JP2002015304A - Print detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reliably detect the prints of a passbook or the like with a color image sensor. SOLUTION: A reference medium printed with characters in the density of a decision criterion is read by the color image sensor 11 and converted into R, G, B data of digital values by ADC(analog-to-digital converters) 12a-12c. The maximum level value MAX for every picture element is detected by a maximum value detecting circuit 14, and an achromatic color/color decision is made by a color decision circuit 15. The frequency distribution of the achromatic color picture element density is generated by a frequency distribution generating circuit 22, and a reference value slice is decided based on this frequency distribution and registered on a flash memory 19. The image of the passbook 2 is read by the color image sensor 11, and the density of the achromatic color picture elements is compared with the reference value slice by a CPU 20 to detect the presence or absence of the prints on the passbook 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a print detecting device for detecting a printed line or the like in a bankbook or the like.

[0002]

2. Description of the Related Art FIG. 2 is a block diagram showing an example of a conventional optical character reading device (hereinafter referred to as "OCR"). This OCR irradiates the form 1 to be read with visible light,
It has a color image sensor 11 that separates the image of the reading area into pixels and detects the levels of red (R), green (G), and blue (B) reflected light. Output signals r, g, b of analog voltage output from color image sensor 11
Are analog / digital conversion circuits (hereinafter, referred to as
(Referred to as "ADC") 12a, 12b, and 12c. The ADCs 12a to 12c convert the output signals r, g, and b into digital values, respectively.

[0005] The output sides of the ADCs 12a to 12c are connected to a correction circuit 13 for performing black and white level correction. The output side of the correction circuit 13 is connected to a maximum value detection circuit 14 and a color determination circuit 15. The maximum value detection circuit 14 detects the maximum value MAX of the R, G, and B data of each pixel corrected and output by the correction circuit 13. Further, the color determination circuit 15 determines whether each pixel is a chromatic color or an achromatic color based on the color difference (that is, the difference between the R, G, and B data) to determine the color information C.
OL is output.

The outputs of the maximum value detection circuit 14 and the color judgment circuit 15 are connected to the image memory 1 via a data alignment circuit 16.
7 is connected. The data alignment circuit 16 aligns the maximum value MAX and the color information COL for each pixel, and stores them in the image memory 17. The image memory 17 is connected to a system bus 18. The system bus 18 has a flash memory 19 in addition to the image memory 17.
And a central processing unit (hereinafter, referred to as “CPU”) 20. The flash memory 19 holds various parameters such as threshold values for identifying pixels constituting characters and the like. The CPU 20 stores the image memory 1
7 is compared with a threshold value held in the flash memory 19 to determine whether or not a print character exists in the read area, and to recognize the print character that exists.

In such an OCR, the image of the form 1 to be read is read by the color image sensor 11 into R, G, B
The ADCs 12a-1
After being converted into a digital value in 2c, a level correction is performed in the correction circuit 13. The corrected R, G, B data is
The maximum value detection circuit 14 detects the maximum value MAX for each pixel, and the color determination circuit 15 determines whether the pixel is chromatic or achromatic, and outputs color information COL. The maximum value MAX and the color information COL for each pixel are aligned by the data alignment circuit 16 and sequentially stored in the image memory 17 as image data.

After the image data in the read area is stored in the image memory 17, the image data is read out by the CPU 20 and compared with a threshold value stored in the flash memory 19 in advance to detect a character or to detect the detected character. Recognition is performed.

[0007]

However, the conventional OCR has the following problems. If the show-through of a relatively dark print and the copy-forgery-inhibited pattern overlap, such as in a bankbook, the level difference between the printed character and the show-through + copy-forgery-inhibited pattern becomes small, making it difficult to detect the line on which the character is printed. Become.
In particular, when the printing ink is thin, there is a problem that printed lines cannot be identified. For this reason, for example, in a device that reads a form or passbook, such as a bank terminal, in addition to a color sensor for reading characters and imprints of the form, an infrared ray is used to reliably detect a page mark or a printed line of the passbook. There is a problem that the sensor is used in combination and the scale of the device becomes large.

The present invention solves the problems of the prior art, and provides a print detection device capable of detecting a print on a passbook or the like using a color image sensor.

[0009]

According to a first aspect of the present invention, there is provided a color image sensor for reading an image of an image by separating the image into pixels for each color. A color determining means for identifying achromatic pixels and chromatic pixels from the image read by the color image sensor; and Means for generating a reference value for the print density based on the frequency distribution of the pixel density of the reference medium determined to be achromatic by the means; achromatic color read by the color image sensor and achromatic by the color determination means; A print determination unit that determines the presence or absence of printing by comparing the determined density of the pixels forming the image of the passbook to be read with the determination reference value.

