Calibration validation using geometric features in galvanometric scanning systems

Patent metadata

Field	Value
Publication number	US-11525968-B2
Application number	US-202016817357-A
Country	US
Kind code	B2
Filing date	Mar 12, 2020
Priority date	Mar 14, 2019
Publication date	Dec 13, 2022
Grant date	Dec 13, 2022

Abstract

Some embodiments may include a method of generating assessment data in a system including a galvanometric scanning system (GSS) having a laser device to generate a laser beam and an X-Y scan head module to position the laser beam on a work piece. The method may include selecting a dimension based on a desired accuracy for validation (and/or a characteristic of an imaging system in embodiments that utilize an imaging system). The method may include commanding the GSS to draw a mark based on a polygon or ellipse of the selected dimension around a predetermined target point associated with the work piece to generate assessment data, and following operation of the GSS based on said commanding, validating a calibration of the GSS using the assessment data (or an image thereof in embodiments that utilize an imaging system). Other embodiments may be disclosed and/or claimed.

First claim

The invention claimed is:

1. An imaging system for use with a galvanometric scanning system (GSS) having a laser device to generate a laser beam and an X-Y scan head to position the laser beam on a workpiece, the imaging system comprising:
one or more processors configured to:
recognize a geometric marking feature in an image of the workpiece, wherein the geometric marking feature is centered on a point;
generate a geometric feature having a center, wherein the geometric feature is based on a logical polygon or ellipse;
locate the point by comparing the recognized geometric marking feature to the generated geometric feature, wherein the point is located without distinguishing a line intersection in the image of the workpiece; and
determine an offset between the located point and a predetermined target point, wherein the offset is indicative of an accuracy of a calibration of the GSS.

2. The imaging system of claim 1 , wherein the geometric marking feature comprises a pattern including plural polygon portions or plural ellipse portions centered on the point, and wherein recognize a geometric marking feature in an image of the workpiece further comprises search the image for the largest one of the plural polygon portions or plural ellipse portions visible to the imaging system at a lowest magnification setting.

3. The imaging system of claim 1 , wherein the offset comprises a first offset and in a case that the first offset is not greater than the threshold, the first offset is indicative of the accuracy of the calibration of the GSS, and wherein the one or more processors are further configured to:
recognize an additional geometric marking feature in an image of the workpiece or another workpiece, wherein the additional geometric marking feature is centered on a point;
generate an additional geometric feature having a center, in a case that the first offset is greater than the threshold, wherein the generated additional geometric feature is based on a larger logical polygon or ellipse;
locate the point associated with the recognized additional geometric feature by comparing the recognized additional geometric marking feature to the generated additional geometric feature;
determine a second offset between the point associated with the recognized additional geometric feature and the predetermined target point, wherein the second offset is indicative of the accuracy of the calibration of the GSS.

4. A system, comprising:
a galvanometric scanning system (GSS) having a laser device to generate a laser beam and an X-Y scan head to position the laser beam on a workpiece; and
an imaging system including one or more processors configured to:
recognize a geometric marking feature in an image of the workpiece, wherein the geometric marking feature is centered on a point;
generate a geometric feature having a center, wherein the geometric feature is based on a logical polygon or ellipse;
locate the point by comparing the recognized geometric marking feature to the generated geometric feature, wherein the point is located without distinguishing a line intersection in the image of the workpiece; and
determine an offset between the located point and a predetermined target point, wherein the offset is indicative of an accuracy of a calibration of the GSS.

5. The system of claim 4 , wherein the geometric marking feature comprises a pattern including plural polygon portions or plural ellipse portions, and wherein recognize a geometric marking feature in an image of the workpiece further comprises search the image for the largest one of the plural polygon portions or plural ellipse portions visible to the imaging system at a lowest magnification setting.

6. The system of claim 4 , wherein the offset comprises a first offset and in a case that the first offset is not greater than the threshold, the first offset is indicative of the accuracy of the calibration of the GSS, and wherein the one or more processors are further configured to:
recognize an additional geometric marking feature in an image of the workpiece or another workpiece, in a case that the first offset is greater than the threshold, wherein the additional geometric marking feature is centered on a point;
generate an additional geometric feature having a center, wherein the generated additional geometric feature is based on a larger logical polygon or ellipse;
locate the point associated with the recognized additional geometric marking feature by comparing the recognized additional geometric marking feature to the generated additional geometric feature;
determine a second offset between the point associated with the recognized additional geometric marking feature and the predetermined target point, wherein the second offset is indicative of the accuracy of the calibration of the GSS.

7. The system of claim 4 , wherein the imaging system comprises an integrated optical coordinate measurement machine (CMM), wherein the integrated optical CMM comprises a component of the GSS.

8. A method of validation of a calibration of a galvanometric scanning system (GSS) having a laser device to generate a laser beam and an X-Y scan head to position the laser beam on a workpiece, the method comprising:
selecting a dimension based on a desired accuracy for validation and one or more characteristics of an imaging system to image the workpiece;
commanding the GSS to draw a mark based on a polygon or ellipse of the selected dimension around a predetermined target point associated with the workpiece to generate assessment data; and
following operation of the GSS based on said commanding:
imaging the workpiece using the imaging system to generate an image;
recognizing a geometric marking feature in the image, wherein the geometric marking feature is centered on a point;
generating a geometric feature having a center, wherein the geometric feature is based on a logical polygon or ellipse;
locating the point by comparing the recognized geometric marking feature to the generated geometric feature, wherein the point is located without distinguishing a line intersection in the image of the workpiece; and
determining an offset between the located point and the predetermined target point, wherein the offset is indicative of an accuracy of the calibration of the GSS.

9. The method of claim 8 , wherein a characteristic of the one or more characteristics comprises a field of view of the imaging system at a lowest magnification.

10. The method of claim 8 , wherein commanding the GSS to draw a mark based on a polygon or ellipse of the selected dimension around a predetermined target point associated with the workpiece comprises remotely commanding the GSS based on one or more communications transmitted over a network.

11. The method of claim 8 , wherein the imaging system comprises an integrated optical coordinate measurement machine (CMM), wherein the integrated optical CMM comprises a component of the GSS.

12. The method of claim 8 , wherein the polygon has n-order symmetry in which n is greater than one.

13. The method of claim 12 , wherein the polygon comprises a rectangle, an equilateral triangle, a hexagon, an octagon, or an icosagon.

Assignees

• Nlight Inc

Inventors

• Small Jay
• Gross Ken

Classifications

• G02B26/101

  with both horizontal and vertical deflecting means, e.g. raster or XY scanners (colour television using laser beams scanning a display screen H04N9/3129) · CPC title

• G02B6/4224 Primary

  using visual alignment markings, e.g. index methods · CPC title

• G02B26/105 Primary

  with one or more pivoting mirrors or galvano-mirrors (G02B26/101 takes precedence) · CPC title