This application is the U.S. National Stage of international patent application number PCT/CN2012/083594, filed on Oct. 26, 2012 which claims the priority of Chinese Patent Application No. 201210049059.0, entitled “DEVICE AND METHOD FOR IDENTIFYING PAPER MEDIUM”, filed with the Chinese State Intellectual Property Office on Feb. 28, 2012, which applications are hereby incorporated by reference to the maximum extent allowable by law.
The invention relates to a technique for identifying a paper medium, and particularly to a device and method for identifying a paper medium such as paper currency.
An automated teller machine (ATM) in financial institution is mounted with a device for identifying a paper medium (such as paper currency). Template data for identifying a paper medium is stored in a storage part of the device for identifying the paper medium. Once the paper medium is loaded into the device for identifying the paper medium, an image data acquiring part of the device for identifying the paper medium is configured to read the paper medium optically, acquire grayscale image data of the paper medium to be identified, perform a match between the template and a detection result based on the obtained pattern and grayscale value of the grayscale image of the paper medium to be identified, and thus determine a kind and authenticity of the paper medium (currency).
If the device for identifying the paper medium has been used for a long time, a fault may occur in a certain light emitting element of the contact image sensor (CIS), or a transparent piece of the CIS may be dirty. Because the CIS performs a line scan, a black line with gray value approximate to 0 will occur on the reflected image or transmitted image acquired by the image sensor (which black line is referred to as “faulty line” hereinafter, and this case is referred to as “CIS faulty line phenomenon”), when a fault occurs in a certain light emitting element of the CIS or the transparent piece of the CIS is dirty. The position of a faulty light emitting element or dirty transparent piece of the CIS is random, so the position of the faulty line in the image of the paper medium to be detected is random. In this case, if the existing identification processes are performed, the acceptance rate of the device for identifying the paper medium will be decreased, the performance of the device and the customer experience will be affected significantly, and thus the marketing and application of the device will be obstructed.
Thus, it is necessary to propose a technique for effectively solving the problem of the CIS faulty line in the device for identifying the paper medium.
One of the objects of the invention is to provide a device for identifying a paper to medium, for effectively solving the problem of a CIS faulty line and improving the acceptance rate significantly.
A device and method for identifying a paper medium is further provided according to an embodiment of the invention.
A device for identifying a paper medium includes:
an image data acquiring part for acquiring original image data of the paper medium;
a faulty line detecting part for detecting whether there is a faulty line in the original image data of the paper medium obtained by the image data acquiring part, and obtaining a position of the faulty line if there is the faulty line in the original image data of the paper medium;
an image cutting part for cutting the original image data to obtain complete image information and identification image information of an effectively identified paper medium;
a standard template data storage part for storing a standard template for identifying the paper medium;
a comprehensive analysis part for comprehensively analyzing the complete image information of the paper medium, a result from the faulty line detecting part and data information of a standard template to determine whether the faulty line at a current position has influences template match identification;
a new template generating part for cutting the standard template into new sub-templates by taking the faulty line as a boundary based on an analysis result from the comprehensive analysis part in the case that the faulty line influences the template match identification, and performing no process on the standard template in the case that the faulty line does not influence the template match identification; and
a determining part for performing the template match identification on the identification image information of the paper medium by using the generated sub-templates and the template that is not influenced by the faulty line, to obtain an identification result.
Preferably, the image cutting part is further configured to cut the identification image to information with the faulty line based on the faulty line, so as to form identification sub-image information.
Further, the determining part is further configured to perform the template match identification between the identification sub-image information formed by the identification image information with the faulty line and the sub-template formed by the new template generating part to obtain an identification result.
The method for identifying the paper medium includes the following steps:
step 1, loading a paper medium to be identified, the paper medium entering into a transfer passage, and a process beginning;
step 2, scanning, by an image sensor, an image of the paper medium when the paper medium passes through a transfer passage, so as to form an original image;
step 3, setting, by a faulty line detecting part, the original image obtained by the image sensor in a coordinate system, and detecting whether there is a faulty line in the original image; the process going to step 4 if there is no faulty line in the original image, and further determining a position of the faulty line in the coordinate system if there is a faulty line in the original image;
step 4, cutting original image data to obtain complete image information and identification image information of the paper medium;
step 5, setting, by a comprehensive analysis part, the complete image information in a new coordinate system, determining a position of the faulty line in the new coordinate system, detecting whether the faulty line at a current position influences a template match identification according to data information of a standard template in a standard template data storage part, cutting a template that is influenced by the faulty line by taking the current faulty line as a boundary to generate a new sub-template, and performing no process on the standard template that is not influenced by the faulty line; and
step 6, performing the template match identification on the identification image information of the loaded paper medium by using the newly generated sub-template and the to template that is not influenced by the faulty line to obtain an identification result, and ending the process.
