Method and system for identifying an image feature and method and system for determining an optimal color space for use therein

• US 6,226,399 B1
• Filed: 05/27/1999
• Issued: 05/01/2001
• Est. Priority Date: 05/27/1999
• Status: Expired due to Fees

• Current Assignee: Microscan Systems Inc (Omron Corporation)
• Original Assignee: Integral Vision, Inc.
• Inventors: Robinson, David A
• Primary Examiner(s): Tran, Phuoc
• Application Number:
  US09/321,284
• Time in Patent Office: 705 Days
• Field of Search: 382/162, 382/165, 382/167, 382/190, 382/191, 382/224, 382/225
• US Class Current: 382/162
• CPC Class Codes: G01J 3/462 Computing operations in or between colour spaces; Colour management systems
• CPC Class Codes: G01J 3/50 using electric radiation detectors
• CPC Class Codes: G06T 2207/10024 Color image
• CPC Class Codes: G06T 7/11 Region-based segmentation
• CPC Class Codes: G06V 10/143 Sensing or illuminating at different wavelengths

Abstract

A method and system are provided for identifying an image feature of an object. The system preferably includes a machine vision system for capturing an original color image of the object in a first color space defined by a first set of color axes to obtain a first set of image data. The first set of image data is transformed within the machine vision system to a second set of image data in an optimal color space having an optimal set of color axes which define an optimal direction wherein the amount of inter axis correlation of the second set of image data is minimized. The machine vision system then manipulates the second set of image data to identify the image feature. Color differences existing in the original color image are amplified and separation between chromatically different regions of the original color image are maximized in the optimal color space. Preferably, the optimal set of color axes are three orthogonal axes. The first set of image data is rotated to match the optimal direction. In this way, the first set of image data is reorganized along the optimal set of color axes. The machine vision system can also be utilized to capture a color image of an ideal object in the first color space to obtain an ideal set of image data and to compute the optimal set of color axes from the ideal set of image data wherein the optimal set of color axes is object specific.

Claims

1. A method for identifying an image feature of an object in a machine vision system, the method comprising the steps of:

capturing an original color image of the object in a first color space defined by a first set of color axes to obtain a first set of image data;

transforming the first set of image data to a second set of image data in an optimal color space having an optimal set of color axes which define an optimal direction wherein the amount of inter axis correlation of the second set of image data is minimized; and

manipulating the second set of image data to identify the image feature wherein color differences existing in the original color image are amplified and separation between chromatically different regions of the original color image are maximized in t he optimal color space.

2. The method as claimed in claim 1 where in the optimal set of color axes are three orthogonal axes.

3. The method as claimed in claim 1 wherein the step of transforming the first set of image data includes the step of chromatically rotating the first set of image data to match the optimal direction.

4. The method as claimed in claim 1 wherein the step of transforming the first set of image data includes the step of reorganizing the first set of image data along the optimal set of color axes.

5. The method as claimed in claim 1 further comprising the steps of:

capturing a color image of an ideal object in the first color space to obtain an ideal set of image data; and

computing the optimal set of color axes from the ideal set of image data wherein the optimal set of color axes is object specific.

6. A system for identifying an image feature of an object, the system comprising:

means for capturing an original color image of the object in a first color space defined by a first set of color axes to obtain a first set of image data;

means for transforming the first set of image data to a second set of image data in an optimal color space having an optimal set of color axes which define an optimal direction wherein the amount of inter axis correlation of the second set of image data is minimized; and

means for manipulating the second set of image data to identify the image feature wherein color differences existing in the original color image are amplified and separation between chromatically different regions of the original color image are maximized in the optimal color space.

7. The system as claimed in claim 6 wherein the optimal set of color axes are three orthogonal axes.

8. The system as claimed in claim 6 wherein the means for transforming the first set of image data includes means for chromatically rotating the first set of image data to match the optimal direction.

9. The system as claimed in claim 6 wherein the means for transforming the first set of image data includes means for reorganizing the first set of image data along the optimal set of color axes.

10. The system as claimed in claim 6 further comprising:

means for capturing a color image of an ideal object in the first color space to obtain an ideal set of image data; and

means for computing the optimal set of color axes from the ideal set of image data wherein the optimal set of color axes is object specific.