According to the first aspect of the present invention, since the print detecting device is configured as described above, the following operation is performed. First, a reference medium on which printing is performed at a density serving as a criterion for determining the presence or absence of printing is read by a color image sensor, and a criterion value generating unit generates a criterion value based on a frequency distribution of pixel densities.

Next, the passbook to be read is read by the color image sensor, and the density of the pixels which have been determined to be achromatic by the color determining means among the read pixels is compared with a determination reference value by the print determining means. You. Thereby, the presence or absence of printing is determined.

According to a second aspect of the present invention, in the print detection device according to the first aspect, the copy-forgery-inhibited pattern of the passbook based on the frequency distribution of the pixel density of the passbook read by the color image sensor and determined to be chromatic by the color determination means. And a reference value correcting means for correcting the determination reference value based on the detected density of the copy-forgery-inhibited pattern. Further, the print determination means is configured to determine whether or not the passbook is printed according to the determination reference value corrected by the reference value correction means.

According to the second aspect, the following operation is performed. First, a reference medium on which printing is performed at a density serving as a criterion for determining the presence or absence of printing is read by a color image sensor, and a criterion value generating unit generates a criterion value based on a frequency distribution of pixel densities.

Next, the passbook to be read is read by the color image sensor, and the color of the read pixel is determined by the color determination means. The reference value correction means detects the density of the copy-forgery-inhibited pattern of the passbook based on the density of the pixel determined to be chromatic, and corrects the determination reference value based on the detected density. The print determination unit determines whether the passbook is printed based on the corrected determination reference value.

According to a third aspect of the present invention, the reference value correcting means according to the second aspect of the present invention uses the reference value correction means based on the frequency distribution of the pixel density of each passbook color read by the color image sensor and determined to be chromatic by the color determination means. The density of the copy-forgery-inhibited pattern in the passbook is detected for each color, and the determination reference value is corrected based on the detected density of the copy-forgery-inhibited pattern for each color.

According to the third invention, the following operation is performed. First, a reference medium on which printing is performed at a density serving as a criterion for determining the presence or absence of printing is read by a color image sensor, and a criterion value generating unit generates a criterion value based on a frequency distribution of pixel densities.

Next, the passbook to be read is read by the color image sensor, and the color of the read pixel is determined by the color determination means. The reference value correction means detects the density of the copy-forgery-inhibited pattern of the passbook based on the density of each color of the pixel, and corrects the determination reference value based on the detected density. The print determination unit determines whether the passbook is printed based on the corrected determination reference value.

According to a fourth aspect of the present invention, the reference value correcting means according to the second or third aspect calculates a frequency distribution of the pixel density of the copy-forgery-inhibited pattern of the passbook based on an area signal for dividing the passbook reading area. The determination reference value is corrected in accordance with the frequency distribution for each of the regions.

According to the fourth invention, the following operation is performed in the reference value correcting means of the second or third invention. For example, from the passbook transport mechanism to the reference value correction means,
When an area signal that divides the passbook reading area is given, the frequency distribution of the pixel density of the copy-forgery-inhibited pattern of the passbook is calculated based on the area signal. The correction of the determination reference value is performed for each of the divided areas according to the calculated frequency distribution.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 is a configuration diagram of a print detection device showing a first embodiment of the present invention, and the same elements as those in FIG. Reference numerals are given. This print detection device irradiates the passbook 2 to be read with visible light, decomposes the image of the read area into pixels,
It has a color image sensor 11 that detects the levels of the red (R), green (G), and blue (B) reflected light. The output signal r of the analog voltage of the color image sensor 11,
g and b are provided to the ADCs 12a, 12b, and 12c, respectively. ADCs 12a to 12c are:
The output signals r, g, and b corresponding to the R, G, and B components of the reflected light are converted into digital values.

The output sides of the ADCs 12a to 12c are connected to a correction circuit 13 for correcting white and black levels.
The output side of the correction circuit 13 is connected to a maximum value detection circuit 14 and a color determination means (for example, a color determination circuit) 15. The maximum value detection circuit 14 detects the maximum value MAX of the R, G, and B data for each pixel corrected and output by the correction circuit 13. The color determination circuit 15 determines whether each pixel is a chromatic color or an achromatic color based on the color difference, and outputs color information CO.
L is output.

