Compact, low cost VCSEL projector for high performance stereodepth camera
A VCSEL projector and method for using the same are disclosed. In one embodiment, the apparatus comprises a vertical cavity surface emitting laser (VCSEL) array comprising a plurality of VCSELs; a micro-lens array coupled to the VCSEL array and having a plurality of lenses, and each of the plurality of lenses is positioned over a VCSEL in the VCSEL array; and a projection lens coupled to the micro-lens array (MLA), where light emitted by the VCSEL array is projected as a sequence of patterns onto an object by the projection lens.
1. An apparatus comprising:
a vertical cavity surface emitting laser (VCSEL) array including a plurality of VCSELs;
a micro-lens array coupled to the VCSEL array and having a plurality of lenses, and each of the plurality of lenses is positioned over a VCSEL in the VCSEL array, wherein a centerline of a lens of the plurality of lenses is positioned at an offset with respect to a centerline of a corresponding VCSEL and the lens is directly coupled to the corresponding VCSEL; and
a projection lens coupled to the micro-lens array (MLA), wherein light emitted by the VCSEL array is projected as a sequence of patterns onto an object by the projection lens.
2. The apparatus defined in claim 1 , wherein the plurality of lenses of the MLA cause light emitted by VCSELs in the VCSEL array to bend so that more light emitted from the VCSELs travels through the projection lens.
3. The apparatus defined in claim 2 , wherein the plurality of lenses of the MLA that are farther from a center of the VCSEL array are operable to bend the light more than those closer to the center of the VCSEL array.
4. The apparatus defined in claim 3 , wherein the plurality of lenses of the MLA bend light emitted by the VCSELs in an increasing amount as a lens of the plurality of lenses is closer to an edge of a field of view.
5. The apparatus defined in claim 2 , wherein the center of each lens of the plurality of lenses and a corresponding VCSEL are misaligned to cause emitted light from the corresponding VCSEL to be bent.
6. The apparatus defined in claim 5 , wherein a lens and a corresponding VCSEL with more misalignment bends light more than a lens and corresponding VCSEL with less misalignment.
7. The apparatus defined in claim 1 , wherein the light includes infra-red (IR) light and the projection lens includes an IR projection lens.
8. An apparatus comprising:
a projector configured to project a sequence of light patterns on an object, wherein the projector includes:
a vertical cavity surface emitting laser (VCSEL) array including a plurality of VCSELs;
a micro-lens array coupled to the VCSEL array and having a plurality of lenses, and each of the plurality of lenses is positioned over a VCSEL in the VCSEL array, wherein a centerline of a lens of the plurality of lenses is at an offset with respect to a centerline of a corresponding VCSEL;
a projection lens coupled to the micro-lens array (MLA), wherein light emitted by the VCSEL array is projected as the sequence of light patterns onto the object by the projection lens, wherein the offset between the centerline of the lens and the centerline of the corresponding VCSEL is dependent on a location of the projection lens with respect to the VCSEL array;
a first camera configured to capture a sequence of images of the object illuminated with the projected light patterns; and
a processing unit to receive the sequence of images and reconstruct depth information using triangulation.
9. The apparatus defined in claim 8 , wherein the plurality of lenses of the MLA cause light emitted by VCSELs in the VCSEL array to bend so that more light emitted from the VCSELs travels through the projection lens.
10. The apparatus defined in claim 9 , wherein the plurality of lenses of the MLA that are farther from a center of the VCSEL array are operable to bend the light more than those closer to the center of the VCSEL array.
11. The apparatus defined in claim 10 , wherein the plurality of lenses of the MLA bend light emitted by the VCSELs in an increasing amount as a lens of the plurality of lenses is closer to an edge of a field of view.
12. The apparatus defined in claim 9 , wherein the center of each lens of the plurality of lenses and a corresponding VCSEL are misaligned to cause emitted light from the corresponding VCSEL to be bent.
