Visual inspection device and process

• US 5,260,780 A
• Filed: 11/15/1991
• Issued: 11/09/1993
• Est. Priority Date: 11/15/1991
• Status: Expired due to Fees

• Current Assignee: Centrax International Corporation
• Original Assignee: Threadmasters, Inc.
• Inventors: Staudt, John J. III
• Primary Examiner(s): Britton, Howard W.
• Application Number:
  US07/792,813
• Time in Patent Office: 725 Days
• Field of Search: 358/101, 358/107
• US Class Current: 348/139
• CPC Class Codes: G01B 11/002 for measuring two or more coordinates
• CPC Class Codes: G01B 11/024 by means of diode-array scanning
• CPC Class Codes: G01B 11/2433 for measuring outlines by shadow casting
• CPC Class Codes: G01B 2210/52 Combining or merging partially overlapping images to an overall image
• CPC Class Codes: H04N 7/18 Closed-circuit television [CCTV] systems, i.e. systems in which the video signal is not broadcast

Abstract

A vision inspection system capable of high resolution of distanced portions of the same part is provided, allowing for dimensional calculations to be made on large parts with high resolution. A process for inspection of a part is provided, comprising the steps of: mapping a first portion of the part; mapping a second portion of the part; defining a first reference coordinate corresponding to a first reference point located on the first portion of the part; defining a second reference coordinate corresponding to a second reference point located on the second portion of the part; determining the number of coordinates between the first reference coordinate and the second reference coordinate; calculating a constant corresponding to a third portion of the part, wherein the third portion of the part is not mapped; and adding the constant to the number of coordinates between the first and the second reference coordinates.

Claims

1. A process for inspection of a part comprising the steps of:

mapping a first portion of the part;

mapping a second portion of the part;

defining a first reference coordinate corresponding to a first reference point located on the first portion of the part;

defining a second reference coordinate corresponding to a second reference point located on the second portion of the part;

determining the number of coordinates between the first reference coordinate and the second reference coordinate;

calculating a constant corresponding to a third portion of the part, wherein the third portion of the part is not mapped; and

adding the constant to the number of coordinates between the first and the second reference coordinates.

2. A process as in claim 1 further comprising:

capturing the image of the first portion with a first camera;

capturing the image of the second portion with a second camera; and

displaying the image of the first portion and the image of the second portion in different portions of a display.

3. A process as in claim 1 wherein said calculating comprises:

determining the distance between the focal plane of the first camera and the focal plane of the second camera to provide a camera distance value, and

scaling the camera distance value to a camera distance coordinate value wherein the camera distance coordinate value equals the constant.

4. A process as in claim 1 further comprising:

backlighting the part with a light source;

wherein said mapping of the first portion comprises;

capturing the image of the first portion with a first camera;

defining a first field of view which partially comprises

a first image of the first portion of the part and

light emitted from the light source;

wherein the first portion blocks at least part of the light, creating different light intensities in differing areas of the first field of view;

dividing the first field view into a first set of coordinates;

assigning a coordinate intensity value to each of the first set of coordinates, wherein the coordinate intensity value of each coordinate corresponds to the light intensity at each coordinate within the first field of view; and

displaying the light intensity value of each coordinate of the first set within a first portion of a display;

wherein said mapping of the second portion comprises;

capturing the image of the second portion with a second camera;

defining a second field of view which partially comprises

a second image of the first portion of the part and

light emitted from the light source,

wherein the second portion blocks at least part of the light, creating different light intensities in differing areas of the second field of view;

dividing the second field view into a second set of coordinates;

assigning a coordinate intensity value to each of the second set of coordinates, wherein the coordinate intensity value of each coordinate corresponds to the light intensity at each coordinate within the second field of view; and

displaying the light intensity value of each coordinate of the second set within a second portion of the display; and

wherein said calculating comprises;

determining the distance between the focal plane of the first camera and the focal plane of the second camera to provide a camera distance value and

scaling the camera distance value to a camera distance coordinate value wherein the camera distance coordinate value equals the constant.

5. A process as in claim 1 further comprising backlighting the part with a light source.

6. A process as in claim 5 further wherein said mapping of the first portion comprises:

defining a field of view, which partially comprises

a first image of the first portion of the part,

light emitted from the light source, and

wherein the first portion blocks at least part of the light, creating different light intensities in differing areas of the field of view;

dividing the field view into a number of coordinates; and

assigning a coordinate intensity value to each of the coordinates, wherein the coordinate intensity value of each coordinate corresponds to the light intensity at each coordinate within the field of view.