A method for detecting whether there is a faulty line in the original image in the step 3 is as follow:
assuming that:
(1) a grayscale value matrix of a reflected image has x0 columns and y0 rows;
(2) a grayscale value at a position of the yth row and the xth column in the reflected image is indicated by g(x, y); and
(3) an average grayscale value of the xth column in the reflected image is indicated by {tilde over (g)}(x);
in accordance with a constraint condition of:
an automatic search and detection is performed on an image grayscale matrix obtained by the image sensor; if the above constraint condition is met at a column of x=n0, that is, the n0th column in the image grayscale matrix, it is determined that there is a faulty line in the image; else, it is determined that there is no faulty line in the image.
A method for determining the position of the faulty line in the coordinate system xOy in the step 3 is as follow:
assuming that in a complete image of the paper medium, an upper left vertex is set as A, a lower left vertex is set as B, an upper right vertex is set as D and a lower right vertex is set as C, and the faulty line intersects with an upper boundary and a lower boundary of the to complete image of the paper medium at points E and F respectively, upper, lower, left and right boundary points of the complete image of the paper medium are detected, and a linear fit is performed for each of the obtained boundary points to obtain:
an upper boundary linear equation of: a1x+b1y+c1=0,
a lower boundary linear equation of: a2x+b2y+c2=0,
a left boundary linear equation of: a3x+b3y+c3=0, and
a right boundary linear equation of: a4x+b4y+c4=0;
by solving:
a coordinate of the upper left vertex A in the coordinate system xOy can be obtained, which is indicated by A(xa, ya);
by solving:
a coordinate of the lower left vertex B in the coordinate system xOy can be obtained, which is indicated by B(xb, yb); and
by solving:
coordinates of the points E and F in the coordinate system xOy can be obtained, which are indicated by E(xe, ye) and F(xf, yf) respectively,
resulting that:
dAB=√{square root over ((yb−ya)2+(xb−xa)2)}{square root over ((yb−ya)2+(xb−xa)2)},
dAE=√{square root over ((ye−ya)2+(xe−xa)2)}{square root over ((ye−ya)2+(xe−xa)2)}, and
dBF=√{square root over ((yf−yb)2+(xf−xb)2)}{square root over ((yf−yb)2+(xf−xb)2)}.
A method for determining the position of the faulty line in the coordinate system x′O′y′ in the step 5 is as follow:
the coordinate system x′O′y′ is established by taking the upper left vertex A as an origin, taking an extension direction of the upper boundary as the x axis, and taking a direction in which the left boundary extends as the y axis, and the coordinates of the points A, E and F are respectively:
O′=A=(0,0),
E=(dAE,0), and
F=(dBF,dAB);
and a linear equation of the faulty line EF in the coordinate system x′O′y′ is:
According to the invention, the method for cutting the template by taking the position of the faulty line as the boundary is adapted to generate a new sub-template from the standard template, and then a template match identification is performed between the newly generated sub-template and the identification image information of the paper medium to be identified, so that the influence of the faulty line on the template match identification is avoided, and the acceptance rate of the device for identifying the paper medium is improved.
Specific embodiments of the invention will be described hereinafter in conjunction with appended drawings, in order to further illustrate the invention.
The image data acquiring part 10 includes a transmissive sensor for detecting a transmitted image and/or a reflective sensor for detecting a reflected image. When the paper medium is transferred through the transfer passage, the image data acquiring part 10 acquires the transmitted image and/or the reflected image of the paper medium, and transfers the obtained transmitted image and/or reflected image to the faulty line detecting part 20.
The faulty line detecting part 20 detects whether there is a faulty line in the original image obtained by the image sensor at first, and accurately obtains the position of the faulty line in the whole image in the case that there is the faulty line in the original image of the loaded paper medium. Because the image is obtain by CIS in the rectilinear scanning, a black line with the grayscale value approximate to 0 occurs on the original image of the paper medium to be detected if there is any faulty line in the image. Because the position of the CIS faulty line has non-determinacy, the position of the faulty line in the original image of the paper medium to be detected also has non-determinacy. Assuming that when the faulty line (one faulty line) is detected by the CIS, the image obtained by the image sensor is shown as
If the image cutting and template match identification are performed directly without processing the faulty line region, the match can not be successful when the faulty line is exactly in a certain region on which the template match identification is to be performed, as shown in
In this embodiment, the faulty line is detected by using the reflected image of the loaded paper medium that is obtained by the reflective sensor. The reflected image of the loaded paper medium is set in the coordinate system xOy, as shown in
Assuming that:
(1) a grayscale value matrix of a reflected image has x0 columns and y0 rows;
(2) a grayscale value on a position of the yth row and the xth column in the reflected image is indicated by g(x, y); and
(3) an average grayscale value of the xth column in the reflected image is indicated by {tilde over (g)}(x),
in accordance with a constraint condition of:
for example, assuming that ε1=20, ε2=20, ε3=80 and ε4=80, automatic search and detection is performed on the grayscale value matrix of the reflected image obtained by the image sensor.
