determines a gradation value of each margin portion of the plurality of line image data. And a sub-scanning direction correcting unit 95 that corrects each of the plurality of line image data corrected by the main scanning direction correcting unit 91 so as to coincide with the calculated white reference gradation value. The white reference calculation unit 92 further includes a line peak extraction unit 93 and a white reference determination unit 94.

  The line image data output from the linear image sensor 23 is converted into a digital signal by the A / D converter 70 and then stored in the memory 81 via the memory write controller 83. When the passbook 100 passes through the scanner unit 20 and all line image data of the passbook 100 is stored in the memory 81, the memory read controller 82 sequentially reads the plurality of line image data stored in the memory 81. And transmitted to the main scanning direction correction means 91.

  In the bankbook handling apparatus 1, for example, even when the entire white paper is read by the scanner unit 20, due to uneven illumination or vignetting in the optical system, each photoelectric conversion element of the linear image sensor 23 is used. The amount of incident light is not always constant. Therefore, if the white brightness reference is set to be constant regardless of the pixel, the actual brightness of the paper cannot be correctly evaluated.

  Therefore, in the passbook handling apparatus 1, the main scanning direction correction unit 91 performs shading correction on the line image data received via the memory read controller 82. For the shading correction, white reference line master data stored in advance in the memory 81 is used. The white reference line master data is data obtained by a test or the like performed in advance, and is data indicating a gradation value serving as a reference for white brightness for each pixel in the main scanning direction.

  FIG. 5 is a diagram illustrating the state of the paper surface of the passbook. The shading correction by the main scanning direction correction unit 91 will be briefly described by taking the case where the line L of the bankbook 100 illustrated in FIG. 5 is read as an example.

  6 shows the gradation distribution of the white reference line master data used in the bankbook handling apparatus according to the present embodiment, and the gradation distribution of the line image data of the line L illustrated in FIG. 5 output from the linear image sensor. Is illustrated.

  The gradation distribution (solid line) of the white reference line master data illustrated in FIG. 6 has a concave shape in which the gradation at both ends is lower than the gradation at the center. The main factor that the gradation distribution of the white reference line master data becomes concave is that the light source 21 is linear like the linear image sensor 23, and therefore the illuminance at both ends tends to be insufficient. . On the other hand, the tone distribution (broken line) of the line image data illustrated in FIG. 6 shows a shape that is approximately the same as that of the white reference line master data, but peaks occur at two locations indicated by the positions P3 and P4. ing. These peaks correspond to two print portions (print portion 103 and print portion 104) on line L of bankbook 100 illustrated in FIG. That is, the peak generated at the position P3 corresponds to the print portion 103, and the peak generated at the position P4 corresponds to the print portion 104.

The shading correction by the main scanning direction correcting unit 91 is performed by converting the gradation value of each pixel of the line image data into the gradation value obtained by the following calculation formula based on the white reference line master data. . Here, [] indicates a Gaussian symbol.
Tone value after correction = [(number of tones) × (tone value before correction / tone value of white line master data)]

Assuming that the number of gradations of the image data generated by the passbook handling apparatus 1 is 255, the gradation values after correction by the main scanning direction correction means 91 for the pixels at the positions P1, P2, P3 and P4 of the line image data are It becomes as follows.
Tone value after correction of the pixel at position P1 234 = [255 × 80/87]
Tone value after correction of the pixel at position P2 216 = [255 × 97/114]
Tone value after correction of the pixel at position P3 52 = [255 × 23/112]
Tone value after correction of the pixel at position P4 39 = [255 × 19/124]

  In this way, by correcting the gradation value using the white line master data, it is possible to obtain line image data in which the influence of uneven illumination and vignetting in the optical system is suppressed. The line image data output from the main scanning direction correction unit 91 is not adjusted for the brightness between lines. For this reason, as illustrated in FIG. 7, the uneven brightness that is caused mainly by the bankbook 100 side such as the wrinkle 101 and the center fold 102 has not been eliminated. FIG. 7 is a diagram schematically showing a gradation distribution obtained from a plurality of line image data output from the main scanning direction correction unit 91. In FIG. 7, the gradation distribution in the main scanning direction is drawn as a constant gradation distribution in order to simplify the illustration.