The outputs of the maximum value detecting circuit 14 and the color judging circuit 15 are connected to the image memory 1 via a data aligning circuit 16.
7 is connected. The data alignment circuit 16 aligns the maximum value MAX and the color information COL for each pixel, and stores them in the image memory 17 as image data. The image memory 17 is connected to a system bus 18. A frequency distribution memory 21 is connected to the system bus 18 in addition to a flash memory 19, a print determination unit and a reference value correction unit (for example, a CPU) 20.

The flash memory 19 has a threshold value such as a reference value (for example, a reference value slice) for identifying a pixel constituting a character or the like, a correction value table for correcting the threshold value in accordance with a tint block density, and the like. Is a non-volatile memory that stores various parameters. The CPU 20 compares each pixel of the image data stored in the image memory 17 with a threshold value stored in the flash memory 19 to determine whether or not a character printed in the read area exists, and Various processes and control such as correction of a value slice are performed.

Further, the maximum value detection circuit 14 and the color judgment circuit 1
5 is connected to a reference value generating means (for example, a frequency distribution generating circuit) 22.
The frequency distribution memory 21 and the area switching circuit 23 are connected. The frequency distribution generation circuit 22 generates a histogram of the maximum value MAX of each pixel in the read area based on the maximum value MAX given from the maximum value detection circuit 14 and the color information COL given from the color determination circuit 15. It is.

The area switching circuit 23 outputs a switching signal SEL for controlling the switching of the area for generating the frequency distribution to the frequency distribution generating circuit 22 in accordance with an area signal given from, for example, a passbook transport mechanism (not shown). is there.
The histogram generated by the frequency distribution generation circuit 22 is stored in the frequency distribution memory 21.

FIGS. 3A to 3C are explanatory diagrams of the print detection processing operation shown in FIG. Hereinafter, FIG.
With reference to (c), the operation of FIG. 1 will be described separately for (A) processing at the time of adjustment and (B) processing at the time of operation.

(A) Processing for Adjustment A "reference medium" is prepared on a white passbook on which a copy-forgery-inhibited pattern is not printed, in which characters of a lower density to be recognized as black and characters of an upper density to be recognized as white are printed. Then, the reference medium is read by the color image sensor 11. The output signals r, g, b of the color image sensor 11 are
After being converted into a digital value by c, the level correction is performed by the correction circuit 13. From the corrected R, G, B data, the maximum value MAX is detected for each pixel by the maximum value detection circuit 14, and the color determination circuit 15 determines whether the pixel is a chromatic color or an achromatic color. Is output. The maximum value MAX and the color information COL for each pixel are provided to the frequency distribution generation circuit 22.

In the frequency distribution generating circuit 22, as shown in FIG. 3A, the maximum value MA detected by the maximum value detecting circuit 14 is determined for the pixel determined to be achromatic by the color determining circuit 15.
A histogram of the X level (gradation) is generated and stored in the frequency distribution memory 21. Further, the frequency distribution memory 21
Are detected from the achromatic histogram stored in the flash memory 19, the gradation of the boundary between the lower density character to be recognized as black and the upper density character to be recognized as white is determined, and the reference value slice is determined and registered in the flash memory 19. .

(B) Processing during Operation When the passbook 2 to be read is read by the color image sensor 11, the output signals r, g, b of the color image sensor 11 are converted into digital values by the ADCs 12a to 12c. Thereafter, the level correction is performed by the correction circuit 13. The corrected R, G, B data is output to the maximum value detection circuit 1
At 4, the maximum value MAX is detected. Further, the color determination circuit 15
In, color information COL of chromatic color or achromatic color is output based on the difference between the R, G, and B data for each pixel. The maximum value MAX and the color information COL for each pixel are provided to the data alignment circuit 16 and the frequency distribution generation circuit 22. Data alignment circuit 16
Then, for each pixel, the maximum value MAX and the corresponding color information C
OL and the image memory 1 as image data.
7 are sequentially stored.

On the other hand, the frequency distribution generating circuit 22 generates a histogram of the level of the maximum value MAX. At this time,
In the frequency distribution generation circuit 22, the area is switched according to the switching signal SEL given from the area switching circuit 23.
For example, in the form 2 in FIG. 1, there are three types of a page mark at the top of each page, an area X in which a dark background pattern is printed in a print line, and an area Y in which a light background pattern is printed. Switch to the area. Thereby, the frequency distribution generation circuit 2
In 2, a histogram is generated for each of the three regions divided for each switched region.

As shown in FIGS. 3B and 3C, a chromatic color histogram and an achromatic color histogram are separately generated based on the color information COL, and are stored in the frequency distribution memory 21. After the passbook 2 is read, the CPU 20 reads a chromatic histogram in the frequency distribution memory 21 for each area, and detects the maximum density MAX of the tint block color density as shown in FIG. 3B. You.
Further, the CPU 20 refers to the correction value table held in the flash memory 19, and corrects the reference value slice by the correction value corresponding to the copy-forgery-inhibited pattern density.
A value slice (= reference value slice−correction value) is calculated.

