Calibration tool and method

Patent metadata

Field	Value
Publication number	US-12085381-B2
Application number	US-202017599321-A
Country	US
Kind code	B2
Filing date	Mar 13, 2020
Priority date	Apr 5, 2019
Publication date	Sep 10, 2024
Grant date	Sep 10, 2024

Abstract

The invention relates to a calibration tool and a method for calibrating a laser-triangulation measuring system, wherein the calibration tool comprises a tool body that defines a reference plane and that is rotatable relative to the measuring system about a rotation axis perpendicular to said reference plane, wherein the tool body is provided with one or more calibration surfaces that define a pattern of calibration positions, wherein the pattern comprises at least three columns extending in a radial direction away from the rotation axis and at least three rows extending in a circumferential direction about the rotation axis, wherein for each column the calibration positions within said respective column vary in height relative to the reference plane in a height direction perpendicular to said reference plane and wherein for each row the calibration positions within the respective row vary in height in the height direction relative to the reference plane.

First claim

The invention claimed is:

1. A calibration tool for calibrating a laser-triangulation measuring system,
wherein the calibration tool comprises a tool body that is rotatable relative to the measuring system about a rotation axis perpendicular to a reference plane,
wherein the tool body is provided with one or more calibration surfaces that define a pattern of calibration positions,
wherein the pattern comprises at least three columns distributed in a circumferential direction about the rotation axis and each extending in a radial direction away from the rotation axis and at least three rows distributed in the radial direction and each extending in the circumferential direction about the rotation axis,
wherein for each of the at least three columns the calibration positions within said respective column vary in height relative to the reference plane in a height direction perpendicular to said reference plane, and
wherein for each of the at least three rows the calibration positions within the respective row vary in height in the height direction relative to the reference plane.

2. The calibration tool according to claim 1 , wherein the pattern forms a radial grid of calibration positions.

3. The calibration tool according to claim 1 , wherein for each of the at least three columns at least half of the calibration positions within the respective column have different heights in the height direction relative to the reference plane.

4. The calibration tool according to claim 1 , wherein for each of the at least three columns the calibration positions within the respective column are sequentially reduced in height relative to the reference plane in the radial direction away from the rotation axis.

5. The calibration tool according to claim 4 , wherein the sequential reduction in height has a constant decrement relative to the reference plane.

6. The calibration tool according to claim 4 , wherein the sequential reduction in height follows a curvature.

7. The calibration tool according to claim 1 , wherein for each of the at least three rows at least half of the calibration positions within the respective row have different heights in the height direction relative to the reference plane.

8. The calibration tool according to claim 1 , wherein for each of the at least three rows the calibration positions within the respective row are sequentially increased in height relative to the reference plane in the circumferential direction.

9. The calibration tool according to claim 8 , wherein the sequential increase in height has a constant increment relative to the reference plane.

10. The calibration tool according to claim 1 , wherein each calibration position within the pattern has a height in the height direction relative to the reference plane that is different from the heights of the other calibration positions relative to the reference plane in the same column and the same row.

11. The calibration tool according to claim 1 , wherein for each of the at least three columns the one or more calibration surfaces comprises an individual calibration surface for each calibration position within the respective column.

12. The calibration tool according to claim 11 , wherein for each of the at least three columns the tool body is provided with recesses extending between the calibration surfaces within the respective column to space apart said calibration surfaces in the radial direction.

13. The calibration tool according to claim 12 , wherein each calibration surface within the respective column defines a calibration edge at each transition from the respective calibration surface to an adjacent one of the recesses,
wherein at least one of the calibration positions is located at one of said calibration edges.

14. The calibration tool according to claim 11 , wherein for each of the at least three columns the calibration surfaces within the respective column extend in a common plane,
wherein said common plane extends at an oblique angle to the reference plane.

15. The calibration tool according to claim 1 , wherein for each row the one or more calibration surfaces comprises an individual calibration surface for each calibration position within the respective row.

16. The calibration tool according to claim 15 , wherein for each of the at least three rows the calibration surfaces within the respective row are stepped in the height direction from one of the calibration surfaces to the next one of the calibration surfaces in the circumferential direction.

17. The calibration tool according to claim 1 , wherein the pattern comprises at least five columns.

18. The calibration tool according to claim 1 , wherein the pattern comprises at least four rows.

19. The calibration tool according to claim 1 , wherein the tool body extends over only a part of a full circumference about the rotation axis.

20. The calibration tool according to claim 19 , wherein the tool body is formed as a circular segment.

21. A method for calibrating a laser-triangulation measuring system with the use of the calibration tool according to claim 1 ,
wherein the laser-triangulation measuring system comprises a laser and a camera with a field of view,
wherein the method comprises the steps of:
a) providing the calibration tool at least partially within the field of view of the camera;
b) projecting a laser line onto the calibration tool with the laser-triangulation measuring system;
c) rotating the calibration tool about the rotation axis such that the laser line is projected on all calibration positions of a respective one of the columns; and
d) capturing an image of the laser line projected on all calibration positions of the respective column with the camera.

22. The method according to claim 21 , wherein the method further comprises the step of;
e) repeating the steps c) and d) for another one of the columns.

23. The method according to claim 22 , wherein step e) comprises the step of repeating steps c) and d) for all of the other columns.

24. The method according to claim 21 , wherein the heights of the calibration positions of each of the at least three columns relative to the reference plane are predetermined,
wherein the method further comprises the step of calibrating the laser-triangulation measuring system by correlating pixels in each captured image corresponding to the calibration positions of a respective column to the predetermined heights of said calibration positions within said respective column.

25. The method according to claim 21 , wherein the method further comprises the step of:
f) providing an empty bead-apex drum relative to the laser-triangulation measuring system prior to or after steps a) to d), wherein the bead-apex drum has a reference plane and a base profile for supporting a bead-apex relative to the reference plane, wherein the empty bead-apex drum is provided with its reference plane in the same position as the reference plane of the calibration tool;
g) projecting a laser line onto the empty bead-apex drum with the laser-triangulation measuring system;
h) capturing an image of the laser line projected on the empty bead-apex drum; and
i) determining the base profile of the empty bead-apex drum relative to the reference plane of the empty bead-apex drum.

26. The method according to claim 25 , wherein the method further comprises the steps of:
j) providing a bead-apex on the bead-apex drum;
k) me

Assignees

• Vmi Holland Bv

Inventors

• Kellij Egbert Grietinus
• Van De Vrugt John
• Tielenburg Niels
• Verbruggen Teunis Johannes
• Beekman Peter
• Van Voskuilen Cees Johan
• Nusselder Robin
• Berghorst Gerjan Asuerus
• Verlaan Titus Ruben
• Kofoed Bart
• Bergmans Quinten Matthijs

Classifications

• G01C25/00

  Manufacturing, calibrating, cleaning, or repairing instruments or devices referred to in the other groups of this subclass (testing, calibrating or compensating compasses G01C17/38) · CPC title

• G01S7/497

  Means for monitoring or calibrating · CPC title

• G01C11/30

  by triangulation · CPC title

• B29D2030/482

  Applying fillers or apexes to bead cores · CPC title

• B29D2030/3207

  Positioning the beads · CPC title