Paper currency fold recognition apparatus and method

Patent metadata

Field	Value
Publication number	US-2017316632-A1
Application number	US-201515526103-A
Country	US
Kind code	A1
Filing date	Aug 20, 2015
Priority date	Nov 19, 2014
Publication date	Nov 2, 2017
Grant date	—

Abstract

Provided are a device and method for identifying a paper currency fold. The device includes: a transparent protective body, configured to maintain components in the device to be clean; a laser source, configured to emit laser light a rectangular grating, configured to modulate the laser light into stripes which changes to be bright or dark according to a certain rule on a surface of a paper currency; an area array photoelectric sensor, configured to capture an image; an imaging lens group, configured to converge an image of the surface of the paper currency onto the area array photoelectric sensor; and an information processing module electrically connected with the area array photoelectric sensor, configured to process an image signal captured by the area array photoelectric sensor.

First claim

1 . A device for identifying a paper currency fold, comprising:
a transparent protective body, configured to maintain components in the device to be clean; a laser source, configured to emit laser light; a rectangular grating arranged above the laser source, configured to modulate the laser light into stripes which changes to be bright or to be dark according to a certain rule on a surface of a paper currency; an area array photoelectric sensor, configured to capture an image; an imaging lens group arranged above the area array photoelectric sensor, configured to converge an image of the surface of the paper currency onto the area array photoelectric sensor; and an information processing module electrically connected with the area array photoelectric sensor, configured to process an image signal captured by the area array photoelectric sensor.

2 . The device for identifying the paper currency fold according to claim 1 , wherein the rectangular grating is driven to rotate by power.

3 . A method for identifying a paper currency fold, comprising:
step 1, receiving a to-be-detected paper currency transported from a note-transporting organization, and projecting laser light generated by a laser source into grating stripes which changes to be bright or to be dark according to a certain rule on the to-be-detected paper currency through a rectangular grating and a protective body; step 2, acquiring, by an area array photoelectric sensor, an image of the to-be-detected paper currency attached with the grating stripes through an imaging lens group, and obtaining a feature image of the grating stripes from the acquired image of the to-be-detected paper currency attached with the grating stripes; step 3, rotating the rectangular grating, changing a direction of the grating stripes projected on the to-be-detected paper currency by the laser source through the rectangular grating, repeating to perform step 2 to obtain the feature images of the grating stripes in n angles from the images of the to-be-detected paper currency attached with the grating stripes, with n being an integer more than or equal to 2; step 4, calculating, by an information processing module, a gradient changing cumulative value P of the feature images of the grating stripes in n angles along the directions of the grating stripes corresponding to the to-be-detected paper currency based on the feature images of the grating stripes in n angles of the to-be-detected paper currency; and step 5, determining whether a fold exists in the to-be-detected paper currency by comparing the gradient changing cumulative value P corresponding to the to-be-detected paper currency with a preset determining threshold T.

4 . The method for identifying the paper currency fold according to claim 3 , wherein obtaining the determining threshold T comprises:
step 1, receiving a circulated paper currency transported from the note-transporting organization, and projecting the laser light generated by the laser source into grating stripes which changes to be bright or to be dark according to a certain rule on the circulated paper currency through the rectangular grating and the protective body; step 2, acquiring, by the area array photoelectric sensor, an image of the circulated paper currency attached with the grating stripes through the imaging lens group, and obtaining a feature image of the grating stripes from the acquired image of the circulated paper currency attached with the grating stripes; step 3, rotating the rectangular grating, changing a direction of the grating stripes projected on the circulated paper currency by the laser source through the rectangular grating, repeating to perform step 2 to obtain the feature images of the grating stripes in n angles from the images of the circulated paper currency attached with the grating stripes, with n being an integer more than or equal to 2; step 4, calculating, by the information processing module, a gradient changing cumulative value S of the feature images of the grating stripes in n angles along the directions of the grating stripes corresponding to the circulated paper currency based on the feature images of the grating stripes in n angles of the circulated paper currency; step 5, performing, by the information processing module, step 1 to step 4 for each of U circulated paper currency samples to obtain the gradient changing cumulative value S a of the images of the grating stripes along the directions of the grating stripes corresponding to each of circulated paper currencies, wherein a=1, 2, . . . , U; and step 6, obtaining, by the information processing module, the determining threshold T for determining whether the fold exists by adopting at least one of a statistical analysis model and an artificial neural network learning and training method for the gradient changing cumulative value S a as a feature.

5 . The method for identifying the paper currency fold according to claim 4 , wherein the circulated paper currency refers to a paper currency sample can be normally circulated in accordance with a regulation of the People's Bank of China, and the grating stripes which changes to be bright or to be dark according to the certain rule refer to stripes generated by modulating the laser light by the rectangular grating.

6 . The method for identifying the paper currency fold according to claim 3 , wherein n is an integer more than or equal to 8, rotating angles of the rectangular grating are angles generated by evenly dividing a 360 degrees field into n-1 parts.

7 . The method for identifying the paper currency fold according to claim 3 , wherein the gradient changing cumulative value P or S of the feature images of the grating stripes in n angles along the directions of the grating stripes is calculated based on a following formula:

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Assignees

• Grg Banking Equipment Co Ltd

Inventors

• Luo Panfeng
• Liang Tiancai
• Jin Xiaofeng
• Zhang Yong

Classifications

• G06T7/521

  from laser ranging, e.g. using interferometry; from the projection of structured light · CPC title

• G06T2207/20084

  Artificial neural networks [ANN] · CPC title

• G06T2207/20076

  Probabilistic image processing · CPC title

• G06T2207/10152

  Varying illumination · CPC title

• G06T7/579

  from motion · CPC title