7. A process as in claim 6 further comprising displaying the light intensity value of each coordinate on a display.

8. A system for inspection of a part comprising:

means for mapping a first portion of the part;

means for mapping a second portion of the part;

means for defining a first reference coordinate corresponding to a first reference point located on the first portion of the part;

means for defining a second reference coordinate corresponding to a second reference point located on the second portion of the part;

means for determining the number of coordinates between the first reference coordinate and the second reference coordinate;

means for calculating a constant corresponding to third portion of the part, wherein the third portion of the part is not mapped; and

means for adding the constant to the number of coordinates between the first and the second reference coordinates.

9. A system as in claim 8 further comprising:

means for capturing the image of the first portion with a first camera;

means for capturing the image of the second portion with a second camera; and

means for displaying the image of the first portion and the image of the second portion in different portions of a display.

10. A system as in claim 8 wherein said means for calculating comprises:

means for determining the distance between the focal plane of the first camera and the focal plane of the second camera to provide a camera distance value and

means for scaling the camera distance value to a camera distance coordinate value wherein the camera distance coordinate value equals the constant.

11. A system as in claim 8 further comprising:

means for backlighting the part with a light source; and

wherein said means for mapping of the first portion comprises;

means for capturing the image of the first portion with a first camera;

means for defining a first field of view which partially comprises;

a first image of the first portion of the part and

light emitted from the light source,

wherein the first portion blocks at least part of the light, creating different light intensities in differing areas the first field of view;

means for dividing the first field view into a first set of coordinates;

means for assigning a coordinate intensity value to each of the first set of coordinates, wherein the coordinate intensity value of each coordinate corresponds to the light intensity at each coordinate within the first field of view; and

means for displaying the light intensity value of each coordinate of the first set within a first portion of a display;

wherein said means for mapping of the second portion comprises;

means for capturing the image of the second portion with a second camera;

means for defining a second field of view which partially comprises

a second image of the second portion of the part and

light emitted from the light source,

wherein the second portion blocks at least part of the light, creating different light intensities in differing areas of the second field of view;

means for dividing the second field view into a second set of coordinates;

means for assigning a coordinate intensity value to each of the second set of coordinates, wherein the coordinate intensity value of each coordinate corresponds to the light intensity at each coordinate within the second field of view; and

means for displaying the light intensity value of each coordinate of the second set within a second portion of the display; and

wherein said means for calculating comprises;

means for determining the distance between the focal plane of the first camera and the focal plane of the second camera to provide a camera distance value and

means for scaling the camera distance value to a camera distance coordinate value wherein the camera distance coordinate value equals the constant.

12. A system as in claim 8 further comprising means for backlighting the part with a light source.

13. A process as in claim 12 further wherein said means for mapping of the first portion comprises:

means for defining a field of view which partially comprises;

a first image of the first portion of the part and

light emitted from the light source,

wherein the first portion blocks at least part of the light, creating different light intensities in differing areas of the field of view;

means for dividing the field view into a number of coordinates;

means for assigning a coordinate intensity value to each of the coordinates, wherein the coordinate intensity value of each coordinate corresponds to the light intensity at each coordinate within the field of view.

14. A system as in claim 13 further comprising means for displaying the light intensity value of each coordinate on a display.

15. A system for inspection of a part comprising:

a computer;

a first camera connected to the computer and having a first field of view;

a second camera connected to the computer and having a second field of view; and

a light source located such that the part is between said first camera and said light source;

wherein the first field of view includes a first portion of the part;

wherein the second field of view includes a second portion of the part;

wherein the computer digitizes the first field of view to define a first digitized field of view;

wherein the computer digitizes the second field of view to define a second digitized field of view;

wherein the computer assigns a set of coordinate address values, one to each coordinate of each of the digitized fields of view;

wherein the computer assigns a set of coordinate image values to each coordinate of each of the digitized fields of view;

wherein the computer pastes the first and the second digitized fields of view together as if the first and second digitized fields of view were separate halves of the one total field of view, whereby a pasted digitized field of view is defined;

wherein the distance in coordinates between any coordinate of the first digitized field of view and the second digitized field of view is corrected by a correction factor; and

wherein the correction factor is determined from the distance between the first camera and the second camera.