JP2005208820A - Credit card reading device and credit card reading method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a credit card reading device and a credit card reading method for reducing the processing load of a device and the transfer load of a data transfer path, and for surely generating an image whose characters and background are discriminated on a credit card. <P>SOLUTION: A printer 10 with an image reading sensor is provided with an image reading sensor 44 for reading a credit card C to be conveyed on a card conveyance path in color and an image data generating part(binary image generating part 70 or gray scale image generating part 80) for generating image data based on a card image read by the image reading sensor 44. This image data generating part prepares a histogram based on a pre-scan image acquired from a credit card C by pre-scanning, and drives the image reading sensor 44 according to the histogram to operate main scanning. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a credit card reading device and a credit card reading method for reading an image of a credit card.

  An image scanner is generally used as an apparatus for acquiring image information drawn on a reading medium such as paper or a card. The image scanner irradiates the reading medium with light from an LED or the like provided in the reading head in a state where the reading head is in close contact with the reading medium, and the image reading sensor provided in the reading head reflects the light reflected on the reading medium. The image information on the reading medium is acquired by receiving the light using (see, for example, Patent Document 1).

  Various reading media can be read by the image scanner, but in some cases, a credit card image may be acquired. A credit card generally reads magnetic data held by a credit card by reading the magnetic data holding unit with a magnetic reader. For example, the magnetic reader fails or the magnetic data on the credit card is damaged. In such a case, it is considered effective to acquire image information on the surface of the credit card using an image scanner.

  FIG. 11A is a view of the credit card C as viewed from the front surface, FIG. 11B is a schematic diagram showing only the mark and design portion of the credit card C, and FIG. FIG. 4 is a diagram showing only the character information description portion of the credit card C taken out.

As shown in FIGS. 11A to 11C, various information is written on the surface of the credit card C.
For example, as shown in FIG. 11B, the credit card C has a design for improving the design of the card. In the case of this credit card C, a geometric pattern is designed by drawing two wavy lines L1 and L2 in the longitudinal direction of the card and drawing two straight lines L3 and L4 in the card width direction. Yes. And the mark M1, M2 which shows the kind of card company is given to the right side of the credit card C, and the whole image of the credit card C is decided. In the credit card C, in order to further improve the design, the regions R1 to R9 divided by the wavy lines L1 and L2 and the straight lines L3 and L4 are colored in various colors.

  Further, as shown in FIG. 11C, the credit card C identifies the card name C1 indicating the type of card issued by the card company, the card number C2 which is a card-specific number, and the card issuing company name. Card company code C3, credit card C expiration date C4, credit card C owner name C5, and the like. Of these, the card number C2, the card company code C3, the expiration date C4, the owner name C5, etc. are embossed. The embossing has a font that is raised from the back to the front.

When the image scanner reads an image on this type of card, the image is transferred to the host computer. Then, the host computer performs the OCR process to recognize characters of the image, display the obtained image on the screen, and print on a predetermined sheet. Here, in order to reduce the amount of data, the image scanner may transfer the image to the host computer after binarizing the read image.
JP-A-11-284801 (paragraph 0014, FIG. 1)

  When the above-described credit card C is read by a monochrome scanner, the character may be buried in the background depending on the balance between the background and the color tone of the character, and the character may not be correctly recognized from the read image. For example, if the characters to be read are colored with silver and the background is designed in the same silver color on the entire card, the characters in the image read in monochrome are almost assimilated with the background, In some cases, the character and background cannot be distinguished in the image. In particular, if such an image is binarized using a predetermined threshold, characters and background are mixed, and there is a high possibility that both cannot be distinguished in the image.

  Further, when a credit card is scanned by a scanner, the shadow of the emboss and the background of the credit card are assimilated, and the emboss may not be read correctly. Even in such a case, the character and the background may be mixed, and both may not be distinguished in the image.

  In order to solve this problem, it is conceivable to read a credit card using a color scanner. However, in the case of a color scanner, the load on the scanner and the data transfer load between the scanner and the host computer increase due to an increase in the amount of data, and a high-performance CPU or circuit for executing a credit card reading process is required. It will be requested.

  SUMMARY OF THE INVENTION In view of the above problems, the present invention is a credit card reading device capable of reliably generating an image in which characters on a credit card are distinguished from a background while reducing the processing load of the device and the transfer load of the data transfer path. And a credit card reading method.

The above object of the present invention is achieved by the following configurations.
(1) an image reading sensor capable of reading a credit card conveyed on the card conveying path with a plurality of colors of reading light;
An image data generation unit that processes image data read by the image reading sensor;
The image data generation unit creates a histogram based on a prescan image obtained from the credit card by prescan, and drives the image reading sensor according to the histogram to perform a main scan. Credit card reader.
(2) The image data generation unit selects reading light that can acquire image data having the clearest contrast between the character part and the background part in the credit card, according to the histogram,
The credit card reader according to (1), wherein the image reading sensor performs a main scan using the reading light.
(3) The image reading sensor performs the pre-scan using all of the reading lights of the plurality of colors,
The image data generation unit can create a histogram from image data corresponding to each reading light, and obtain image data with the clearest contrast between the character part and the background part in the credit card while referring to the histogram. (2) The credit card reading device according to (2), wherein the reading light is selected.
(4) The image data generation unit calculates a peak in the histogram created from the image data corresponding to each reading light, and performs the main scan using the reading light corresponding to the histogram having the maximum peak-to-peak distance. And
The credit card reader according to (3), wherein the image data obtained by the main scan is transmitted to a host computer.
(5) The image data generation unit binarizes the image data obtained in the main scan to generate binarized image data,
The credit card reader according to (4), wherein the binarized image data is transmitted to the host computer.
(6) When the peak-to-peak distance of the histogram in which the peak-to-peak distance calculated based on the histogram respectively created from the image data corresponding to each reading light is smaller than a predetermined value, the reading lights of the plurality of colors Perform a full scan using all of the
The credit card reader according to (4), wherein the image data obtained by the main scan is converted into grayscale image data and transmitted to the host computer.
(7) Further, a transport roller that transports the credit card from the card insertion slot in the forward direction along the card transport path and then transports the credit card in the reverse direction along the card transport path to the card insertion slot. With
The image reading sensor performs the pre-scan while the credit card is conveyed in the forward direction, and performs a main scan while the credit card is conveyed in the reverse direction. The credit card reader according to any one of the above.
(8) Any one of (1) to (7), wherein the image reading sensor is a color image reading sensor, and the plurality of reading lights are lights corresponding to R, G, and B, respectively. The credit card reader according to item.
(9) pre-scanning the credit card to obtain a pre-scan image;
Creating a histogram of the pre-scanned image;
A credit card reading method comprising: performing a main scan of the credit card according to the histogram.
(10) according to the histogram, further comprising the step of selecting any one of a plurality of colors of reading light capable of acquiring image data with the clearest contrast between the character portion and the background portion in the credit card;
The credit card reading method according to (9), wherein the main scan is performed using the selected reading light.
(11) The pre-scan is performed using all of the reading lights of the plurality of colors,
Create a histogram from the image data corresponding to each reading light,
(10) wherein any one of the plurality of reading lights capable of acquiring image data having the clearest contrast between a character portion and a background portion in the credit card is selected with reference to each histogram. Credit card reading method.
(12) calculating a peak in a histogram respectively created from image data corresponding to each reading light;
Performing a main scan using the reading light corresponding to a histogram having a maximum peak-to-peak distance;
And a method of transmitting image data obtained by the main scan to a host computer.
(13) The credit card reading method according to (12), further comprising the step of binarizing the image data obtained in the main scan to generate binarized image data.
(14) When the peak-to-peak distance of the histogram in which the peak-to-peak distance calculated based on the histogram respectively created from the image data corresponding to each reading light is smaller than a predetermined value, the plurality of reading lights Perform a full scan using all
(12) The credit card reading method according to (12), wherein the image data obtained by the main scan is converted into grayscale image data and transmitted to the host computer.
(15) The pre-scan is performed while the credit card is transported in the forward direction along the card transport path, and the main scan is performed while the credit card is transported in the reverse direction along the card transport path. The credit card reading method according to any one of (9) to (14), wherein:

