METHOD FOR ASSESSING A DEPRESSION, IN PARTICULAR A BORE, IN A WORKPIECE

Abstract

A method for assessing a wall of a depression, particularly a bore, in a workpiece. The method requires that a light beam in the depression is deflected so that at least two regions of the at least one wall portion are illuminated, and in that, by means of the at least two regions, reflected light is guided along the first axis out of the depression and is used outside the depression for determining the geometry and/or reflectivity of the at least one wall portion. The determination of the geometry or reflectivity is carried out interferometrically and/or wherein in each region for at least 250 pixels, at least one distance value and/or at least one intensity and/or reflectivity value is detected, and/or wherein the regions and/or the at least one light beam each has an area of at least 0.1 mm.sup.2.

Claims

1. A method for examining or measuring at least one wall portion of a depression introduced into a workpiece by means of an optical measurement method, wherein at least one light beam is introduced along a first axis into the depression and wherein the geometry or reflectivity of the at least one wall portion is measured by means of the at least one light beam, wherein the at least one light beam is deflected in the depression in such a way that at least two regions of the at least one wall portion are illuminated and that in each case reflected light is guided along the first axis out of the depression through the at least two regions and is used outside the depression for determining the geometry or reflectivity of the at least one wall portion, wherein the determination of the geometry or reflectivity is carried out interferometrically or in that at least one distance value or at least one intensity value or reflectivity value is detected in each region of the at least two regions for at least 25 pixels; or wherein the at least two regions or the at least one light beam each have an area of at least 0.1 mm.sup.2; and wherein the measurement is carried out for a plurality of regions.

2. The method according to claim 1, wherein the at least two regions each have an area in the range of at least 2 mm.sup.2 or up to a maximum of 50 mm.sup.2.

3. The method according to claim 1, wherein the determination of the geometry or reflectivity is carried out simultaneously and wherein the respective simultaneously illuminated areas each intersect a common plane perpendicular to the first axis.

4. The method according to claim 1, wherein the at least one wall portion is a size in the range of at least 25 mm.sup.2 or maximum 100 cm.sup.2.

5. The method according to claim 1, wherein the depression has a size or diameter in the range from 4 mm to 25 mm or the depression or the at least one wall section has a depth in the range of at least 2 mm or at most 1 m.

6. The method according to claim 1, carried out such that, per region, at least 1000 pixels or at most 50,000 pixels are detected, the pixels having a 2- or 3-dimensional arrangement or being uniformly distributed over the region or the region's projection onto a plane in which the first axis is located, or at least five pixels are recorded in the direction of the first axis or the recorded pixels span at least 0.5 m per area in the direction of the first axis.

7. The method according to claim 1, wherein a material type, roughness, or color derived from the reflectivity or at least one material type or color difference or at least one boundary is detected based on different reflectivity values.

8. The method according to claim 1, wherein, in particular, all regions of the plurality of regions adjacent to one another overlap and wherein reflectance images of the overlapping regions are set together to form a continuous reflectivity mapping or the geometries of the overlapping regions are set together to form a cohesive geometry.

9. The method according to claim 1, wherein the at least two regions in a plane perpendicular to the first axis are arranged such that at least one connecting line from a first to a second one of the at least two regions passes through the first axis.

10. The method according to claim 1, wherein a beam splitter is moved along the first axis or rotates about the first axis and thereby different regions of the at least two regions in the depression are illuminated by the at least one light beam.

11. The method according to claim 1, wherein a centering of the first axis in the depression is effected based on the specific geometry of the at least one wall section.

12. A device for examining or measuring at least one wall portion of a depression introduced into a workpiece by means of an optical measurement method, wherein the device introduces at least one light beam into the depression through a lance, and wherein the device measures by means of the at least one light beam the geometry or reflectivity of the at least one wall portion, wherein the device is designed such that for each circumferential region in the direction of a longitudinal extension of the lance at least five adjacent pixels are detected or the pixels detected in the direction of the longitudinal extension of the lance correspond to at least 0.1 m on the circumferential region of the lance, wherein the device rotates the lance about the longitudinal extension of the lance or moves the lance along the longitudinal extension of the lance; wherein the lance has at least one beam splitter which is arranged and configured to deflect the at least one light beam in such a way that the at least one light beam exits from the lance in a plurality of adjacent planes perpendicular to the longitudinal extension of the lance, and that the device is configured to guide light which has emerged and reflected back at the at least two regions through the lance and out of the lance, and to use the light outside the lance for determining the geometry or reflectivity of the at least one wall portion, wherein the device is configured to detect at least one distance value or at least one intensity or reflectivity value via each of at least two peripheral regions for at least 25 pixels, or wherein the at least two peripheral regions each span at least 0.1 mm, or have at least an extent of five pixels or at least 0.5 m and wherein the device is configured to determine the geometry or reflectivity interferometrically.

13. A use of a beam splitter for examining or measuring at least one wall section of a depression introduced into a workpiece by means of an optical measurement method, wherein the beam splitter is configured to divide an incident light beam into at least two beams which have at least 1 mm.sup.2 of cross-sectional area.

14. The use according to claim 13, wherein the beam splitter is arranged on a hollow measuring lance and the lance is rotated about its longitudinal axis or the lance is moved along its longitudinal axis.

15. The use according to claim 14, wherein the examination or measurement of the at least one wall section is carried out by examining or measuring a plurality of overlapping regions of the at least one wall section, which each are completely illuminated by the light beam at a time or wherein surfaces of the wall section covered by at least two regions are illuminated, examined or measured at least twice in succession, and a data set of the examination or measurement of the at least one wall section is generated.

Description

[0063] Possible embodiments of the method according to the invention will be explained in the following purely by way of example with reference to the following purely schematic figures. In the drawings:

[0064] FIG. 1 shows a cross section through a lance in a bore

[0065] FIG. 2 shows the image of the geometry of two diametrically opposed regions and

[0066] FIG. 3 shows a representation of the geometry of a bore obtained from a plurality of overlapping regions with a depression.

[0067] FIG. 1 shows a cross section through a lance in a bore with a depression. The lance is designed as a round tube closed at the end with two diametrically opposed outlet openings. In the region of the outlet openings, a glass body which is triangular in cross section is arranged on the base of the lance and is coated in a reflective manner on its surfaces shaped like a gabled roof. It forms a beam splitter. A light beam falling through the lance, which is divided and deflected by the beam splitter, is also indicated by dashed lines. In order to illustrate this division also in the light beam falling from above through the lance, two dashed lines were also provided here. The deflected light beam parts each illuminate a region of the wall. If the lance is now rotated slightly after the area has been received, and a new receptacle is produced, it is possible to achieve an image extending over the entire circumference of the bore through corresponding repetitions of the process, which can be obtained by correspondingly overlapping regions. In addition, the lance can then also be pushed further into the hole or pulled out of the latter, and a further, preferably overlapping segment can be obtained by a plurality of receptacles as tell as temporary rotation.

[0068] FIG. 2 shows the illustration of two simultaneously imaged regions of the bore of FIG. 1. Their arrangement does not correspond to the arrangement in the bore. However, this can be reconstructed. They are shown, so to speak, split open next to each other.

[0069] A corresponding reconstruction based on a plurality of overlapping regions is shown in FIG. 3. In this case, the bore was shown from the outside, as it were, going out from the workpiece, and from above. The acquired point cloud was shown for illustration. The boundary layer between the workpiece and the bore is shown, so to speak. Partially spiral depressions can be seen in the wall of the bore, which can arise, for example, through a bore with a rotating and advancing drill.