The line image data corrected by the main scanning direction correcting unit 91 is transmitted to the line peak extracting unit 93 and the sub scanning direction correcting unit 95 as shown in FIG.
Each time the line peak extraction unit 93 receives the line image data output from the main scanning direction correction unit 91, the line peak extraction unit 93 determines the brightest pixel included in the line image data corrected by the main scanning direction correction unit 91 as the line peak pixel. And output to the white reference determining means 94. Note that the line peak pixels extracted here correspond to the pixels in the blank portion of each line image data.

  When the white reference determining unit 94 receives the line peak pixel information of all the lines from the line peak extracting unit 93, the white reference determining unit 94 determines the tone value of the brightest pixel among the line peak pixels as the white reference tone value, Output to the sub-scanning direction correcting means 95.

  When the sub-scanning direction correcting means 95 receives the white reference gradation value from the white reference determining means 94, each of the line image data output from the main scanning direction correcting means 91 has a gradation value of the line peak pixel of white. Correction is made so as to match the reference gradation value. More specifically, the gradation value of each pixel of the line image data is multiplied by the ratio of the white reference gradation value to the gradation value of the line peak pixel (white reference gradation value / line peak pixel gradation value). Thus, the line image data is normalized. For example, if the white reference gradation value calculated by the white reference determining means 94 is 250, line image data with a line peak pixel gradation value of 200 is converted by the sub-scanning direction correcting means 95 into each pixel. The gradation value is converted to a gradation value of 1.25 (= 250/200) times.

In this way, the sub-scanning direction correcting unit 95 corrects the line image data of all lines based on the white reference gradation value, thereby changing the gradation value of the line peak pixel of the line image data of all lines to the white reference. It is possible to match the gradation value. As a result, it is possible to generate image data in which the blank portion of the line image data of all lines matches the white reference gradation value.
The line image data corrected by the sub-scanning direction correcting unit 95 is stored in the memory 81 via the memory read controller 82.

  As described above, according to the bankbook handling apparatus 1 according to the present embodiment, the blank portion of the line image data of all lines can be matched with the white reference gradation value, so that the brightness of the blank portion of the paper surface is maintained constant. Image data can be generated. As a result, it is possible to clearly observe even an area where the center fold or wrinkle of the passbook is generated.

  Further, in the bankbook handling apparatus 1 according to the present embodiment, it is necessary to prepare in advance at least one line of white reference line master data, but it is not necessary to prepare data for each sub-scanning position. For this reason, the burden concerning prior preparation can be minimized.

  Furthermore, the passbook handling apparatus 1 according to the present embodiment can correct the brightness without using parameters that depend on the medium. For this reason, it is possible to always generate image data in which the brightness of the blank portion of the paper surface of the medium is constant regardless of the degree of deterioration or shape of the medium.

In addition, this invention is not limited to the Example mentioned above, A various deformation | transformation can be implemented unless it is contrary to the meaning.
For example, in the bankbook handling apparatus 1 according to the present embodiment, an example is shown in which the white base gradation value is determined as the gradation value of the brightest pixel among the line peak pixels of all lines. It is not limited to the brightest line peak pixel.

  In this embodiment, as illustrated in FIG. 4, the shading correction by the main scanning direction correction unit 91 is performed on the line image data temporarily stored in the memory 81, but by the A / D converter 70. It may be performed immediately after conversion to a digital signal. That is, the memory 81 may store line image data after shading correction.

  Further, in the present embodiment, as illustrated in FIG. 4, an example in which the memory 81 is included in the storage unit 80 is shown, but the configuration of the storage unit 80 is not particularly limited to this configuration. For example, the storage unit 80 may include a plurality of memories, of which a volatile memory may store line image data, and a nonvolatile memory may store image data and white reference line master data. Further, the storage unit 80 may include a hard disk device instead of or in addition to the memory.