  In the credit card reader and the reading method of the present invention, a reading light that can acquire an image that is most easily recognized by OCR is selected from a plurality of reading lights. Therefore, it is possible to transmit image data having the clearest contrast between the character portion and the background portion in the image of the credit card to the host computer. Therefore, it is possible to improve the accuracy of character recognition in the host computer.

  In the credit card reading apparatus and reading method of the present invention, only the image data acquired from at least one of the plurality of reading lights is transmitted to the host computer, so that the data amount of the image data transmitted to the host computer Is equivalent to the data amount of image data acquired by a monochrome image reading sensor having only a single light source. Therefore, in the credit card reading apparatus and reading method of the present invention, the internal processing load is reduced by minimizing the amount of image data to be handled, and the transfer load due to the transfer of the image data is acquired by the monochrome image reading sensor. It is possible to keep the same load as the transfer load of the image data.

  Hereinafter, embodiments of a credit card reading apparatus and a credit card reading method according to the present invention will be described in detail with reference to the drawings.

  The printer 10 with an image reading sensor of this embodiment is connected to a host computer 100 so as to be communicable as shown in FIG. 5 (FIG. 5 will be described in detail later). The printer 10 with an image reading sensor operates in accordance with various commands transmitted from the host computer 100, reads an image on the credit card C, and transmits it to the host computer 100. The host computer 100 is configured to perform OCR processing on the image of the credit card C transmitted from the printer 10 with an image reading sensor, and to recognize characters in the image of the credit card C.

  Here, in order for the host computer 100 to perform highly accurate character recognition, the printer 10 with an image reading sensor acquires image data with a clear contrast between the character portion of the credit card C and the background portion, and transmits it to the host computer 100. It is preferable to do. In consideration of the processing load of the printer 10 with the image reading sensor and the data transfer load to the host computer, it is preferable that the amount of image data processed by the printer 10 with the image reading sensor is as small as possible.

  Therefore, in the present embodiment, the credit card C can be read with a plurality of colors of reading light, that is, pre-scanning is performed using the color image reading sensor 44, and among the image data generated from each of the reading lights of a plurality of colors. The reading light corresponding to the image data with the clearest contrast is set as the reading light at the time of the main scanning, and the main scanning is performed using only the selected reading light, and the image data to be transmitted to the host computer 100 is generated. It is composed.

  In the following description, the structure of the printer 10 with an image reading sensor will be described first, and then image reading control of the credit card C will be described.

(Structure of printer with image reading sensor)
FIG. 1 is an external perspective view showing a printer 10 with an image reading sensor, which is a credit card reader according to the present embodiment. FIG. 2 is a partial cross-sectional view of the printer 10 with an image reading sensor. FIG. 3 is a perspective view showing an upper surface lid portion of the printer 10 with an image reading sensor. FIG. 4 is a cross-sectional view showing the upper surface side of the card transport path in a state where the inner cover is opened.

  The printer 10 with an image reading sensor of the present embodiment is a printer with a scanner that can print on both roll paper P and slip paper S and can read image information recorded on the slip paper S, credit card C, and the like. is there.

  The printer 10 with an image reading sensor accommodates a roll paper P as continuous paper in a housing 11a, and includes a back side housing unit 11 having a printing mechanism and the like for printing on the roll paper P, and a back side housing. A front-side housing unit 12 that is provided on the front side of the body unit 11 and defines a slip paper transport path 21 through which the slip paper S is transported between the back-side housing unit 11 and the back-side housing unit 11. A top cover body portion 13 for housing a card image reading sensor and the like for reading image information recorded on a medium such as a credit card C is integrally formed.

  Here, the front-side housing unit 12 includes a front-side cover 12a that is separated from the housing unit 11 via the slip paper conveyance path 21, and a front-side side portion 12b that holds the front cover 12a in a single-supported state. It is configured. As shown in FIG. 1, the slip paper S is on the front side of the printer 10 with an image reading sensor, and the housing 11 a of the rear housing unit 11 and the front housing unit 12 of the front housing unit 12. It can be inserted into the slip paper transport path 21 from a slip paper insertion port 21a opened between the front cover 12a and the front cover 12a.

  The slip paper transport path 21 is provided with a plurality of transport rollers (not shown), and the slip paper S is printed on the front or back surface while being transported by these transport rollers. Further, a slip paper image reading sensor (not shown) is provided in the slip paper conveyance path 21 so that an image on the surface of the slip paper S can be read. Further, a MICR reading sensor (not shown) is provided in the vicinity of the slip paper insertion opening 21a so that MICR characters printed on the slip paper S can be read.

  Next, the operation of the roll paper conveyance path 35 and each member disposed in the vicinity of the roll paper conveyance path 35 will be described with reference to FIG. A roll paper transport path 35 is formed between the housing unit 11 and the upper surface side lid unit 13. The roll paper P is loaded in a roll paper storage unit 30 formed by a roll paper storage wall 31 provided inside the back side housing unit 11. The roll paper P is sent out along the roll paper conveyance path 35 and discharged from a roll paper discharge port 35a opened between the housing 11a and the upper surface cover 13a.

  The roll paper storage unit 30 is a drop-in roll paper storage unit, and the roll paper P is loaded and loaded into the roll paper storage unit 30. The roll paper P is supplied by the roll paper P rotating while being guided by the roll paper storage wall 31. One end of the roll paper P disposed in the roll paper storage unit 30 is pulled out from the roll paper storage unit 30 and is printed by the thermal print head 33 while being conveyed by the platen roller 32. The printed roll paper P passes through the roll paper transport path 35 and is discharged from the roll paper discharge port 35a.

  As shown in FIG. 2, an auto cutter 34 is disposed above the platen roller 32 and the thermal print head 33. The auto cutter 34 has a fixed blade 34a disposed on one side of the roll paper transport path 35 and a movable blade 34b disposed on the other side of the roll paper transport path 35 corresponding to the fixed blade 34a. The movable blade 34b moves in the direction of arrow A in FIG. 2 toward the roll paper transport path 35, and the roll paper P is cut by sandwiching the roll paper P with the fixed blade 34a.