13. The apparatus defined in claim 12 , wherein a lens and a corresponding VCSEL with more misalignment bends light more than a lens and corresponding VCSEL with less misalignment.
14. The apparatus defined in claim 8 , wherein the projector includes an infra-red (IR) projector and the projection lens includes an IR projection lens.
15. The apparatus defined in claim 8 , inlcuding a second camera configured to capture a second image of the object illuminated with the projected light patterns and configured to capture a texture image of the object in the second image.
16. The apparatus defined in claim 15 , wherein the projector includes an infrared (IR) projector, the first camera includes an IR camera, and the second camera includes a red, green, and blue (RGB) camera.
17. A method comprising:
projecting a sequence of light patterns on an object using a projector, wherein the projector includes:
a vertical cavity surface emitting laser (VCSEL) array including a plurality of VCSELs;
a micro-lens array coupled to the VCSEL array and having a plurality of lenses, and each of the plurality of lenses is positioned over a VCSEL in the VCSEL array, wherein a centerline of a lens of the plurality of lenses is at an offset with respect to a centerline of a corresponding VCSEL and the lens is directly coupled to the corresponding VCSEL;
a projection lens coupled to the micro-lens array (MLA), wherein light emitted by the VCSEL array is projected as the sequence of light patterns onto the object by the projection lens, wherein the offset between the centerline of the lens and the centerline of the corresponding VCSEL is dependent on a location of the projection lens with respect to the VCSEL array;
capturing, using a camera, a sequence of images of the sequence of light patterns; and
generating depth information via triangulation using the sequence of images.
18. The method defined in claim 17 , including bending light emitted by VCSELs in the VCSEL array using the plurality of lenses of the MLA so that more light emitted from the VCSELs travels through the projection lens.
19. The method defined in claim 18 , wherein the plurality of lenses of the MLA that are farther from a center of the VCSEL array are operable to bend the light more than those closer to the center of the VCSEL array.
20. The method defined in claim 19 , wherein the plurality of lenses of the MLA bend light emitted by the VCSELs in an increasing amount as a lens of the plurality of lenses is closer to an edge of a field of view.
21. The method defined in claim 18 , wherein the center of each lens of the plurality of lenses and a corresponding VCSEL are misaligned to cause emitted light from the corresponding VCSEL to be bent.
22. The method defined in claim 21 , wherein a lens and a corresponding VCSEL with more misalignment bends light more than a lens and corresponding VCSEL with less misalignment.
23. The method defined in claim 17 , wherein the light includes infra-red (IR) light and the projection lens includes an IR projection lens.
24. An article of manufacture having one or more non-transitory computer readable storage media comprising instructions which, when executed by a system, cause the system to perform operations including:
receiving a sequence of images of a sequence of light patterns captured by a camera, wherein the light patterns are projected by a projector that includes:
a vertical cavity surface emitting laser (VCSEL) array including a plurality of VCSELs;
a micro-lens array coupled to the VCSEL array and having a plurality of lenses, and each of the plurality of lenses is positioned over a VCSEL in the VCSEL array, wherein a centerline of a lens of the plurality of lenses is at an offset with respect to a centerline of a corresponding VCSEL and the lens is directly coupled to the corresponding VCSEL;
a projection lens coupled to the micro-lens array (MLA), wherein light emitted by the VCSEL array is projected as a sequence of patterns onto an object by the projection lens, wherein the offset between the centerline of the lens and the centerline of the corresponding VCSEL is dependent on a location of the projection lens with respect to the VCSEL array; and
generating depth information via triangulation using the sequence of images.
25. The article of manufacture defined in claim 24 , wherein the method further includes bending light emitted by VCSELs in the VCSEL array using the plurality of lenses of the MLA so that more light emitted from the VCSELs travels through the projection lens.
26. The article of manufacture defined in claim 25 , wherein the plurality of lenses of the MLA that are farther from a center of the VCSEL array are operable to bend the light more than those closer to the center of the VCSEL array.