Thereafter, the maximum value MAX of the image data stored in the image memory 17 is compared with the binarized slice calculated by the CPU 20 for each pixel. If the maximum value MAX is equal to or less than the reference value slice, it is determined as black, and if the maximum value MAX exceeds the reference value slice, it is determined as white.
Valued. At this time, since the density of the copy-forgery-inhibited pattern of the passbook 2 is equal to or more than the binarized slice, it becomes white. Further, based on the data binarized for each pixel, the CPU 20 determines whether or not there is printing for each line.

As described above, the print detection device of the first embodiment has the following advantages (1) to (3). (1) A frequency distribution generating circuit 22 and a frequency distribution memory 21 are provided, and a reference value slice serving as a character detection reference is determined from a histogram generated based on a “reference medium” at the time of adjustment. This makes it possible to detect the presence or absence of a character printed on a dark copy-forgery-inhibited pattern from image data obtained from the color image sensor 11 without using an infrared sensor.

(2) The CPU 20 calculates the binarized slice by correcting the reference value slice based on the density of the copy-forgery-inhibited pattern obtained from the chromatic color histogram. This makes it possible to more reliably detect the presence or absence of a printed character without being affected by the density of the tint block.

(3) The passbook 2 to be read is divided into areas having different shades of page marks and copy-forgery-inhibited patterns, and an area switching circuit 23 for generating respective histograms is provided. This makes it possible to reliably detect print characters and page marks corresponding to various passbooks.

(Second Embodiment) FIG. 4 shows a second embodiment of the present invention.
FIG. 2 is a configuration diagram of a print detection apparatus according to the first embodiment, in which elements common to those in FIG. 1 are denoted by common reference numerals. The difference between the print detection device of this embodiment and the print detection device of FIG. 1 is that the print detection device of FIG.
While the histogram is generated based on the maximum value MAX of the data, the print detection apparatus generates a histogram for each of R, G, and B data.

That is, this print detection apparatus includes three sets of frequency distribution generating circuits 22a, 22b, 22c and three sets of frequency distribution memories 21a, 21b, 21c. Each of the frequency distribution generation circuits 22a to 22c has R,
The B and G data are respectively supplied, and the color information COL is commonly supplied from the color determination circuit 15. The frequency distribution generation circuits 22a to 22c are connected to frequency distribution memories 21a to 21c for storing the generated histograms, respectively. These frequency distribution memories 21a to 21c are connected to the system bus 18. Other configurations are the same as those in FIG.

In such a print detection device, when a form to be read is read by the color image sensor 11, the image data of the read area is stored in the image memory 1.
7, and a chromatic histogram for each of the R, G, B data is generated by the frequency distribution generation circuits 22a to 22c, and stored in the frequency distribution memories 21a to 21c, respectively.

After the reading of the form is completed, the CPU 20 calculates the R, G, and B data from the chromatic color histogram for each of the R, G, and B data.
The maximum value of the tint block density is detected. The tint block color and shading are recognized based on the tint block density for each of the R, G, and B data, and the respective color differences, whereby the correction value table previously stored in the flash memory 19 is referred to, and the correction corresponding to the tint block density is performed. The reference value slice is corrected by the value to 2
A value slice is calculated.

Thereafter, the maximum value MAX of the image data stored in the image memory 17 and the binarized slice
The comparison is performed for each pixel by U20, and the image data is binarized. Further, the CPU 20 determines the presence or absence of printing for each line based on the binarized data for each pixel.

As described above, the print detection device according to the second embodiment uses the frequency distribution generation circuit 2 for each of R, G, and B data.
2a to 22c and frequency distribution memories 21a to 21c. As a result, in addition to the advantages of the above (1) and (2), it is possible to further cope with various copy-forgery-inhibited patterns of a passbook, and there is an advantage that the detection accuracy of printed characters can be further improved.

Note that the present invention is not limited to the above embodiment, and various modifications are possible. For example, there are the following modifications (a) to (c). (A) The print detection device of FIG. 1 has an area switching circuit 23 for generating a histogram while distinguishing a plurality of areas having different tint block densities. If a passbook with a small difference is to be read, the area switching circuit 23 may be deleted.

(B) The CPU 20 detects the maximum value MAX of the tint block color density from the chromatic color histogram stored in the frequency distribution memory 21, and corrects the reference value slice with the correction value corresponding to the tint block density. Although the binarized slice is calculated by the above, this process may be omitted when the actual correction value is not so large.