  A frame 51 is provided as a main skeleton at the lower portion of the upper surface lid body portion 13. The frame 51 is configured to be rotatable with respect to a fixed portion 53 provided on the back side housing portion 11 via a hinge portion 52, whereby the upper surface lid portion 13 is configured to be a roll paper storage portion. 30 can be opened and closed. When the roll paper P is exchanged, the top cover body portion 13 is opened via the hinge portion 52 and the roll paper P can be inserted into the roll paper storage portion 30.

  Next, the card image information reading unit 40 will be described. The card image information reading unit 40 is a sheet feed type image scanner, and reads an image on the credit card C while conveying the credit card C as a reading medium. As shown in FIG. 2, the card image information reading unit 40 is provided between the top cover 13a and the roll paper storage unit 30, and the credit card C or the like is inserted into the card insertion slot 41a shown in FIGS. The image information on the credit card C can be read by being inserted into the card conveyance path 41. As shown in FIG. 3, a table 13b that guides the credit card C and assists the insertion of the credit card C is formed on the front side of the card insertion slot 41a of the top cover 13a. An LED display unit 16 is provided on the top cover 13a adjacent to the card insertion slot 41a to notify the user of the status of the printer related to the credit card C reading operation.

  In the card image information reading unit 40, a first feed roller 43 a, a card image reading sensor 44, and a second feed roller 46 a are provided along the card transport path 41 on the upper surface side of the card transport path 41, that is, on the upper cover 13 a side. Has been placed. On the other hand, on the lower surface side of the card transport path 41, that is, on the roll paper storage unit 30 side, a first pressing roller 43b, a pressing roller 45, and a second pressing roller 46b are respectively a first feeding roller 43a and a card image reading sensor 44. , And the second feed roller 46a.

  The first feed roller 43 a and the first pressing roller 43 b are disposed between the card insertion opening 41 a and the card image reading sensor 44 (upstream side of the card image reading sensor 44), and are inserted into the card transport path 41. The credit card C can be transported back and forth along the card transport path 41. The credit card C conveyed by the first feeding roller 43a and the first pressing roller 43b is sent between the card image reading sensor 44 and the pressing roller 45.

  The card image reading sensor 44 is a CIS type color image sensor that reads characters and images recorded on the surface of the credit card C. The card image reading sensor 44 reads image information such as characters and images while being appropriately pressed by the pressing roller 45 against the reading surface 44a of the card image reading sensor 44 with a pressing force corresponding to the card thickness. Specifically, the card image reading sensor 44 sequentially irradiates R, G, and B light from the R light source 44b, the G light source 44c, and the B light source 44d on the upper surface of the credit card C that is transported through the card transport path 41. Each light reflected on the credit card C is received by the reading surface 44a. On the reading surface 44a side, a plurality of photoelectric conversion elements (not shown) are arranged in a line in the longitudinal direction (the direction perpendicular to the card carrying direction, the width direction of the credit card C), and each photoelectric conversion element receives light. An electric signal corresponding to the amount of light is generated. Here, each photoelectric conversion element is configured to read an image with 8-bit gradation (256 gradations).

  The second feed roller 46 a and the second pressing roller 46 b are arranged on the downstream side of the card image reading sensor 44, and convey the credit card C inserted into the card conveyance path 41 back and forth along the card conveyance path 41. It is configured to be possible.

  Further, an overhanging opening 41b is opened at a position downstream of the second feeding roller 46a and the second pressing roller 46b and intersecting the card transport path 41 and the upper surface cover 13a. This overhanging opening 41b is sent out to the downstream side of the card conveying path 41 in a state where the credit card C in the card conveying path 41 is nipped by the second feeding roller 46a and the second pressing roller 46b to temporarily store the image. It is allowed to project from the back side of the printer 10 with the reading sensor.

  The first pressing roller 43b, the pressing roller 45, and the second pressing roller 46b arranged on the roll paper storage unit 30 side rotate to the inner cover 42 arranged between the card transport path 41 and the roll paper storage unit 30. Supported as possible. The inner cover 42 has a card transport surface 42a that forms a card transport path 41 formed on the upper surface thereof, and the first pressing roller 43b, the pressing roller 45, and the second pressing roller 46b are partially protruded from the card transport surface 42a. The first feed roller 43a, the card image reading sensor 44, and the second feed roller 46a can be brought into contact with each other.

  The inner cover 42 is rotatably attached to guide walls 54, 54 erected substantially perpendicularly to the card conveying direction from the upper surface lid body 13 side via a hinge portion 55. More specifically, the hinge portion 55 is provided on the rear side of the inner cover 42, and the front side of the inner cover 42 facing upward is the front side of the printer 10 with the upper surface lid portion 13 being opened. The various members of the card transport path 41 can be maintained from the front side of the printer 10.

  Moreover, the guide walls 54 and 54 to which the inner cover 42 is attached serve as guide members for correcting the insertion direction of the credit card C inserted into the card transport path 41 as shown in FIG. For example, when the credit card C is inserted slightly obliquely with respect to the card transport direction (here, the direction perpendicular to the card insertion slot 41a and parallel to the paper transport surface 42a), the first feed roller 43a and While being conveyed by the second feed roller 46a, it is guided in contact with one of the wall surfaces of the guide walls 54, 54, whereby the insertion direction of the credit card C is bent and the conveyance direction of the credit card C is the card conveyance. Align in the direction. Thereby, even if the insertion direction of the credit card C has a little angle with respect to the card conveyance direction, the credit walls C are conveyed along the card conveyance direction. .

  This correction of the card conveying direction is conveyed in the forward direction from the card insertion opening 41a toward the overhanging opening 41b by the first feeding roller 43a and the first pressing roller 43b and the second feeding roller 46a and the second pressing roller 46b. This is performed until the credit card C completely passes the card image reading sensor 44. Then, after the credit card C has completely passed through the card image reading sensor 44, the credit card C is conveyed to the reading surface 44a of the card image reading sensor 44 in the reverse direction. As a result, the card image reading sensor 44 can accurately read the image information of the credit card C with the orientation of the credit card C always aligned.

  In the present embodiment, the card image reading sensor 44 performs a pre-scan of the image of the credit card C while the credit card C is conveyed in the forward direction from the card insertion opening 41a side toward the protruding opening 41b. Then, the main scan of the image of the credit card C is performed while the credit card C is conveyed from the overhanging opening 41b toward the card insertion slot 41a. Details of the image reading will be described later.

  Further, as shown in FIG. 4, a card detector 48 is provided in the vicinity of the card insertion slot 41 a of the card transport path 41. The card detector 48 is a sensor that detects the credit card C inserted from the card insertion slot 41a. The first feed roller 43a and the second feed roller 46a are configured to start driving after being detected by the card detector 48, and the insertion of the credit card C is used as a trigger in the card transport path 41. The card feeding operation is started.

