Methods and apparatus for machine vision inspection using single and multiple templates or patterns

• US 6,748,104 B1
• Filed: 03/24/2000
• Issued: 06/08/2004
• Est. Priority Date: 03/24/2000
• Status: Expired due to Term

• Current Assignee: Cognex Corporation
• Original Assignee: Cognex Corporation
• Inventors: Wallack, Aaron, Bachelder, Ivan
• Primary Examiner(s): Dastouri, Mehrdad
• Assistant Examiner(s): KIBLER, VIRGINIA M
• Application Number:
  US09/535,633
• Time in Patent Office: 1,537 Days
• Field of Search: 382/151, 382/147, 382/149, 382/145, 382/209, 382/181, 348/129, 348/130, 348/95
• US Class Current: 382/151
• CPC Class Codes: G06T 2207/30141 Printed circuit board [PCB]
• CPC Class Codes: G06T 2207/30148 Semiconductor; IC; Wafer
• CPC Class Codes: G06T 7/001 using an image reference approach
• CPC Class Codes: G06T 7/74 involving reference images or patches

Abstract

A method for rapid determination of the position and/or orientation of a semiconductor device, electronic component or other object includes performing multiple times an operation of matching a pattern against an image. The matching operation finds the location, if any, of a respective pattern in the image and determines the degree of match. The position and orientation of the object is determined from the results of one of the matching operations, for example, from the operation that revealed the highest degree of match.

Claims

1. A machine vision method for determining any of a location and an orientation in an image of an electronic component handled by a suction nozzle or other part-handling apparatus, the method comprising the steps of:

A. performing plural times a step of matching a pattern with the same image, each time matching a different pattern, each pattern modeling one or more respective portions of the electronic component,

B. each matching step including the steps of (i) finding a location, if any, of the respective pattern in the image, (ii) determining a degree of match between the respective pattern and the image, (iii) determining any of a position and an orientation of the electronic component based on results of the matching step, wherein the patterns are selected so as to match, individually or in combination, at least a majority of expected imaged portions of the electronic component under expected conditions of execution of the method,

C. the performing step including (i) inspecting the image to determine a condition of the electronic component as a result of any of a defect in the component and an error in handling of the component by the suction nozzle or other part-handling apparatus, and (ii) rejecting a determination of any of a position and an orientation of the electronic component based on its condition,

D. the inspecting step including determining a condition of the electronic component as a result of handling by the suction nozzle or other part-handling apparatus by, any of (i) finding in the image a shape corresponding to a part-handling apparatus, and (ii) finding in the image a shape corresponding to a suction nozzle.

2. The method of claim 1, wherein

a first pattern models at first side region of the electronic component, and

a second pattern models a second side region of the electronic component, and

a third pattern models the first side region of the electronic component and the second side region of the electronic component.

3. The method of claim 1, wherein the patterns are selected so that at least one of them is likely to be found in the image under expected conditions of execution of the method.

4. The method of claim 3, wherein the patterns are selected so that at least one of them is likely to be found in the image with an acceptable degree of match under expected conditions of execution of the method.

5. The method of claim 1, wherein each pattern models one or more respective side regions of the component, each side region comprising a respective side edge of the component and any of

(i) a portion each of one or more side edges adjacent each respective side edge, and

(ii) one or more corners that define a transition to one or more such adjacent sides edges.

6. The method of claim 5, wherein

a first pattern models a first side region of the component, and

a second pattern models any of

(i) a second side region of the component, and

(ii) the first side region of the component and a second side region of the component.

7. The method of claim 5, wherein

a first pattern models a first side region of the component, and

a second pattern models a second side region of the component, and

a third pattern models the first side region of the component and the second side region of the component.

8. The method of claim 1, wherein the step of determining any of a position and an orientation is based on one or more factors including (i) a characteristic of the pattern, and (ii) a degree of match between a pattern and the image.

9. The method of claim 8, wherein

a first pattern models a first side region of the component,

a second pattern models a second side region of the component,

a third pattern models the first side region of the component and the second side region of the component,

the step of determining any of a position and an orientation is based on one or more factors including (i) a characteristic of the pattern, namely, whether it models a single side region or whether it models multiple side regions, and (ii) a degree of match between a pattern and the image.

10. The method of claim 1, wherein the step of rejecting a determination of any of a position and an orientation of the electronic component includes the steps of

rejecting a determination of any of position and orientation of the electronic component based on a found location of a first pattern in the image, and

determining any of position and orientation of the electronic component based on a found location of a second pattern in the image.

11. The method of claim 1, including the steps of

manipulating the electronic component with a suction nozzle or other part-handling apparatus, and

wherein the inspecting step includes determining a part-handling condition of the electronic component.