  Further, in this embodiment, for simplification of description, after all line image data of the passbook 100 output from the linear image sensor 23 is stored in the memory 81, image processing is started by the image processing means 90. An example is described. However, the start of processing by the image processing unit 90 is not limited to after all line image data is stored. In order to shorten the time of the image generation processing, the processing by the image processing means 90 may be started before the memory 81 finishes storing all the line image data.

DESCRIPTION OF SYMBOLS 1 Passbook handling apparatus 2 Conveyance path 2a, 2b, 3a, 3b, 4a, 4b, 5a, 5b, 6a, 6b Conveyance roller 10 Magnetic stripe reading part 20 Scanner part 21 Light source 22 Mirror 23 Linear image sensor 30 Printing part 40 Page turning Section 50 Turn section 60 Capture section 70 A / D converter 80 Storage means 81 Memory 82 Memory read controller 83 Memory write controller 90 Image processing means 91 Main scanning direction correction means 92 White reference calculation means 93 Line peak extraction means 94 White reference determination Means 95 Sub-scanning direction correcting means 100 Passbook 101 Wrinkle 102 Center fold 102A Near skirt 102B Near center 103, 104 Printed portion L line P1, P2, P3, P4 position

Claims (5)

An image scanner device for reading an optical image of an object,
A linear image sensor including a plurality of photoelectric conversion elements arranged in a straight line and outputting line image data of the object;
Conveying means for conveying the object in a sub-scanning direction orthogonal to the main scanning direction of the linear image sensor;
Storage means for storing a plurality of the line image data, each output from the linear image sensor at each position where the object is conveyed in the sub-scanning direction;
Based on the plurality of line image data stored in the storage means, the gradation values of the brightest pixels included in each of the plurality of line image data are matched with each other. And an image processing means for correcting each of the plurality of line image data. The image scanner device according to claim 1,
The image processing means includes
Main scanning direction correction means for performing shading correction on each of the plurality of line image data stored in the storage means based on white reference line master data stored in advance in the storage means;
White reference calculation means for calculating white reference gradation values from the plurality of line image data corrected by the main scanning direction correction means;
The main scanning direction correction unit corrects the tone value of the brightest line peak pixel included in each of the plurality of line image data to match the white reference tone value calculated by the white reference calculation unit. An image scanner apparatus comprising: a sub-scanning direction correcting unit that corrects each of the corrected plurality of line image data. The image scanner device according to claim 2,
The white reference calculation means includes
Line peak extraction means for extracting the brightest pixel included in each of the plurality of line image data corrected by the main scanning direction correction means as a line peak pixel;
An image scanner device comprising: white reference determination means for determining a gray reference value of a brightest pixel among the plurality of line peak pixels extracted by the peak extraction means as a white reference gradation value. In the image scanner device according to claim 2 or 3,
The sub-scanning direction correcting unit includes the white reference in which gradation values of the line peak pixels included in each of the plurality of line image data corrected by the main scanning direction correcting unit are calculated by the white reference calculating unit. An image scanner device that normalizes each of the plurality of line image data corrected by the main scanning direction correction unit so as to coincide with a gradation value. An image scanner device for reading an optical image of an object,
A linear image sensor including a plurality of photoelectric conversion elements arranged in a straight line and outputting line image data of the object;
Conveying means for conveying the object in a sub-scanning direction orthogonal to the main scanning direction of the linear image sensor;
Main scanning direction correction means for performing shading correction on the line image data output from the linear image sensor at each position where the object is conveyed in the sub-scanning direction, based on white reference line master data;
Storage means for storing the white reference line master data and a plurality of the line image data output from the main scanning direction correction means;
Based on the plurality of line image data stored in the storage means, the gradation values of the brightest pixels included in each of the plurality of line image data are matched with each other. And an image processing means for correcting each of the plurality of line image data.