Paper currency number recognition apparatus and recognition method

• US 9,741,193 B2
• Filed: 07/05/2013
• Issued: 08/22/2017
• Est. Priority Date: 11/15/2012
• Status: Expired due to Fees

• Current Assignee: GRG Banking Equipment Company Limited (City of Guangzhou)
• Original Assignee: GRG Banking Equipment Company Limited (City of Guangzhou)
• Inventors: Chen, Zhuwen, Liu, Mengtao
• Primary Examiner(s): YANG, WEI WEN
• Application Number:
  US14/426,972
• Publication Number:
  US 20150279141A1
• Time in Patent Office: 1,509 Days
• Field of Search: None
• CPC Class Codes: G07D 7/0047 using checkcodes, e.g. coded numbers derived from serial number and denomination
• CPC Class Codes: G07D 7/12 Visible light, infrared or ultraviolet radiation
• CPC Class Codes: G07D 7/121 Apparatus characterised by sensor details

Abstract

A paper currency number recognition apparatus and method. The apparatus comprises: a contact-type sensor (10) for acquiring paper currency image data; a white-light LED transmission light source board (20); an image acquisition processing board (40) which is integrated with an FPGA and a DSP, the FPGA being used for controlling ON/OFF of the white-light LED transmission light source board (20) and driving the contact-type sensor (10) to acquire an image, and the DSP being used for processing and recognizing the paper currency image data; and two pairs of position sensors (30) for detecting whether there is a paper currency entering the paper currency number recognition apparatus, wherein the white-light LED transmission light source board (20) has two light source modes which are strong and weak, and the two light source modes alternately provide a transmission light source for the contact-type sensor (10) to acquire the paper currency image data. The apparatus can acquire two white-light transmission images with different brightness of one and the same paper currency each time; therefore, the numbers of both new and old paper currencies can be effectively recognized, and the accuracy rate of paper currency number recognition is improved.

Claims

1. A paper currency number recognition device, comprising:

a contact sensor configured to acquire paper currency image data by way of transmission imaging;

a white light LED transmission light source board arranged right in front of the contact sensor to provide the contact sensor with a transmission light source for use in collecting the paper currency image data;

an image collection processing plate connected to the contact sensor through a data cable, wherein a Field Programmable Gate Array and a digital signal processor are integrated on the image collection processing plate, the Field Programmable Gate Array is configured to control the white light LED transmission light source board to be on or off and drive a CIS to acquire images, and the digital signal processor is configured to process and recognize the paper currency image data; and

two pairs of position sensors arranged on a paper currency transport pathway at a position with a predetermined distance from the contact sensor and configured to detect whether there is a paper currency entering the paper currency number recognition device;

wherein the white light LED transmission light source board has a strong light mode and a weak light mode, and the two light modes alternately provides the contact sensor with the transmission light source for use in collecting the paper currency image data, and

wherein, after the Field Programmable Gate Array completes collection of a row of image data, the Field Programmable Gate Array informs the digital signal processor in a manner of an interruption of acquiring data, and the digital signal processor enters an interrupt service routine and detects an image type register to determine a type of the row of image data.

2. The paper currency number recognition device according to claim 1, wherein the two light modes are formed by controlling turn-on time of the white light LED transmission light source board by the Field Programmable Gate Array, the strong light mode is formed in a case that the turn-on time is longer, the weak light mode is formed in a case that the turn-on time is shorter, and the ratio between the turn-on time for forming the strong light mode and the turn-on time for forming the weak light mode is 3:

1.

3. The paper currency number recognition device according to claim 1, wherein a memory is integrated on the image collection processing plate, the memory comprises two buffers and the register, the buffers are configured to store the paper currency image data collected by the contact sensor, and the register is configured to indicate a type of the paper currency image data in the buffers, with 1 indicating strong light image data and 0 indicating weak light image data.

4. The paper currency number recognition device according to claim 1, wherein a clock MCLK with a cycle of 0.125 ms and a row counter are provided inside the Field Programmable Gate Array.

5. A paper currency number recognition method, comprising:

step 1 comprising acquiring strong light image data and weak light image data of a paper currency by way of transmission imaging in the case that a transmission light source irradiates alternately in a strong light mode and in a weak light mode;

step 2 comprising performing an edge detection on the weak light image data to acquire four edges of an image to determine a target image;

step 3 comprising processing the target image to recognize a version, a nominal value, an orientation of the paper currency and determine an area where the paper currency number is located;

step 4 comprising calling a pattern recognition algorithm, comparing a gray value of the paper currency image with a threshold value by using a pattern recognition method based on artificial neural networks to recognize that the paper currency is new or old, and using the strong light image data for recognition in the case of an old paper currency, or selecting the weak light image data for recognition in the case of a new paper currency; and

step 5 comprising outputting a recognition result of the paper currency number,

wherein, after the Field Programmable Gate Array completes collection of a row of image data, the Field Programmable Gate Array informs the digital signal processor in a manner of an interruption of acquiring data, and the digital signal processor enters an interrupt service routine and detects an image type register to determine a type of the row of image data.

6. The paper currency number recognition method according to claim 5, wherein four vertex coordinates of the paper currency image are acquired, slope-a slopes of lines at which borders of the paper currency is located is computed by using a least square line fitting method, and four edges of the image are acquired, in step 2.

7. The paper currency number recognition method according to claim 5, wherein acquiring strong light image data and weak light image data of a paper currency in step 1 comprises:

step 101 comprising detecting a state of a position sensor;

step 102 comprising judging whether the position sensor is triggered, proceeding to step 103 in the case that the position sensor is triggered, or returning to step 101 in the case that the position sensor is not triggered;

step 103 comprising starting to scan to acquire the paper currency image data, resetting a row counter, and proceeding to step 104;

step 104 comprising detecting a rising edge of a MCLK;

step 105 comprising judging whether the rising edge of the MCLK is detected, proceeding to step 106 in the case that the rising edge of MCLK is detected, or returning to step 104 in the case that the rising edge of MCLK is not detected;

step 106 comprising switching a LED for strong light irradiation;

step 107 comprising driving, by a FPGA, a CIS to collect a row of image data, and proceeding simultaneously to step 108 and step 120, wherein step 108 and subsequent steps of step 108 are performed in parallel with step 120 and subsequent steps of step 120;

step 108 comprising detecting the rising edge of the MCLK again;

step 109 comprising judging whether the rising edge of the MCLK is detected, proceeding to step 110 in the case that the rising edge of the MCLK is detected, or returning to step 108 in the case that the rising edge of the MCLK is not detected;

step 110 comprising switching the LED for weak light irradiation;

step 111 comprising driving, by the FPGA, the CIS to collect a row of image data again, and proceeding simultaneously to step 112 and step 120, wherein step 112 and subsequent steps of step 112 are performed in parallel with step 120 and subsequent steps of step 112;

step 112 comprising adding 2 to the row counter in the FPGA;

step 113 comprising judging whether the count of the row counter in FPGA is equal to 960, proceeding to step 114 in the case that the count of the row counter in FPGA is equal to 960, or returning to step 104 in the case that the count of the row counter in FPGA is not equal to 960;

step 114 comprising completing image collection and ending scan;

step 120 comprising a DSP entering an interrupt service routine;

step 121 comprising detecting the image type register;

step 122 comprising judging whether the image data is strong light image data, proceeding to step 123 in the case that the image data is strong light image data, or proceeding to step 124 in the case that the image data is not strong light image data;

step 123 comprising storing a row of data into a strong light image buffer; and

step 124 comprising storing a row of data into a weak light image buffer.