(Control circuit for printer with image reading sensor)
Next, the image reading of the credit card C in the printer 10 with the image reading sensor of the present embodiment will be described in detail.
FIG. 5 is a block diagram showing components related to image reading control of the credit card C of the printer 10 with an image reading sensor of the present embodiment. Here, only main components related to reading of the credit card C will be described, and description of circuit members related to printing and reading of the slip paper S and printing of the roll paper P will be omitted.

  In the printer 10 with an image reading sensor of this embodiment, as shown in FIG. 5, the firmware written in the ROM 62 is read into the RAM 61 and executed by the CPU 60, and the stepping motor 63, the card detector 48, and the gate array are executed. 64, the A / D converter 65, the card image reading sensor 44, and the communication interface 66 are controlled in an integrated manner.

  The stepping motor 63 is a motor whose rotation speed can be controlled in steps in accordance with the number of control pulse signals from the CPU 60. The output of the stepping motor 63 is transmitted to the first feed roller 43a and the second feed roller 46a, and drives the first feed roller 43a and the second feed roller 46a. Thereby, the rotation amount of the first feed roller 43a and the second feed roller 46a, that is, the transport length of the credit card C is controlled in accordance with the number of steps of the stepping motor 63.

  The card detector 48 detects the presence or absence of the credit card C inserted from the card insertion slot 41a, and determines whether or not the credit card C exists in the detection area of the credit card C. The CPU 60 controls the transfer of the credit card C according to the detection result of the card detector 48.

  The A / D converter 65 converts the electrical signals for one line of RGB output from the photoelectric conversion elements of the card image reading sensor 44 into digital signals. The A / D converter 65 may be configured to perform A / D conversion after adjusting the offset and gain of the electrical signal output from each photoelectric conversion element in the previous stage of conversion to a digital signal.

  The gate array 64 is a line buffer for temporarily storing a digital signal for one line created by the A / D converter 65. The digital signal for one line stored in the gate array 64 is transferred to the RAM 61 and stored in the card image storage area 61 a in the RAM 61. In the card image storage area 61a of the RAM 61, image data acquired from the credit card C is stored line by line, and a two-dimensional image of the credit card C is finally obtained. In this card image storage area 61a, image data read by prescan (hereinafter referred to as prescan image data) is also stored.

  The communication interface 66 controls communication with the host computer 100 installed outside the printer 10 with an image reading sensor. The communication interface 66 receives various control commands from the host computer 100 and transmits them to the CPU 60. The CPU 60 executes reading of the credit card C, transmission of the acquired image data to the host computer 100, change of internal settings of the printer 10 with an image reading sensor, and the like in accordance with these various control commands.

(Pre-scan and main scan)
In the present embodiment, as described above, the image reading sensor 44 performs a pre-scan of the image of the credit card C while the credit card C is conveyed in the forward direction from the card insertion opening 41a side toward the protruding opening 41b. Then, while the credit card C is conveyed from the overhanging opening 41b toward the card insertion slot 41a, the image scanning sensor 44 performs a main scan of the image of the credit card C.

  In the pre-scan, all of the important parts in image recognition, specifically, the card number C2, the card company code C3, the expiration date C4, and the owner name C5, which are character information description parts shown in FIG. Alternatively, color image reading is performed using all of the RGB light emitted from the R light source 44b, the G light source 44c, and the B light source 44d so that at least a part of the image (image of the embossed portion) is acquired.

  On the other hand, in the main scan, image reading is performed so that an image of the entire credit card C shown in FIG. At the time of this main scan, image reading is performed using one of RGB reading light or all of RGB reading light in the color image reading or card image reading sensor 44 according to conditions described later. Here, “reading an image using any one of RGB reading light” means that only one of the RGB light sources 44b to 44d is driven to generate a single color image. It is also possible to drive all of the RGB light sources 44b-44d to collect data corresponding to all of the RGB read light, and discard or ignore data from the two unnecessary light sources to produce a single color image. It may be generated. A specific description of this image reading will be described later.

  In this embodiment, when the main scan image data is generated, the image data is formed only from a single reading light, so that the finally generated image data is 256 grayscale image data. . The gray scale image data may be transferred to the host computer 100 as it is, or may be transferred to the host computer 100 after being converted into binary image data in order to reduce the data transfer load. You may comprise. Hereinafter, a case where image data to be transmitted to the host computer 100 is binarized image data and a case of gray scale will be described.

(Generation of binarized image data)
First, binarized image data generation will be described.
FIG. 6 is a block diagram showing data processing for generating binarized image data inside the printer 10 with an image reading sensor.
In the present embodiment, the CPU 60 executes the binarized image generation program described in the firmware, whereby the following operations of the respective units in the binarized image generation unit 70 are executed.

  The binarized image generating unit 70 is a processing unit for binarizing the image data stored in the image storage area 61a of the RAM 61 based on a predetermined algorithm. Specifically, the binarized image generating unit 70, A histogram analysis unit 72, a histogram comparison determination unit 73, a gray scale creation unit 74, a binarization processing unit 75, and an image adjustment unit 76 are included.

  The binarized image generation unit 70 of the present embodiment selects an image color that maximizes the contrast between the character portion and the background portion by analyzing pre-scan image data that includes three types of RGB images. Then, a main scan is performed with the selected image color, and image data obtained by the main scan is binarized. In addition, when the image color that maximizes the contrast between the character part and the background part cannot be selected, for example, when the contrast is not clear for all colors, the main scan is performed using the three colors of RGB, The binarization process is performed by converting the image data obtained in the main scan into a gray scale. Hereinafter, specific functional units of the binarized image generation unit 70 will be described.

  The histogram creation unit 71 reads the prescan image data stored in the image storage area 61a, decomposes the read prescan image data for each color of RGB, and creates three types of histograms corresponding to each color. .

FIG. 7 is a diagram schematically showing processing by the histogram creation unit 71, and FIG. 7A is a diagram schematically showing RGB decomposition and gray scale conversion of image data, and FIG. ) Is a graph showing a histogram created for each RGB.
As shown in FIG. 7A, the histogram creating unit 71 decomposes the pre-scan image (color image) D1 for each RGB component to obtain an R image D2, a G image D3, and a B image D4. A histogram as shown in FIG. 7B is created for each time.

  In FIG. 7A, the pre-scan image D1 is, for example, an image in which the background portion D1a is mugwort and the character portion D1b is yellow. In the R image D2 obtained by decomposing such prescan image data D1 for each RGB, the background portion D2a is dark red and the character portion D2b is light red. Further, in the G image D3, the background portion D3a is green, and the character portion D3b is green with substantially the same darkness as the background portion. In the B image D4, the background portion D4a is dark blue and the character portion D4b is almost blue.

  In FIG. 7A, lines between the background portions D1a, D2a, D3a, and D4a and the character portions D1b, D2b, D3b, and D4b indicate the ease of distinguishing between the background portion and the character portion depending on the type. The thick line D2 is the easiest to distinguish (that is, the contrast is clear), and it is difficult to distinguish D4, D1, D3, and D5 in this order. The histogram shown in FIG. 7B is obtained by quantifying the ease of distinguishing the background portion and the character portion on the basis of the luminance, and indicates that the larger the interval between two peaks, the easier it is to distinguish.

