Systems and methods for detecting tape on a document

• US 8,749,767 B2
• Filed: 08/31/2010
• Issued: 06/10/2014
• Est. Priority Date: 09/02/2009
• Status: Active Grant

• Current Assignee: Cash Processing Solutions, Inc. (De La Rue PLC)
• Original Assignee: Cash Processing Solutions, Inc. (De La Rue PLC)
• Inventors: Parkov, Alexander, Blair, Ronald Bruce
• Primary Examiner(s): Repko, Jason M
• Assistant Examiner(s): ROWLAND, JHERE M
• Application Number:
  US12/872,960
• Publication Number:
  US 20110052082A1
• Time in Patent Office: 1,379 Days
• Field of Search: None
• US Class Current: 356/57
• CPC Class Codes: G06V 10/143 Sensing or illuminating at different wavelengths
• CPC Class Codes: G06V 30/418 Document matching, e.g. of document images
• CPC Class Codes: G07D 7/1205 Testing spectral properties
• CPC Class Codes: G07D 7/121 Apparatus characterised by sensor details
• CPC Class Codes: G07D 7/189 Detecting attached objects, e.g. tapes or clips G07D7/187 takes precedence
• CPC Class Codes: G07D 7/202 using pattern matching

Abstract

Systems and methods for detecting tape on a document are provided. In one embodiment, a method includes capturing a first image of a document. The first image is captured while at least a portion of the document is subjected to a first electromagnetic radiation. The method includes capturing a second image of the document. The second image is captured while at least a portion of the document is subjected to a second electromagnetic radiation. The method also includes comparing the first image to the second image to determine whether tape is adhered to the document.

Claims

1. A method for detecting tape on a document, the method comprising:

capturing a first image of a document, the first image captured while at least a portion of the document is subjected to a first electromagnetic radiation;

capturing a second image of the document, the second image captured while at least a portion of the document is subjected to a second electromagnetic radiation; and

comparing the first image to the second image to determine whether tape is adhered to the document;

wherein capturing the first image of the document comprises capturing a first plurality of line images of the document to form the first image, and wherein capturing the second image of the document comprises capturing a second plurality of line images of the document to form the second image, and

wherein each line image is an image of a vertically spread line of sight of a segment of the document that is less than a whole of the document.

2. The method of claim 1, wherein each of the first electromagnetic radiation and the second electromagnetic radiation is one of ultraviolet light, white light, or specular reflected white light.

3. The method of claim 1, wherein capturing the first and second images further comprises combining the first and second pluralities of line images to form an interleaved image of the document, and separating the interleaved image into the first image and the second image.

4. The method of claim 1, further comprising:

capturing a third image of the document, the third image captured while the document is subjected to a third electromagnetic radiation; and

wherein comparing the first image to the second image to determine whether tape is adhered to the document comprises comparing the first image, the second image, and the third image to determine whether tape is adhered to the document.

5. The method of claim 4, wherein each of the first electromagnetic radiation, the second electromagnetic radiation, and the third electromagnetic radiation is one of ultraviolet light, white light, or specular reflected white light.

6. The method of claim 4, wherein capturing the first image of the document comprises capturing a first plurality of line images of the document to form the first image;

wherein capturing the second image of the document comprises capturing a second plurality of line images of the document to form the second image; and

wherein capturing the third image of the document comprises capturing a third plurality of line images of the document to form the third image.

7. The method of claim 1, wherein each of the first plurality of line images captured while at least a portion of the document is illuminated with ultraviolet light, and wherein each of the second plurality of line images captured while at least a portion of the document is illuminated with white light;

and

wherein capturing the first and second images further comprises combining the first and second pluralities of line images to form an interleaved image of the document, and separating the interleaved image into the first image and the second image, the first image being an ultraviolet light illumination image and the second image being a white light illumination image.

8. The method of claim 7, further comprising:

capturing a third plurality of line images of the document, each of the third plurality of line images captured while the document is illuminated with specular reflected white light;

wherein combining the first and second pluralities of line images to form the interleaved image comprises combining the first, second, and third pluralities of line images to form the interleaved image;

wherein separating the interleaved image into the first image and the second image comprises separating the interleaved image into the first image, the second image, and a third image, the third image being a specular reflected white light image; and

wherein comparing the first image to the second image to determine whether tape is adhered to the document comprises comparing the first image, the second image, and the third image to determine whether tape is adhered to the document.