If there is no column x that meets the constraint condition (formula 1.1) by traversing the grayscale value matrix of the reflected image, it is determined that there is no faulty line in the reflected image obtained by the image sensor, and thus it can be deduced that there is no CIS faulty line in the device for identifying the paper medium. The process directly performs the step of cutting the complete image of the paper medium to be identified, and the template match identification is performed on the complete image of the paper medium obtained by cutting finally, to obtain a final identification result.
The image grayscale value matrix of the reflected image has a column of
x=n0,
that is, the n0th column of the image grayscale value matrix meets the above constraint condition (formula 1.1), and thus it is determined that there is the faulty line in the reflected image, i.e., the CIS faulty line phenomena in the device for identifying the paper to medium, and that the faulty line is located at the n0th column in the grayscale image obtained by the image sensor. Then, the image cutting process is processed.
In the coordinate system xOy, it is assumed that in the complete image of the paper medium, an upper left vertex is set as A, a lower left vertex is set as B, an upper right vertex is set as D and a lower right vertex is set as C, and the faulty line intersects with an upper boundary and a lower boundary of the complete image of the paper medium at points E and F respectively, as shown in
an upper boundary linear equation of: a1x+b1y+c1=0,
a lower boundary linear equation of: a2x+b2y+c2=0,
a left boundary linear equation of: a3x+b3y+c3=0, and
a right boundary linear equation of: a4x+b4y+c4=0,
By solving:
a coordinate of the upper left vertex A in the coordinate system xOy can be obtained, which is indicated by A(xa, ya).
By solving:
a coordinate of the lower left vertex B in the coordinate system xOy can be obtained, which is indicated by B(xb, yb).
By solving:
coordinates of the points E and F in the coordinate system xOy can be obtained, which are indicated by E(xe, ye) and F(xf, yf) respectively.
Based on the above, the result can be calculated:
dAB=√{square root over ((yb−ya)2+(xb−xa)2)}{square root over ((yb−ya)2+(xb−xa)2)},
dAE=√{square root over ((ye−ya)2+(xe−xa)2)}{square root over ((ye−ya)2+(xe−xa)2)}, and
dBF=√{square root over ((yf−yb)2+(xf−xb)2)}{square root over ((yf−yb)2+(xf−xb)2)}.
The coordinate system x′O′y′ is established by taking the upper left vertex A as an origin, taking an extension direction of the upper boundary as the x axis, and taking an extension direction of the left boundary as the y axis, as shown in
O′=A=(0,0),
E=(dAE,0), and
F=(dBF,dAB).
Thus, the linear equation of the faulty line EF in the coordinate system x′O′y′ is:
Based on the position of the faulty line in the coordinate system x′O′y′ (formula 1.2) and the standard template information stored in the standard template data storage part, the comprehensive analysis part detects whether there is a region to be matched that is influenced by the faulty line. If the faulty line has no influence on any of the regions to be matched (that is, the faulty line does not pass through any of the regions to be matched), the match to identification is performed directly without any other process. If the faulty line is exactly located in a certain region to be matched, as shown in
The method for generating the sub-template is shown in
Finally, the match identification is obtained by using the newly generated template and the template that is not influenced by the faulty line, to achieve the identification of the loaded paper medium, as shown in
According to the invention, with the method for cutting the template by taking the position of the faulty line as the boundary, a new sub-template is generated based on the standard template, and the template match identification is performed between the newly generated sub-template and the image of the paper medium to be identified, so that the influence of the faulty line on the template match identification is avoided, and the acceptance rate of the device for identifying the paper medium is improved.
The above are only preferred embodiments of the invention, and it is to be noted that the above preferred embodiments should not be interpreted as to limit the invention, and the scope of protection of the invention should be subject to the scope defined in the appended claims. Several modifications and variations can be made by those skilled in the art without deviating from the spirit and scope of the invention, which also fall within the scope of protection of the invention.
Number | Date | Country | Kind |
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2012 1 0049059 | Feb 2012 | CN | national |
Filing Document | Filing Date | Country | Kind |
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PCT/CN2012/083594 | 10/26/2012 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
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WO2013/127186 | 9/6/2013 | WO | A |
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6573983 | Laskowski | Jun 2003 | B1 |
8406527 | Kido | Mar 2013 | B2 |
20060263101 | Takamatsu et al. | Nov 2006 | A1 |
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1196633 | Mar 2004 | CN |
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Entry |
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Zhang, Dongjiao et al. Research on RMB Currency Number Identification System Based on Template Matching, Computer & Digital Engineering, Jan. 2012, vol. 40, No. 1, pp. 104-108, ISSN 1672-9722. |
International Search Report dated Jan. 24, 2013 from corresponding International Application No. PCT/CN2012/083594. |
Number | Date | Country | |
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20140126803 A1 | May 2014 | US |