Three-dimensional profilometer
Profilometers for industrial metrology and other applications are described. A line is projected on a surface to be profiled. The line is scanned to build a three dimensional point cloud allowing the three-dimensional (3D) profile of the surface to be determined. In some embodiments, the line is projected by a laser system. In other embodiments, the line is projected by a digital micromirror device (DMD). In still further embodiments, multiple lines, or other patterns are projected.
1. A profilometer, comprising:
a laser light emitter;
a scanner configured to direct a laser beam emitted by the laser light emitter;
a camera aligned with the scanner to detect light reflected by an object;
a processor coupled to the camera and scanner; and
a non-transitory computer-readable medium operatively coupled to the processor and having instructions stored thereon that, when executed by the processor, cause the processor to determine a three dimensional profile of the object using a camera output by:
causing the scanner to project a line onto the object;
determining a position of a leading edge of the reflected laser light by numerically calculating a first derivative of a peak of the reflected light and selecting a maximum value of the first derivative; and
using the determined position of the leading edge to determine the three dimensional profile of the object.
2. The profilometer of claim 1 , wherein the scanner comprises a linear translation stage coupled to the laser light emitter.
3. The profilometer of claim 1 , wherein the scanner comprises a rotating mirror or prism.
4. The profilometer of claim 3 , wherein the rotating mirror or prism is coupled to a galvanometer.
5. The profilometer of claim 1 , wherein the scanner comprises a digital micromirror device.
6. The profilometer of claim 5 , wherein the processor is coupled to the digital micromirror device and configured to cause the digital micromirror device to project a line onto the object.
7. The profilometer of claim 6 , wherein the processor is configured to cause the digital micromirror to selectively project a plurality of patterns onto the object to provide a corresponding plurality of profilometry modes.
8. The profilometer of claim 5 , wherein the processor is coupled to the digital micromirror device and configured to cause the digital micromirror device to project a plurality of lines onto the object.
9. The profilometer of claim 8 , wherein the plurality of lines comprises a cross.
10. The profilometer of claim 8 , wherein the plurality of lines are different colors.
11. The profilometer of claim 1 , further comprising a transmitter coupled to the processor.
12. The profilometer of claim 11 , wherein the transmitter is a wireless transmitter.
13. A method, comprising:
emitting a laser beam;
directing the laser beam onto an object using a scanner;
detecting light reflected from the object to produce a series of two-dimensional images;
determining a position of a leading edge of the reflected laser light by numerically calculating a first derivative of a peak of the reflected light and selecting a maximum value of the first derivative; and
using the images and the determined position to determine a three-dimensional profile of the object.
14. The method of claim 13 , wherein the step of directing the laser beam comprises linearly translating a laser light beam emitter.
15. The method of claim 13 , wherein the step of directing the laser beam comprises changing an angle of the laser beam.
16. The method of claim 15 , wherein the step of changing the angle of the laser beam comprises rotating a mirror or prism.
17. The method of claim 13 , wherein the step of emitting the laser beam comprises projecting a patterned beam using a digital micromirror device.
18. The method of claim 17 , wherein the pattern comprises a line.
19. The method of claim 17 , wherein the pattern comprises a plurality of lines.
20. The method of claim 17 , wherein the pattern is selected from a plurality of patterns corresponding to a plurality of profilometry modes.