3D SCANNER USING MERGED PARTIAL IMAGES

Abstract

A structured light 3D scanner based on the principle of triangulation with a light source for generating a light pattern, two cameras with two-dimensional sensors recording the reflection of the light pattern from a target object, and one axis moving the cameras. Wherein the cameras are arranged with at least partly overlapping fields of view and where the sensors in the cameras are read out partially and concurrently during at least some period of the scanning process, thus providing partial images and where the partial images are merged prior to performing the triangulation calculations.

Claims

1-12. (canceled)

13. A structured light 3D scanner based on the principle of triangulation comprising a light source for generating a light pattern at least two cameras with two-dimensional sensors recording the reflection of the light pattern from a target object one axis moving the cameras, and where the cameras are arranged with at least partly overlapping fields of view, where the at least two cameras are mounted on one side of the light source and at least two cameras are mounted on the other side of the light source.

14. The scanner according to claim 13, where the light pattern contains at most five non-intersecting lines.

15. The scanner according to claim 13, where the cameras and the light source are mounted in a fixed spatial configuration on a scan head, such that the axis moving the cameras also moves the light source.

16. The scanner according to claim 13, where the at least two cameras on one side of the light source are arranged to have substantially the same viewing angle.

17. The scanner according to claim 13, where the at least two cameras on one side of the light source are arranged to have substantially different viewing angles.

18. The scanner according to claim 13, where the setup of the at least two cameras on one side of the light source is mirrored around the light source.

19. The scanner according to claim 13, where the at least two cameras on one side of the light source are arranged on a single printed circuit board with a flexible section.

20. The scanner according to claim 13, where the scanner is configured for scanning dental objects.

21. The scanner according to claim 13, where the scanner is configured for scanning dental impressions.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0065] The above and/or additional objects, features and advantages of the present invention, will be further elucidated by the following illustrative and non-limiting detailed description of embodiments of the present invention, with reference to the appended drawings, wherein:

[0066] FIG. 1 shows a schematic of particular embodiment of the scanner according to the invention, and

[0067] FIG. 2 shows a 3D rendered version of a first embodiment of the invention, and

[0068] FIG. 3 shows a 3D rendered version of a second embodiment of the invention.

DETAILED DESCRIPTION

[0069] FIG. 1 shows a schematic of particular embodiment of the scanner according to the invention, as seen from above. A laser line generator 10 is the light source. It generates a fan of light—appearing as a single ray 16 from above—such that the light pattern is a line perpendicular to the plane of the figure. Two cameras 11 are mounted fixed to each other on one side of the light source. Together they can travel on a linear sweeping axis 15. The circular area 20 within the dashed line indicates the scan volume. The two cameras' fields of view are indicated by the intersection of area 20 and the two triangular areas 21, one for each camera 11. Finally, the overlapping field of view is indicated by the gray area 22. As indicated by the arrow 30, a target object contained in the scan volume can be rotated by a rotary axis (oriented perpendicularly to the plane of the figure and thus not shown). Note that in the sense of this invention, the field of view does not extend to infinity nor includes very small distances from the camera, because sufficiently sharp images can only be captured within a limited range of distances. This limitation is also reflected in the definition of scan volume.

[0070] FIG. 2 shows a 3D rendered version of an embodiment with one pair of cameras 11 on one side and another pair of cameras 12 on the other side of a line laser light source 10. The light pattern is a line when projected on the target object (not shown), or a fan 16 in 3D. All cameras 11 and 12 and the light source 10 are mounted fixed to each other on a holder 13, which again is mounted on a sled 14 traveling on a linear sweeping axis 15. For EMC compliance, the PCB's on which the cameras are mounted are enclosed in metal cages 17. The sled 14, the holder 13, and all elements thereon, i.e., 11, 12, 10, 17, and the interconnecting un-numbered elements, constitute the scan head.

[0071] In the embodiment of FIG. 2, the two cameras on either side have substantially different viewing angles. FIG. 3 shows an embodiment that is identical to the one of FIG. 2, except that the two cameras 11 on the one side of the light source have substantially equal viewing angles, and so do the two cameras 12 on the other side of the light source.

REFERENCES

[0072] Sonka, M, Hlavac V, and Boyle R: Image processing, analysis, and machine vision, second ed., 1998, ISBN 0-534, 95393-X. [0073] Hartley, R, and Zisserman A: Multiple View Geometry in computer vision, 2003, Cambridge University Press, ISBN 0-521-54051-8.