Structure-guided automatic alignment for image processing

• US 6,829,382 B2
• Filed: 06/13/2001
• Issued: 12/07/2004
• Est. Priority Date: 06/13/2001
• Status: Active Grant

• Current Assignee: Leica Microsystems Gmbh (Danaher Corporation)
• Original Assignee: Shih-Jong J. Lee
• Inventors: Oh, Seho, Lee, Shih-Jong J.
• Primary Examiner(s): Mehta, Bhavesh M.
• Assistant Examiner(s): STREGE, JOHN B
• Application Number:
  US09/882,734
• Publication Number:
  US 20030026473A1
• Time in Patent Office: 1,273 Days
• Field of Search: 382/151, 382/152, 382/294, 382/287, 382/291, 382/190, 382/199, 382/201
• US Class Current: 382/151
• CPC Class Codes: G06T 2207/30164 Workpiece; Machine component
• CPC Class Codes: G06T 7/0002 Inspection of images, e.g. flaw detection
• CPC Class Codes: G06T 7/12 Edge-based segmentation
• CPC Class Codes: G06T 7/33 using feature-based methods

Abstract

When application domain structure information is erroneously encoded into parameters for image processing and measurements the accuracy of the result can degrade. A structure-guided automatic alignment system for image processing receives an image input and application domain structure input and automatically creates an estimated structure output having improved alignment. Measurement and image processing robustness are improved.

Claims

1. A structure estimation module comprising:

a. means to receive an image input;

b. means to receive an application domain structure input;

c. a preprocessing module that receives the image input having a pre-processed image output;

d. a distributed estimation module that receives the pre-processed image and application domain structure inputs having an estimated structure output wherein the distributed estimation module comprises

i. a sub-region generation module having a sub-region output;

ii. a robust structure-guided estimation module that receives the sub-region output and a box caliper input having a feature parameter output wherein the box caliper robust structure-guided estimation module comprises;

(a) means to perform row-wise robust feature direction estimation and weight adjustment having an adjusted weight output;

(b) means to perform column-wise robust feature direction estimation and weight adjustment having an adjusted weight output;

(c) means to perform overall robust feature direction estimation and weight adjustment having a feature direction estimation result.

2. A structure estimation module comprising:

a. means to receive an image input;

b. means to receive an application domain structure input;

c. a preprocessing module that receives the image input having a pre-processed image output;

d. a distributed estimation module that receives the pre-processed image and application domain structure inputs having an estimated structure output wherein the distributed estimation module comprises

i. a sub-region generation module having a sub-region output;

ii. a robust structure-guided estimation that receives the sub-region output and a circle caliper input having a feature parameter output wherein the circle caliper robust structure-guided estimation module comprises;

(a) means to perform radial-wise robust center estimation and weight adjustment having adjusted weight output;

(b) means to perform angular-wise robust center estimation and weight adjustment having adjusted weight output;

(c) means to perform overall robust center estimation and weight adjustment having center estimation output.

3. A structure estimation module comprising:

a. means to receive an image input;

b. means to receive an application domain structure input;

c. a preprocessing module that receives the image input having a pre-processed image output;

d. a distributed estimation module that receives the pre-processed image and application domain structure inputs having an estimated structure output wherein the distributed estimation module comprises

i. a sub-region generation module having a sub-region output;

ii. a robust structure-guided estimation module that receives the sub-region output and an arc caliper input having a feature parameter output wherein the arc caliper robust structure-guided estimation module comprises;

(a) means to perform radial-wise robust center estimation and weight adjustment having adjusted weight output;

(b) means to perform angular-wise robust center estimation and weight adjustment having adjusted weight output;

(c) means to perform overall robust center estimation and weight adjustment having center estimation output.

4. A robust feature direction estimation and weight adjustment method for a group of box caliper sub-regions comprises:

(a) for each sub-region, estimate the feature direction using line estimation without constraints;

(b) for a group of sub-regions, estimate the feature direction using line estimation constrained by a parallelism relation;

(c) compare the sub-region feature direction estimated in step (a), with the group direction estimated in step (b) and adjust weight for the sub-region based on an error function;

(d) update and output the group of sub-regions box caliper estimate of the feature direction.

7. The method of claim 4 further comprising a step for re-alignment of the box caliper direction vector responsive to the group of sub-regions estimate of the feature direction output.

5. A robust feature direction estimation and weight adjustment method for a group of circle caliper sub-regions comprises:

(a) for each sub-region, estimate the center of a circular arc without constraints;

(b) for a group of sub-regions, estimate the center of circular arcs constrained by the same center point;

(c) compare the sub-region center estimated in step (a), with the group center estimated in step (b) and adjust the weight for the sub-region base on an error function;

(d) update and output the group of sub-regions center.

8. The method of claim 5 further comprising a step for re-alignment of the circle caliper center location responsive to the output of the group of sub-regions estimate of the center of circular arcs output.

6. A robust feature direction estimation and weight adjustment method for a group of arc caliper sub-regions comprises the following step:

(a) for each sub-region, estimate the center of a circular arc without constraints;

(b) for a group of sub-regions, estimate the center of circular arcs constrained by the same center point;

(c) compare the sub-region center estimated in step (a), with the group center estimated in step (b) and adjust weight for the sub-region based on an error function;

(d) update and output the group of sub-regions estimate for the center circular arcs.

9. The method of claim 6 further comprising a step for re-alignment of the arc caliper center location responsive to the output of the group of sub-regions estimate of the center of circular arcs output.