  Here, the reason why each histogram has two peaks is that the pre-scan image is composed of only characters and two kinds of background colors. In general, more peaks can be seen and a smooth continuous spectrum can be seen. It may become. For example, in the case of the credit card C as shown in FIG. 11A, since a plurality of colors are included, it is expected that more peaks are observed. In such a case, prescan is performed in a narrow region including only character information as much as possible, prescan is performed so that various background colors are not mixed in the prescan image, and a luminance peak corresponding to the character portion is detected. It is preferable that the luminance peak corresponding to the background portion appears clearly.

  The histogram analysis unit 72 analyzes the respective RGB histograms created by the histogram creation unit 71, finds the luminance position of the largest peak and the second largest peak, and calculates the luminance difference between these peaks. Taking FIG. 7B as an example, the interval between two peaks of “R histogram”, “G histogram” and “B histogram” is obtained.

  The histogram comparison / determination unit 73 compares the intervals of the two peaks “R histogram”, “G histogram” and “B histogram” obtained by the histogram analysis unit 72, and determines the histogram having the widest interval. Ask. If the interval of the histogram having the widest interval is equal to or greater than a predetermined value, the image color corresponding to the histogram having the widest interval is set as the image color to be binarized (for example, the image is stored in the RAM 61). Set the flag corresponding to the color). Then, a representative value between two peaks is selected and determined as a threshold value for binarization. This representative value may be, for example, the central value between two peaks, or may be obtained by adding a predetermined value to this central value or multiplying a predetermined ratio. .

  The fact that the interval between the two peaks in the histogram is the widest means that the image data has the most emphasized contrast between the background portion and the character portion. That is, obtaining the histogram with the widest peak interval from the “R histogram”, “G histogram” and “B histogram” and selecting the reading light corresponding to the image color of the histogram with the widest peak interval is: In other words, the reading light with which the contrast between the character part and the background part is the largest when the image is acquired, in other words, the image that can easily perform the character recognition when the OCR process is performed is selected.

  On the other hand, if the interval of the histogram having the widest interval is smaller than a predetermined value, the image color to be binarized is set to gray scale. (For example, a flag corresponding to the gray scale is set in the RAM 61). Here, that the interval of the histogram having the widest interval is smaller than a predetermined value means that the contrast is not so clear. In other words, if the contrast is not clear with any reading light, the main scan image data is not generated only with a single reading light, but all of the RGB of the card image reading sensor 44 is read. Color main scan image data is generated by pixels, and the obtained main scan image data is converted to gray scale.

  In the case of FIG. 7B, since the two peak intervals of the “R histogram” are the largest, the image color corresponding to the “R histogram” if the interval between the two peaks is equal to or greater than a predetermined value. R is set as an image color for performing the main scan and binarization processing, and a threshold value is determined. On the other hand, if the peak interval in the “R histogram” is smaller than a predetermined value, the image color for the main scan is set to all RGB colors, and the image color for the binarization process is set to gray scale.

  In the present embodiment, the processing of the histogram comparison determination unit 73 is performed before the main scan is performed. During the main scan, the card image reading sensor 44 reads an image with a color corresponding to the flag set in the RAM 61. Specifically, if R is set as the image color for generating the binarized image, the main scan image data is generated using only data obtained from the R light source 44b of the card image reading sensor 44. If G or B is set as an image color for generating a binarized image, the main scan image data is generated using only data obtained from the G light source 44c or B light source d of the card image reading sensor 44. To do. On the other hand, if all RGB images are set as image colors for binarization processing, image reading is executed using all RGB reading light. The read main scan image data is stored in the image storage area 61 a in the RAM 61.

The gray scale creation unit 74 creates gray scale image data based on the main scan image data which is a color image acquired when the gray scale is set as the image color to be binarized. The color image data has 256 gradation data for each RGB color for each pixel (pixel), and can express 16,777,216 full colors (24 bits) as a whole. The gray scale creation unit 74 creates a gray scale data of 256 gradations for each pixel by applying a predetermined weight to each color of the pre-scan image data. Specifically, the gray scale creation unit 74 performs conversion for each pixel based on the following formula (1) to generate gray scale image data.

Yc ₂₅₆ = INT [0.299R / 256 + 0.587G / 256 + 0.114B / 256] × 256 (1)

Here, Yc ₂₅₆ is a luminance value of 256 gray scale gray scale data, and R, G, and B indicate R, G, and B luminance values in a certain pixel, respectively.

  The binarization processing unit 75 binarizes the main scan image data stored in the image storage area 61a in accordance with the determination result of the histogram comparison determination unit 73. As described above, when the main scan is generated using only one of the R, G, and B light sources 44b to 44d of the card image reading sensor 44, the main scan is acquired at the time of the main scan. The corresponding image data 61a is 256-tone single color image data. The main scan image data includes data read by an 8-bit gradation monochrome image reading sensor except that it is generated by reading light emitted from any one of the light sources 44b to 44d of R, G, and B. It is the same.

  The binarization processing unit 75 binarizes the main scan image data based on the threshold value determined by the histogram comparison determination unit 73 to generate binarized image data. When the grayscale image data is created by the grayscale creation unit 74, the grayscale image data is used as the main scan image data, and binarized based on a predetermined threshold value. Generate data. The threshold for conversion from grayscale image data to binarized image data may be determined in advance, or may be determined based on the luminance distribution in the grayscale image data.

The image adjustment unit 76 adjusts the binarized image data generated by the binarization processing unit 75 such as sharpness, noise removal, and data compression, and outputs the result. The output binarized image data is stored in the image storage area 61 a of the RAM 61, or is output as it is to the host computer 100 via the communication interface 66.
The above is the description of the processing by the binarized image generation unit 70.

(Image generation processing procedure)
Next, the flow of the binarized image reading process will be described in order with reference to FIG.
FIG. 8 is a flowchart showing the flow of the binarized image reading process in the printer 10 with the image reading sensor of the present embodiment.
The printer 10 with an image reading sensor of this embodiment basically reads an image of the credit card C in response to a scan command instructed to read the image of the credit card C transmitted from the host computer 100.

  Specifically, as shown in FIG. 8, when the printer 10 with an image reading sensor receives a scan command from the host computer 100 (step S1), the internal state of the printer 10 with an image reading sensor is in a paper insertion waiting state. Transition. The printer 10 with the image reading sensor waits until the credit card C is inserted, that is, until the credit card C is inserted into the card transport path 41 from the card insertion port 41a and the card detector 48 detects the credit card C. (Step S2).

  When the credit card C is detected in step S2, the stepping motor 63 is driven in the forward direction to rotate the first feed roller 43a and the first pressing roller 43b, and the credit card C is directed toward the overhanging opening 41b. Is conveyed in the card conveyance direction (forward direction). Here, the CPU 60 detects the card length of the credit card C based on the rotation of the stepping motor 63 while the credit card C is conveyed in the forward direction from the card insertion slot 41a toward the overhanging opening 41b. The reading sensor 44 pre-scans the image on the credit card C using the reading light from the three types of RGB light sources 44b to 44d. The read image is temporarily stored as pre-scan image data in the image storage area of the RAM 61 (step S3).

