Performing a comparison between two images which are scaled to a common resolution

• US 9,111,183 B2
• Filed: 01/04/2013
• Issued: 08/18/2015
• Est. Priority Date: 01/04/2013
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Moon, Rodney G., Rector, Gerald C., Ridgway, Philip
• Primary Examiner(s): Patel, Nirav G
• Application Number:
  US13/734,202
• Publication Number:
  US 20140193063A1
• Time in Patent Office: 956 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G06F 18/22 Matching criteria, e.g. proximity measures
• CPC Class Codes: G06T 3/00 Geometric image transformations in the plane of the image
• CPC Class Codes: G06T 3/40 Scaling of whole images or parts thereof, e.g. expanding or contracting
• CPC Class Codes: G06V 10/10 Image acquisition document image scanning and transmission H04N1/00; control of digital cameras H04N23/60
• CPC Class Codes: G06V 10/751 Comparing pixel values or logical combinations thereof, or feature values having positional relevance, e.g. template matching

Abstract

A system and method for comparing digital images, such as checks images used by banks, includes receiving and processing the images to be compared, including scaling the images to a common resolution, as well as filtering them to remove spot noise, background pels, and other non-information carrying elements. One or more regions of each image are selected for comparison. The selected regions are compared to one another by subtracting the pels of one image from the other'"'"'s pels. A determination is made of whether the two or more images are duplicates of one another, or depict a substantially identical subject, based on the results of the subtractions. Furthermore, the amount of filtering and scaling may be adjusted to enhance the effects of the system to take advantage of common characteristics that may be known or detected in a particular set of images to be compared.

Claims

1. A system for comparing images, comprising:

a computer having a processor, and a computer-readable storage device;

a program embodied on the storage device for execution by the processor, the program having a plurality of program modules, including;

a receiving module configured to receive a first image and a second image;

a processing module configured to process the first image and the second image, wherein the processing includes scaling the first image and the second image to a common resolution;

a selecting module configured to select one or more pel regions of the scaled first image and of the scaled second image;

a subtracting module configured to subtract the one or more selected pel regions of the scaled first image from the one or more selected pel regions of the scaled second image, respectively; and

a determining module configured to determine whether the first image and the second image depict identical subjects based on results of the subtracting module,

wherein the processing module is further configured to filter at least one of the first image and the second image, and

wherein one or both of the first image and the second image are bitonal, having black pels and white pels, and the processing module is further configured to filter the first image and the second image by removing black pels or groups of black pels surrounded by white pels, and the black pels or groups of black pels exist in a square grid having the size 1 by 1 pels to 4 by 4 pels, preferably having the size 3 by 3 to 4 by 4 pels.

2. The system of claim 1, wherein the processing module is further configured to make the amount of filtering of the first image and of the second image adjustable.

3. The system of claim 1, wherein the scaling module is further configured to make the amount of scaling of the first image and of the second image adjustable.

4. The system of claim 1, wherein the processing module is configured to scale the first image and the second image to a common resolution between 75 and 90 pels per inch.

5. The system of claim 1, wherein the first image and the second image are of negotiable instruments, including check images.

6. A computer program product for comparing images, the computer program product comprising a computer readable non-transitory storage medium having program code embodied therewith, the program code readable/executable by a processor to perform a method, comprising:

receiving a first image and a second image, by the processor;

processing the first image and the second image, by the processor, wherein the processing includes scaling the first image and the second image to a common resolution;

selecting one or more pel regions of the scaled first image and of the scaled second image, by the processor;

subtracting the one or more selected pel regions of the scaled first image from the one or more selected pel regions of the scaled second image, respectively, by the processor; and

determining whether the first image and the second image depict identical subjects, by the processor, based on results of the subtraction,

wherein the processing of the first image and of the second image, by the processor, further comprises filtering at least one of the first image and the second image, and

wherein one or both of the first image and the second image, received by the processor, are bitonal, having black pels and white pels, and the filtering, by the processor, further comprises removing black pels or groups of black pels surrounded by white pels, and the black pels or groups of black pels exist in a square grid having the size 1 by 1 pels to 4 by 4 pels, preferably having the size 3 by 3 to 4 by 4 pels.

7. The computer program product of claim 6, wherein the filtering of one or both of the first image and the second image, by the processor, is recursive.

8. The computer program product of claim 6, wherein the filtering of one or both of the first image and the second image, by the processor, is adjustable.

9. The computer program product of claim 6, wherein the scaling of one or both of the first image and the second image, by the processor, is adjustable.

10. The computer program product of claim 6, wherein the scaling of the first image and of the second image, by the processor, is set to a common resolution between 91 and 100 pels per inch.

11. The computer program product of claim 6, wherein the scaling of the first image and of the second image, by the processor, is set to a common resolution between 75 and 90 pels per inch.

12. The computer program product of claim 6, wherein the first image and the second image, received by the processor, are of negotiable instruments, including check images.