AMENDED CLAIMS

received by the International Bureau on 14 October 2020 (14.10.2020)

C L A I M S

1. 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 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.

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

3. Calibration tool according to claim 1 or 2, wherein for each column at least half of the calibration positions and preferably all calibration positions within the respective column have different heights in the height direction relative to the reference plane.

4. Calibration tool according to any one of the preceding claims, wherein for each column 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. Calibration tool according to claim 4, wherein the sequential reduction in height has a constant decrement relative to the reference plane.

6. Calibration tool according to claim 4, 50

wherein the sequential reduction in height follows a curvature .

7. Calibration tool according to any one of the preceding claims, wherein for each row at least half of the calibration positions and preferably all calibration positions within the respective row have different heights in the height direction relative to the reference plane.

8. Calibration tool according to any one of the preceding claims, wherein for each row the calibration positions within the respective row are sequentially increased in height relative to the reference plane in the circumferential direction.

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

10. Calibration tool according to any one of the preceding claims, 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. Calibration tool according to any one of the preceding claims, wherein for each column the one or more calibration surfaces comprises an individual calibration surface for each calibration position within the respective column .

12. Calibration tool according to claim 11, wherein for each column 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. 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. Calibration tool according to any one of claims 11-13, wherein for each column 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. Calibration tool according to any one of the preceding claims, wherein for each row the one or more calibration surfaces comprises an individual calibration surface for each calibration position within the respective row .

16. Calibration tool according to claim 15, wherein for each row 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. Calibration tool according to any one of the preceding claims, wherein the pattern comprises at least five columns, preferably at least eight columns.

18. Calibration tool according to any one of the preceding claims, wherein the pattern comprises at least four rows, preferably at least five rows.

19. Calibration tool according to any one of the preceding claims, wherein the tool body extends over only a part of a full circumference about the rotation axis .

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

21. Method for calibrating a laser-triangulation measuring system with the use of the calibration tool according to any one of the preceding claims, 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. 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. Method according to claim 22, wherein step e) comprises the step of repeating steps c) and d) for all of the other columns .

24. Method according to any one of claims 21-23, wherein the heights of the calibration positions of each column 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. Method according to any one of claims 21-24, 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 53

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. Method according to claim 25, wherein the method further comprises the steps of:

j) providing a bead-apex on the bead-apex drum; k) measuring the bead-apex using the measuring system; and

1) subtracting the base profile of the empty bead-apex drum as determined in step i) from the measurements .

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