  When the pre-scan image is stored in the image storage area 61a, the CPU 60 and the RAM 61 function as the two-dimensional image generation unit 70 by performing an operation based on the firmware.

  The two-dimensional image generation unit 70 first decomposes the pre-scan image data for each color of RGB in the histogram creation unit 71, and three types of histograms corresponding to each color (“R histogram”, “G histogram”). And “Histogram of B”). Then, the histogram analysis unit 72 analyzes each of the RGB histograms created by the histogram creation unit 71, finds the luminance position of the largest peak and the second largest peak, and calculates the luminance difference between these peaks. (Step S4).

  Next, the histogram comparison / determination unit 73 compares the two peak intervals of the “R histogram”, “G histogram”, and “B histogram” obtained by the histogram analysis unit 72 with each other, and the peak interval is the maximum. The color having the maximum peak interval is determined (step S5).

  In step S6, it is confirmed whether the peak interval of the histogram having the maximum peak interval is equal to or greater than a predetermined value.

  Here, if the peak interval of the histogram having the maximum peak interval is equal to or greater than a predetermined value, the image color corresponding to the histogram having the maximum peak interval is set as the image color for performing the main scan and binarization processing. To do. Then, a representative value between two peaks is selected and determined as a threshold value for binarization. Then, the stepping motor 63 is driven in the reverse direction, and the main scan (in this case, the monochromatic scan) is executed while the credit card C is conveyed from the overhanging opening 41b toward the card insertion port 41a. In this main scan, the credit card C is conveyed step by step, and the main scan image data is generated using one of the light sources 44b to 44d corresponding to the image color for executing the main scan in the card image reading sensor 44. . . The generated main scan image data (monochromatic image data) is stored in the image storage area 61a of the RAM 61a (step S7).

  On the other hand, if the peak interval of the histogram having the maximum peak interval is smaller than a predetermined value, it is set that all RGB colors are used as the image color during the main scan and binarization processing is performed using grayscale image data. Then, the stepping motor 63 is driven in the reverse direction so that the credit card C is conveyed from the overhanging opening 41b toward the card insertion port 41a, and all the RGB light sources 44b to 44d in the card image reading sensor 44 are used. Scan (here, color scan) is executed. The read main scan image data (color image data) is stored in the image storage area 61a of the RAM 61a. The main scan image data is converted into grayscale image data by the grayscale creation unit 74 (step S8).

When the main scan is completed in step S7 or step S8, the credit card C is discharged to the card insertion slot 41a side. Then, binarized image data is generated based on the main scan image data or the grayscale image data acquired by the binarization processing unit 75, and predetermined image processing is performed by the image adjustment unit 76 (step S9). .
Thereafter, the binarized image data is temporarily stored in the image storage area 61a of the RAM 61 or transmitted to the host computer 100 (step S10).
Thus, the image reading process for the credit card C is completed.
Thereafter, the host computer 100 performs OCR processing on the received binarized image data and recognizes character information in the image of the credit card C. As a result, it is possible to acquire image information and character information of the credit card C.

(Generation of grayscale image data)
Next, generation of grayscale image data will be described.
FIG. 9 is a block diagram showing data processing for generating data inside the printer 10 with an image reading sensor.
Also in this case, when the CPU 60 executes the gray scale image generation program described in the firmware, the operation of each unit in the gray scale image generation unit 80 shown below is executed.

  The gray scale image generation unit 80 is a processing unit for generating a gray scale using the card image reading sensor 44 that is a color scanner. Specifically, the histogram generation unit 81, the histogram analysis unit 82, and the histogram comparison The determination unit 83, the gray scale creation unit 84, and the image adjustment unit 85 are configured.

  The gray scale image generation unit 80 according to the present embodiment selects the image color that maximizes the contrast between the character portion and the background portion by analyzing pre-scan image data having three types of RGB images. The main scan is performed with the selected image color, and the image data obtained by the main scan is directly used as grayscale image data. In addition, when the image color that maximizes the contrast between the character part and the background part cannot be selected, for example, when the contrast is not clear for all colors, the main scan is performed using the three colors of RGB, The image data obtained by converting the image data obtained in the main scan into gray scale is used as gray scale image data. Hereinafter, specific functional units of the gray scale image generation unit 80 will be described.

  The histogram creation unit 81 reads the prescan image data stored in the image storage area 61a, decomposes the read prescan image data for each color of RGB, and creates three types of histograms corresponding to each color. The basic function is the same as that of the histogram creation unit 71 described above.

  The histogram analysis unit 82 analyzes each of the RGB histograms created by the histogram creation unit 81, finds the luminance position of the largest peak and the second largest peak, and calculates the luminance difference between these peaks. The histogram analysis unit 82 has the same basic functions as the histogram analysis unit 72 described above.

  The histogram comparison / determination unit 83 compares the intervals of the two peaks “R histogram”, “G histogram”, and “B histogram” obtained by the histogram analysis unit 82, and determines the histogram having the widest interval. Ask. If the interval of the histogram having the widest interval is equal to or greater than a predetermined value, the image color corresponding to the histogram having the widest interval is set as the image color for performing the main scan (for example, the image color is set in the RAM 61). Set the corresponding flag). In this case, during the main scan, single-color main scan image data is generated from data obtained from the light sources 44b to 44d of the card image reading sensor 44 corresponding to the image color corresponding to the histogram having the widest interval. The The obtained main scan image data is equivalent to the gray scale image obtained from the monochrome scanner.

  On the other hand, if the interval of the histogram having the widest interval is smaller than a predetermined value, the histogram comparison / determination unit 83 sets the image colors for the main scan to three colors of RGB. (For example, flags corresponding to three colors of RGB are set in the RAM 61). In this case, during the main scan, all the RGB light sources 44b to 44d of the card image reading sensor 44 are driven, and color main scan image data is acquired.

  The gray scale creation unit 84 functions when the image color for performing the main scan is set to three colors of RGB, and creates gray scale image data based on the acquired color main scan image data. . The gray scale creation unit 84 is similar in basic function to the gray scale creation unit 82 described above, and converts RGB color image data into gray scale image data based on the above-described equation (1). To do.

The image adjustment unit 85 performs adjustments such as sharpness, noise removal, and data compression on the main scan image data acquired by the main scan or the gray scale image data generated by the gray scale generation unit 84 and outputs the result. The output binarized image data is stored in the image storage area 61 a of the RAM 61, or is output as it is to the host computer 100 via the communication interface 66.
The above is description of the process by the gray scale image generation part 80. FIG.

(Image generation processing procedure)
Next, the flow of the gray scale image reading process will be described in order with reference to FIG.
FIG. 10 is a flowchart showing a flow of gray scale image reading processing in the printer 10 with an image reading sensor of the present embodiment.