9. The method of claim 7, wherein the first and second pluralities of line images in the interleaved image are arranged in a predetermined sequence.

10. The method of claim 1, wherein comparing the first image to the second image to determine whether tape is adhered to the document comprises:

comparing the first image to the second image to form a transformed image of the document; and

determining whether tape is adhered to the document using the transformed image.

11. The method of claim 10, wherein determining whether tape is adhered to the document using the transformed image comprises determining whether an area of the transformed image having intensity values exceeding a threshold.

12. The method of claim 10, further comprising:

filtering the transformed image to form a filtered transformed image using a smoothing filter, wherein determining whether tape is adhered to the document using the transformed image comprises determining whether the document includes tape based on the filtered transformed image.

13. The method of claim 10, wherein determining whether tape is adhered to the document using the transformed image comprises:

determining a most frequent intensity value of the transformed image;

offsetting the most frequent intensity value to form an offset most frequent intensity value;

associating one or more portions of the transformed image having respective intensity values greater than the offset most frequent intensity value to a predetermined value; and

determining whether an area of the transformed image portions associated with the predetermined value exceeds a predetermined tape area threshold.

14. The method of claim 13, further comprising:

in response to determining that the area of the transformed image portions associated with the predetermined value exceeds the predetermined tape area threshold, outputting a determination that the document includes tape and outputting a tape area.

15. An apparatus for detecting tape on a document, the apparatus comprising:

a first electromagnetic radiation source to emit a first electromagnetic radiation toward a document;

a second electromagnetic radiation source to emit a second electromagnetic radiation toward the document;

an imaging device to capture a first image and a second image of the document, each of the first image and the second image being captured while electromagnetic radiation from at least one of the first electromagnetic radiation source or the second electromagnetic radiation source is emitted toward the document; and

a controller to compare the first image to the second image to determine whether tape is present on the document;

wherein the first image comprises a first plurality of line images of the document, and wherein the second image comprises a second plurality of line images of the document, and

wherein each line image is an image of a vertically spread line of sight of a segment of the document that is less than a whole of the document.

16. The apparatus of claim 15, further comprising:

a third electromagnetic radiation source to emit a third electromagnetic radiation toward the document;

wherein the imaging device further captures a third image of the document, each of the first image, the second image, and the third image being captured while electromagnetic radiation from at least one of the first electromagnetic radiation source, the second electromagnetic radiation source, or the third electromagnetic radiation source is emitted toward the document; and

wherein the controller compares the first image, the second image, and the third image to determine whether tape is present on the document.

17. The apparatus of claim 15 wherein the first electromagnetic radiation source is an ultraviolet light source to emit ultraviolet light toward the document, and wherein the second electromagnetic radiation source is a first white light source to emit white light toward the document.

18. The apparatus of claim 17, wherein the imaging device is a line scan camera, the line scan camera configured to capture a plurality of line images of the document, each of the plurality of line images being captured while light from one of the ultraviolet light source or the first white light source is emitted toward the document;

and

wherein the controller forms an interleaved image using the plurality of line images, the controller further separating the interleaved image into a white light illumination image and an ultraviolet light illumination image, the controller further comparing the white light illumination image to the ultraviolet light illumination image to form a transformed image and determining whether tape is present on the document using the transformed image.

19. The apparatus of claim 18, wherein the first white light source has a first line of sight, and wherein the line scan camera has a second line of sight, the first line of sight forming a first angle with the second line of sight, the apparatus further comprising:

a second white light source to emit white light toward the document, the second white light source having a third line of sight forming a second angle with the second line of sight;

wherein the second angle is greater than the first angle;

wherein each of the plurality of line images is captured while light from one of the ultraviolet light source, the first white light source, or the second white light source is emitted toward the document;

wherein the controller separates the interleaved image into the white light illumination image, the ultraviolet light illumination image, and a specular reflected white light illumination image; and

wherein the controller further compares the white light illumination image, the ultraviolet light illumination image, and the specular reflected white light illumination image to form the transformed image.