Systems and methods for adjusting lighting of a part based on a plurality of selected regions of an image of the part

• US 6,542,180 B1
• Filed: 01/18/2000
• Issued: 04/01/2003
• Est. Priority Date: 01/07/2000
• Status: Expired due to Term

• Current Assignee: Mitutoyo Corporation
• Original Assignee: Mitutoyo Corporation
• Inventors: Tessadro, Ana M., Wasserman, Richard M.
• Primary Examiner(s): Le, Vu
• Application Number:
  US09/484,897
• Time in Patent Office: 1,169 Days
• Field of Search: 348/86-92, 348/125-134, 382/141-152, 345/327-328, 345/339, 345/343, 345/700, 345/716, 345/719, 345/723, 345/781, 345/803, 345/961
• US Class Current: 348/131
• CPC Class Codes: G01N 21/8806 Specially adapted optical and illumination features
• CPC Class Codes: H04N 23/74 by influencing the scene brightness using illuminating means

Abstract

The lighting behavior of a vision system is inconsistent between vision systems, within a vision system over time or between parts being viewed. This inconsistency makes it difficult to correctly run part programs even within a single run of parts on a single machine. The multi area image quality tool systems, methods and graphical user interfaces adjust the light intensity of a vision system to obtain a desired image quality or characteristic of a captured image. The multi area image quality tool is used to define a plurality of regions of interest within a captured image to be used to determine the image quality or characteristic of the captured image resulting from a current illumination level. The multi area image quality tool allows a user to easily and quickly define multiple regions of interest that can be used to determine the image quality of a captured image. The multi area image quality tool allows the user to specify the location, orientation and size of two or more regions of interest around a critical feature of the captured image, and to specify the light sources to be used to illuminate the part, the image quality to be measured, and a range of acceptable values for that image quality. Portions of the image are extracted based on the defined regions of interest. The image quality of the captured image is determined based on an analysis of the regions of interest and the image quality defined in the multi area image quality tool.

Claims

1. A method of adjusting lighting of a critical region of an object based on an image of the object, the image generated using a vision system including a controllable lighting system and an imaging system, the method comprising:

illuminating the object with the controllable lighting system in a first state;

obtaining an image of the object;

extracting image data of the image corresponding to at least a first region of interest of the image and a second region of interest of the image, the first and second regions of interest located relative to the critical region;

determining at least one image quality of the extracted image data; and

adjusting the state of the controllable lighting system until the at least one image quality of the extracted image data satisfies a selected relationship.

2. The method of claim 1, further comprising repeating the obtaining, extracting, determining and adjusting steps until the image quality of the extracted image data satisfies the selected relationship.

3. The method of claim 1, wherein:

the controllable lighting system comprises a plurality of selectable light sources, each one light source having a controllable light intensity, and

adjusting the state of the controllable lighting system includes at least one of;

selecting at least one of the plurality of selectable light sources, and

adjusting the controllable light intensity of at least one of at least one selected light source.

4. The method of claim 1, wherein:

the controllable lighting system comprises a focusing sub-system; and

adjusting the state of the controllable lighting system comprises adjusting the focusing sub-system.

5. The method of claim 1, further comprising, after adjusting the state of the controllable lighting system so that the at least one image quality of the extracted image data satisfies the selected relationship:

extracting image data from the critical region of the image; and

processing the image data extracted from the critical region.

6. The method of claim 5, wherein:

the critical region includes an edge; and

processing the image data extracted from the critical region comprises analyzing the image data extracted from the critical region to determine a location of the edge.

7. The method of claim 1 wherein the at least one image quality is at least one of contrast and brightness.

8. The method of claim 7, wherein the image quality is the contrast and the selected relationship maximizes a difference in contrast between the image data corresponding to the first and second regions of interest.

9. The method of claim 1, wherein the vision system further comprises a graphical user interface comprising a display portion that displays the obtained image of the object, the method further comprising displaying a graphical user interface widget representing the at least first and second regions of interest superimposed on the obtained image of the object.

10. The method of claim 9, wherein the graphical user interface widget is selectable, the method further comprising:

selecting the graphical user interface widget; and

adjusting at least one of a location of the at least first and second regions of interest and an extent of the at least first and second regions of interest based on an input received from a user of the graphical user interface.

11. The method of claim 1, wherein the vision system further comprises a computerized control system, and at least one step of the method is executed automatically under the instructions of a program that automatically controls the vision system.

12. The method of claim 1, wherein the first and second regions of interest are located in a defined location relative to the critical region.

13. The method of claim 12, wherein the defined location relative to the critical region is one of a location adjacent to the critical region and a location spaced apart from the critical region but located within the image.

14. The method of claim 1, wherein at least one region of interest is located such that at least a majority of that region of interest exhibits substantially uniform image intensity.

15. The method of claim 1, wherein at least one region of interest is located such that at least a majority of that region of interest exhibits a substantially homogeneous pattern corresponding to a portion of the object which exhibits a substantially uniform surface.

16. The method of claim 1, wherein the vision system further comprises a graphical user interface comprising a display portion that displays the obtained image of the object, the method further comprising displaying a graphical user interface widget representing a plurality of sets of boundary lines, each set of boundary lines defining the location and extent of one of the plurality of regions of interest on the image display, wherein each set of boundary lines are independently positionable on the image and display and the extent of each set of boundary lines are independently adjustable on the image display.

17. The method of claim 16, wherein the graphical user interface widget is selectable, the method further comprising:

selecting the graphical user interface widget; and

adjusting at least one of the location of one of the plurality of regions of interest and the extent of one of the plurality of regions of interest based on an input received from a user of the graphical user interface.

18. In a vision system including a controllable lighting system, an imaging system, a processor, and a display device on which image data is displayed;

a graphical user interface widget displayable on the display device and useable to represent a plurality of regions of interest of an image, image data from the at least first and second regions of interest used to control the controllable lighting system, the graphical user interface widget comprising;

a plurality of sets of boundary lines, each set of boundary lines defining the location and extent of one of the plurality of regions of interest on the image display;

each set of boundary lines independently positionable on the image display; and

the extent of each set of boundary lines independently adjustable on the image display.

19. The graphical user interface widget of claim 18, wherein the graphical user interface widget is placed in an initial configuration on the image display based on a point on the image provided to the processor by a user of the vision system.

20. The graphical user interface widget of claim 18, further comprising an indicator of the plurality of regions of interest included in a specific instance of the graphical user interface widget.

21. The graphical user interface widget of claim 20, wherein the indicator is at least one of a line extending between the regions of interest, a set of lines extending between the regions of interest, and a unique color for the boundary lines of the regions of interest included in a specific instance of the graphical user interface widget.