  As shown in FIG. 10, when the printer 10 with an image reading sensor receives a scan command from the host computer 100 (step S11), the internal state of the printer 10 with the image reading sensor transitions to a paper insertion waiting state. The printer 10 with an image reading sensor until the credit card C is inserted, that is, until the credit card C is inserted into the card transport path 41 from the card insertion slot 41a and the card detector 48 detects the credit card C. Wait (step S12).

  When the credit card C is detected in step S12, the stepping motor 63 is driven in the forward direction to rotate the first feed roller 43a and the first pressing roller 43b, and the credit card C is directed toward the overhanging opening 41b. Is conveyed in the card conveyance direction (forward direction). Here, the CPU 60 detects the card length of the credit card C based on the rotation of the stepping motor 63 while the credit card C is conveyed in the forward direction from the card insertion slot 41a toward the overhanging opening 41b. The reading sensor 44 pre-scans the image of the credit card C using three types of RGB light sources 44b to 44d. The read image is temporarily stored as pre-scan image data in the image storage area of the RAM 61 (step S13).

  When the prescan image is stored in the image storage area 61a, the CPU 60 and the RAM 61 function as the grayscale image generation unit 80 by performing an operation based on the firmware.

  The gray scale image generation unit 80 first decomposes the pre-scan image data for each color of RGB in the histogram creation unit 81, and three types of histograms corresponding to each color (“R histogram”, “G histogram”). And “Histogram of B”). Then, the histogram analysis unit 82 analyzes each of the RGB histograms created by the histogram creation unit 81, finds the luminance position of the largest peak and the second largest peak, and calculates the luminance difference between these peaks. (Step S14).

  Next, the histogram comparison / determination unit 83 compares the intervals of the two peaks “R histogram”, “G histogram”, and “B histogram” obtained by the histogram analysis unit 82, and the peak interval is the maximum. The color having the maximum peak interval is determined (step S15).

  In step S16, it is confirmed whether or not the peak interval of the histogram having the maximum peak interval is greater than or equal to a predetermined value.

  Here, if the peak interval of the histogram having the maximum peak interval is equal to or greater than a predetermined value, the image color corresponding to the histogram having the maximum peak interval is set as the image color for performing the main scan. Then, the stepping motor 63 is driven in the reverse direction, and the main scan (in this case, the monochromatic scan) is executed while the credit card C is conveyed from the overhanging opening 41b toward the card insertion port 41a. In this main scan, the credit card C main scan image data is transferred using only one of the light sources 44b to 44d of the card image reading sensor 44 corresponding to the image color for executing the main scan while carrying the credit card C step by step. Is generated. The generated main scan image data (monochromatic image data) is stored as grayscale image data in the image storage area 61a of the RAM 61a (step S17).

  On the other hand, if the peak interval of the histogram having the maximum peak interval is smaller than a predetermined value, all the RGB colors are set as the image colors during the main scan. Then, the stepping motor 63 is driven in the reverse direction so that the credit card C is conveyed from the overhanging opening 41b toward the card insertion port 41a while using data from all of the RGB light sources 44b to 44d in the card image reading sensor 44. Main scan image data (here, color scan image data) is generated. The read main scan image data is stored in the image storage area 61a of the RAM 61a. The main scan image data is converted into grayscale image data by the grayscale creation unit 74 (step S18).

When the main scan is completed in step S17 or step S18, the credit card C is discharged to the card insertion slot 41a side. The acquired main scan image data (grayscale image data) or grayscale image data is subjected to predetermined image processing by the image adjustment unit 85 (step S19).
Thereafter, the grayscale image data is stored in the image storage area 61a of the RAM 61 or transmitted to the host computer 100 (step S20).
Thus, the image reading process for the credit card C is completed.
Thereafter, the host computer 100 performs OCR processing on the received binarized image data and recognizes character information in the image of the credit card C. As a result, it is possible to acquire image information and character information of the credit card C.

  As described above, the printer 10 with an image reading sensor, which is a credit card reading device according to the present embodiment, includes a plurality of light sources 44b to 44d corresponding to RGB, and a plurality of credit cards C that are transported through the card transport path 41. And an image data generation unit (binarized image generation unit 70 or grayscale image generation unit 80) that processes image data read by the image reading sensor 44. The image data generation unit creates a histogram based on the prescan image obtained from the credit card C by the prescan, and drives the image reading sensor 44 according to the histogram to perform the main scan.

  Specifically, the image data generation unit selects any one of the RGB reading lights according to the created histogram, and the image reading sensor 44 generates the main scan image data by the selected reading light. To do. In this selection, the image data generation unit selects reading light that can acquire image data in which the contrast between the character portion and the background portion is most emphasized.

  Therefore, the printer 10 with an image reading sensor according to the present embodiment is configured to always select a light source that can acquire an image with the easiest OCR recognition from among the plurality of light sources 44b to 44d. The image data with the clearest contrast between the background portion and the background portion can be transmitted to the host computer 100. Therefore, it is possible to improve the accuracy of character recognition in the host computer 100.

  Further, since the printer 10 with an image reading sensor transmits only the image data acquired from at least one of the light sources 44b to 44d to the host computer 100, the data amount of the image data transmitted to the host computer 100 is as follows. The amount of image data acquired by a monochrome image reading sensor having only a single light source is about the same. Accordingly, the printer 10 with an image reading sensor reduces the internal processing load by minimizing the amount of image data to be handled, and the transfer load due to the transfer of the image data is acquired by the monochrome image reading sensor. It is possible to keep it at the same level as the transfer load. As a result, it is not necessary to separately prepare a transfer cable to the host computer that is faster than the conventional one, and the conventional one can be used as it is.

  Further, in the printer 10 with an image reading sensor, the image reading sensor 44 performs pre-scanning using all of the plurality of light sources 44b to 44d, and the image data generation unit respectively obtains image data corresponding to the light sources 44b to 44d. A histogram is created, and reading light capable of acquiring image data with the clearest contrast between the character portion and the background portion in the credit card C is selected while referring to each histogram.

  That is, in the present embodiment, a histogram is created from each image data acquired from each of the light sources 44b to 44d. Therefore, by referring to these histograms, it is possible to easily determine which image data obtained from the reading light output from each of the light sources 44b to 44d has the clearest contrast between the character portion and the background portion. it can.

  Specifically, the image data generation unit calculates a peak in the histogram created from the image data corresponding to each reading light, and performs the main scan using the reading light corresponding to the histogram having the maximum peak-to-peak distance. Thus, it is objectively determined which image data obtained from which reading light has the clearest contrast between the character portion and the background portion.

  In the present embodiment, the image data generation unit is configured to binarize the image data obtained in the main scan to generate binarized image data, and transmit the binarized image data to the host computer 100. May be. With this configuration, the amount of image data transmitted to the host computer 100 can be reduced, and the transfer load of image data to the host computer 100 can be further reduced.

  Further, in the present embodiment, when the peak-to-peak distance of the histogram at which the peak-to-peak distance calculated based on the histogram respectively created from the image data corresponding to each reading light is smaller than a predetermined value, a plurality of The main scan may be performed using all of the reading light, and the image data obtained by the main scan may be converted into grayscale image data and transmitted to the host computer. As a result, even when the main scan image data is generated using all of the RGB read lights, the transfer load of the image data can be reduced.

