Method and algorithm for image processing

• US 6,665,449 B1
• Filed: 09/03/1999
• Issued: 12/16/2003
• Est. Priority Date: 09/03/1999
• Status: Expired due to Term

• Current Assignee: Battelle Memorial Institute
• Original Assignee: Battelle Memorial Institute
• Inventors: He, George G., Moon, Brain D.
• Primary Examiner(s): Mehta, Bhavesh M.
• Assistant Examiner(s): PATEL, KANJIBHAI B
• Application Number:
  US09/389,715
• Time in Patent Office: 1,565 Days
• Field of Search: 382/162, 382/270, 382/274, 382/276, 382/284, 382/108, 382/100, 382/199, 382/266, 382/288, 378/5, 378/4, 378/19, 345/600, 345/440, 345/582, 345/583
• US Class Current: 382/276
• CPC Class Codes: G06T 2207/20061 Hough transform
• CPC Class Codes: G06T 5/50 using two or more images, e.g. averaging or subtraction
• CPC Class Codes: G06V 10/48 by mapping characteristic values of the pattern into a parameter space, e.g. Hough transformation

Abstract

The present invention is a modified Radon transform. It is similar to the traditional Radon transform for the extraction of line parameters and similar to traditional slant stack for the intensity summation of pixels away from a given pixel, for example ray paths that spans 360 degree at a given grid in the time and offset domain. However, the present invention differs from these methods in that the intensity and direction of a composite intensity for each pixel are maintained separately instead of combined after the transformation. An advantage of this approach is elimination of the work required to extract the line parameters in the transformed domain. The advantage of the modified Radon Transform method is amplified when many lines are present in the imagery or when the lines are just short segments which both occur in actual imagery.

Claims

1. A method of image processing, comprising the steps of:

(a) obtaining image data as a plurality of pixels, each of the plurality of pixels having at least two indices, and having an assigned value, wherein said assigned value corresponds to a texture;

(b) for said each pixel, calculating a plurality of summed assigned values, each of said plurality of summed assigned values obtained from a plurality of subsets of pixels away from said each pixel, each of said plurality of summed assigned values having an amplitude and a direction;

(c) calculating and assigning a composite summed assigned value and a composite direction to said each pixel as a plurality of composite assigned values; and

(d) displaying said plurality of composite assigned values as an image;

wherein said texture is obtained by;

for said each pixel, selecting a first set of surrounding pixels and obtaining a first composite intensity from said first set of surrounding pixels;

for said each pixel, selecting a second set of surrounding pixels and obtaining a second composite intensity from said second set of surrounding pixels; and

obtaining said texture which is a ratio of said first and second composite intensities, and assigning said texture to said each pixel.

2. The method as recited in claim 1, wherein said pixels away from said each pixel are those intersecting a ray centered at said each pixel, said ray at discrete angular positions.

3. The method as recited in claim 1, wherein said plurality of summed assigned values is weighted.

4. The method as recited in claim 3, wherein said weighting is a segment sample within a pixel.

5. The method as recited in claim 3, wherein said weighting is a ratio of areas within a pixel on either side of a segment sample.

6. An algorithm for image processing, comprising:

(a) a data input algorithm for receiving image data as a plurality of pixels, each of the plurality of pixels having at least two indices, and having at least one assigned value, wherein said assigned value corresponds to a texture;

(b) a summed assigned value algorithm for calculating a plurality of summed assigned values for each pixel of said plurality of pixels, each of said plurality of summed assigned values obtained from a plurality of subsets of pixels away from said each pixel, each of said plurality of summed assigned values having an amplitude and a direction; and

(c) a composite summed assigned value algorithm for calculating and assigning a composite summed assigned value and a composite direction to said each pixel as a plurality of composite assigned values; and

assigning a composite summed assigned value to said each pixel;

wherein said texture is obtained by;

for said each pixel, selecting a first set of surrounding pixels and obtaining a first composite intensity from said first set of surrounding pixels;

for said each pixel, selecting a second set of surrounding pixels and obtaining a second composite intensity from said second set of surrounding pixels; and

obtaining said texture which is a ratio of said first and second composite intensities, and assigning said texture to said each pixel.

7. The algorithm as recited in claim 6, wherein said pixels away from said each pixel are those intersecting a ray centered at said each pixel, said ray at discrete angular positions.

8. The algorithm as recited in claim 6, wherein said plurality of summed assigned values is weighted.

9. The algorithm as recited in claim 8, wherein said weighting is a segment sample within a pixel.

10. The algorithm as recited in claim 8, wherein said weighting is a ratio of areas within a pixel on either side of a segment sample.