(C) The print detection device shown in FIGS.
Although the presence or absence of a print character is detected by the CPU 20, it is also possible to configure such that when a print character is detected, the character is recognized. That is,
The processing described in the above embodiment can be applied as preprocessing of the character recognition processing and the mark reading processing. This makes it possible to accurately recognize characters and marks printed on the copy-forgery-inhibited pattern.

[0045]

As described above in detail, according to the first aspect, there is provided the reference value generating means for generating the determination reference value based on the frequency distribution of the pixel density of the reference medium read by the color image sensor. are doing. Further, it has a color determination means for determining achromatic pixels among the pixels of the passbook read by the color image sensor. Thus, by comparing the density of the achromatic pixels of the passbook with the determination reference value, printing on the passbook or the like can be detected.

According to the second invention, there is provided a reference value correcting means for correcting the determination reference value based on the density of the copy-forgery-inhibited pattern of the passbook. Thereby, even if the density of the copy-forgery-inhibited pattern is high, printing on a passbook or the like can be detected.

According to the third invention, there is provided a reference value correcting means for correcting the determination reference value based on the density of each copy-forgery-inhibited pattern of the passbook. This makes it possible to more reliably detect a print on a passbook or the like without being influenced by the color or density of the copy-forgery-inhibited pattern.

According to the fourth aspect, there is provided a reference value correcting means for obtaining a correction value for each passbook area and correcting the determination reference value based on the correction value. As a result, printing can be reliably detected even in a passbook having regions with different tint block colors and densities.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a print detection device according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram illustrating an example of a conventional OCR.

FIG. 3 is an explanatory diagram of a print detection processing operation according to FIG. 1;

FIG. 4 is a configuration diagram of a print detection apparatus according to a second embodiment of the present invention.

[Explanation of symbols]

2 Passbook 11 Color Image Sensor 12a-12c ADC (Analog / Digital Conversion Circuit) 14 Maximum Value Detection Circuit 15 Color Judgment Circuit 16 Data Alignment Circuit 17 Image Memory 19 Flash Memory 20 CPU (Central Processing Unit) 21, 21a-21c Frequency Distribution Memory 22, 22a to 22c Frequency distribution generation circuit 23 Area switching circuit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 1/60 G07D 9/00 436 5C079 1/46 H04N 1/40 D 5L096 // G07D 9/00 436 1 / 46 Z (72) Inventor Masaji Mataga 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd. F-term (reference) 2C087 AA14 BA03 BA07 BB10 BD53 2G020 AA08 DA05 DA13 DA32 DA43 3E040 AA07 FH05 FK05 5B057 AA11 BA30 DA20 DB02 DB05 DB06 DB09 DC19 DC25 5C077 MP08 PQ19 RR14 TT10 5C079 HB01 LA34 MA10 NA29 PA00 5L096 AA02 AA06 BA17 CA02 EA35 FA15 FA37 FA44 GA51 JA11

Claims (4)

[Claims] 1. A color image sensor for reading an image of an image by separating the image into pixels for each color; a color determination unit for identifying achromatic and chromatic pixels from the image read by the color image sensor; A print density is determined by the color image sensor and printed by the color image sensor, and a print density determination reference value is generated based on a frequency distribution of pixel density of the reference medium determined to be achromatic by the color determination unit. A reference value generating unit, comparing the density of pixels constituting an image of the passbook to be read, which is read by the color image sensor and determined to be achromatic by the color determining unit, with the determination reference value, and determines whether or not printing is performed. And a print determination means for determining whether or not the print condition is satisfied. 2. A density of a copy-forgery-inhibited pattern of the passbook is detected based on a frequency distribution of pixel densities of the passbook read by the color image sensor and determined to be chromatic by the color determination unit, and the density of the detected copy-forgery-inhibited pattern is detected. A reference value correction unit that corrects the determination reference value based on the reference value is provided, and the print determination unit is configured to determine whether the passbook is printed according to the determination reference value corrected by the reference value correction unit. The print detection device according to claim 1, wherein: 3. The reference value correction means, based on a frequency distribution of pixel densities for each color of the passbook read by the color image sensor and determined to be chromatic by the color determination means, 3. The print detecting apparatus according to claim 2, wherein a density is detected for each color, and the determination reference value is corrected based on the detected density for each color of the tint block. 4. The reference value correction means calculates a frequency distribution of pixel densities of a tint block of the passbook based on an area signal dividing the passbook reading area, and for each of the divided areas, according to the frequency distribution. 4. The print detection device according to claim 2, wherein the determination reference value is corrected.