  In addition, without setting a predetermined value for the peak-to-peak distance of the histogram with the maximum peak-to-peak distance, the reading light corresponding to the histogram with the maximum peak-to-peak distance is unconditionally selected as the reading light for the main scan, and Regardless of the distance between the peaks of the histogram where the distance is maximum, the main scan image data may always be generated with one reading light.

  In addition, the printer 10 with an image reading sensor of the present embodiment includes a transport roller that transports the credit card C in the reverse direction toward the card insertion port 41a after transporting the credit card C in the forward direction from the card insertion port 41a. The image reading sensor 44 is configured to perform pre-scanning while the credit card C is conveyed in the forward direction, and to perform main scanning while the credit card C is conveyed in the reverse direction. Therefore, it is possible to perform a main scan during reverse transport after processing pre-scanned image data and selecting appropriate reading light using the time difference between forward transport and reverse transport. It is possible to realize an image reading process of a credit card C.

  Note that it is not necessary to use a special sensor as the image reading sensor 44 of this embodiment, and it is possible to use various general-purpose color image reading sensors.

  Further, the image reading sensor 44 of the present embodiment has been described as including three types of light sources of RGB, but the present invention is not limited to this. The white light source is decomposed into RGB using a filter or a dichroic mirror, and this decomposition is performed. Alternatively, the RGB light thus used may be used as reading light.

1 is an external perspective view showing a printer with an image reading sensor according to an embodiment of the present invention. It is a fragmentary sectional view of a printer with an image reading sensor. It is a perspective view which shows the upper surface cover part of a printer with an image reading sensor. It is sectional drawing which shows the upper surface side of the card conveyance path in an inner cover open state. It is a control block diagram of a printer with an image reading sensor of the present embodiment. It is a block diagram showing data processing for generating binarized image data inside a printer with an image reading sensor. It is the figure which represented typically the process by a histogram preparation part, (a) is a figure which represents typically RGB decomposition | disassembly and grayscale conversion of image data, (b) is the histogram produced for every RGB It is a graph which shows. It is a flowchart which shows the flow of the binarized image reading process in a printer with an image reading sensor. It is a block diagram which shows the data processing for the data generation inside the printer 10 with an image reading sensor. 4 is a flowchart showing a flow of gray scale image reading processing in the printer with an image reading sensor 10. (A) is the figure which looked at the credit card C from the surface, (b) is a schematic diagram which takes out and shows only the mark and design part of the credit card C, (c) is the character of the credit card C It is a figure which takes out and shows only an information description part.

Explanation of symbols

10. ・ Printer with image reading sensor 11. ・ Back side housing part 12. ・ Front side housing part 13. ・ Top cover part 40 ・ ・ Card image reading part 41 ・ ・ Card transport path 41a ・ ・ Card insertion slot 41b .. Overhang opening 42 .. Inner cover 43a .. First feed roller 43b .. First press roller 44 .. Card image reading sensor 45 .. Pressing roller 46a .. Second feed roller 46b .. Second press roller 48. Card detector 60. CPU 61. RAM 62. ROM 63. Stepping motor 64. Gate array 65. A / D converter 70. Binarized image generator 80. Gray scale image Generator

Claims (15)

An image reading sensor capable of reading a credit card conveyed on the card conveying path with a plurality of colors of reading light;
An image data generation unit that processes image data read by the image reading sensor;
The image data generation unit creates a histogram based on a prescan image obtained from the credit card by prescan, and drives the image reading sensor according to the histogram to perform a main scan. Credit card reader. The image data generation unit selects reading light that can acquire image data with the clearest contrast between the character part and the background part in the credit card according to the histogram,
The credit card reader according to claim 1, wherein the image reading sensor performs a main scan using the reading light. The image reading sensor performs the pre-scan using all of the reading lights of the plurality of colors,
The image data generation unit can create a histogram from the image data corresponding to each reading light, and obtain image data with the clearest contrast between the character part and the background part in the credit card while referring to each histogram. 3. The credit card reader according to claim 2, wherein the reading light is selected. The image data generation unit calculates a peak in each histogram created from image data corresponding to each reading light, performs a main scan using the reading light corresponding to the histogram having a maximum peak-to-peak distance,
4. The credit card reader according to claim 3, wherein the image data obtained by the main scan is transmitted to a host computer. The image data generation unit binarizes the image data obtained in the main scan to generate binarized image data,
5. The credit card reader according to claim 4, wherein the binarized image data is transmitted to the host computer. If the peak-to-peak distance of the histogram in which the peak-to-peak distance calculated based on the histogram respectively created from the image data corresponding to each reading light is smaller than a predetermined value, all the reading lights of the plurality of colors are To perform a main scan,
5. The credit card reader according to claim 4, wherein the image data obtained by the main scan is converted into grayscale image data and transmitted to the host computer. Furthermore, after transporting the credit card from the card insertion port in the forward direction along the card transport path, a transport roller for transporting the credit card in the reverse direction to the card insertion port along the card transport path,
7. The image reading sensor according to claim 1, wherein the image reading sensor performs the pre-scan while the credit card is conveyed in the forward direction, and performs a main scan while the credit card is conveyed in the reverse direction. The credit card reader according to any one of the above. The credit according to claim 1, wherein the image reading sensor is a color image reading sensor, and the plurality of reading lights are lights corresponding to R, G, and B, respectively. Card reader. Pre-scanning the credit card to obtain a pre-scan image;
Creating a histogram of the pre-scanned image;
A credit card reading method comprising: performing a main scan of the credit card according to the histogram. According to the histogram, further comprising the step of selecting any one of a plurality of colors of reading light capable of acquiring image data with the clearest contrast between the character portion and the background portion in the credit card,
The credit card reading method according to claim 9, wherein the main scan is performed using the selected reading light. The pre-scan is performed using all of the reading lights of the plurality of colors,
Create a histogram from the image data corresponding to each reading light,
11. One of the plurality of reading lights capable of acquiring image data having the clearest contrast between a character portion and a background portion in the credit card while referring to each histogram is selected. Credit card reading method. Calculating a peak in a histogram respectively created from image data corresponding to each reading light;
Performing a main scan using the reading light corresponding to a histogram having a maximum peak-to-peak distance;
The credit card reading method according to claim 11, further comprising: transmitting image data obtained by the main scan to a host computer. 13. The credit card reading method according to claim 12, further comprising the step of binarizing the image data obtained by the main scan to generate binarized image data. When the peak-to-peak distance of the histogram in which the peak-to-peak distance calculated based on the histogram respectively created from the image data corresponding to each reading light is smaller than a predetermined value, all of the plurality of reading lights are used. To perform the main scan,
13. The credit card reading method according to claim 12, wherein the image data obtained by the main scan is converted into grayscale image data and transmitted to the host computer. Performing the pre-scan while the credit card is transported in the forward direction along the card transport path, and performing the main scan while the credit card is transported in the reverse direction along the card transport path. The credit card reading method according to any one of claims 9 to 14.