Illumination modules that emit structured light
A depth camera includes an illumination module and an image detector module. The illumination module outputs structured light that illuminates a capture area. The image detector module captures an image of the structured light as reflected from object(s) within the capture area. The illumination module includes a VCSEL array and optical element(s), such as projection optics, an MLA or DOE, or combinations thereof. Projection optics receive a light pattern emitted by the VCSEL array and project the light pattern. An optical element, downstream from the projection optics, can cause a total number of features included in the structured light to be greater than the number of features included in the light pattern projected by the projection optics. In an embodiment, a pitch of an MLA is offset relative to a pitch of the VCSEL array. Various structures can include alignment elements to aid manufacture of the illumination module.
1. A depth camera system, comprising:
an illumination module configured to output structured light that illuminates a capture area; and
an image detector module configured to capture an image of the structured light as reflected from one or more objects within the capture area;
the illumination module including
a VCSEL array comprising a plurality of vertical cavity surface emitting lasers (VCSELs), wherein each of the VCSELs is configured to emit a separate beam of light, and wherein the plurality of VCSELs are configured to collectively emit a light pattern; and
projection optics configured to receive the light pattern emitted by the VCSELs of the VCSEL array and project the light pattern;
wherein the structured light output by the illumination module is created at least in part based on the light pattern projected by the projection optics;
wherein the projection optics include
a field lens that is positioned adjacent the VCSEL array and configured to receive the beams of light emitted by the VCSELs of the VCSEL array and converge the beams to a single pupil; and
an objective lens that is positioned adjacent the field lens at the single pupil and configured to receive the converged beams from the field lens and diverge the beams to produce the light pattern projected by the projection optics.
2. The depth camera system of claim 1 , wherein:
the light pattern projected by the projection optics include a number of features; and
the illumination module also includes an optical element that is positioned optically downstream from the projection optics and configured to cause a total number of features included in the structured light output by the illumination module to be greater than the number of features included in the light pattern projected by the projection optics.
3. The depth camera system of claim 2 , wherein the optical element, that is positioned optically downstream from the projection optics, comprises a beam splitter that is configured to cause the total number of features included in the structured light output by the illumination module to be twice the number of features included in the light pattern projected by the projection optics.
4. The depth camera system of claim 2 , wherein the optical element, that is positioned optically downstream from the projection optics, comprises a diffractive optical element (DOE) that is configured to cause the total number of features included in the structured light output by the illumination module to be an integer multiple of the number of features included in the light pattern projected by the projection optics.
5. The depth camera system of claim 4 , wherein the diffractive optical element (DOE) is configured to cause the total number of features included in the structured light output by the illumination module to be twice or thrice the number of features included in the light pattern projected by the projection optics.
6. The depth camera system of claim 1 , further comprising:
one or more processors configured to produce a depth image in dependence on the image captured by the image detector module.
7. The depth camera system of claim 6 , wherein the one or more processors is/are also configured to update an application based on the depth image.
8. The depth camera system of claim 1 , wherein the VCSEL array comprises an X-by-Y two dimensional array of VCSELs on a single semiconductor substrate.
9. A method, comprising:
emitting a separate beam of light from each of a plurality of vertical cavity surface emitting laser (VCSELs) of a VCSEL array to thereby collectively emit a light pattern;
receiving the beams of light emitted by the VCSELs of the VCSEL array, at a field lens that is adjacent the VCSEL array, and using the field lens to converge the beams to a single pupil;
receiving the converged beams from the field lens, at an objective lens that is positioned adjacent the field lens at the single pupil, and using the objective lens to diverge the beams to produce a projected light pattern;
illuminating a capture area with structured light that is created at least in part based on the projected light pattern produced using the objective lens; and
capturing an image of the structured light as reflected from one or more objects within the capture area.
10. The method of claim 9 , wherein:
the projected light pattern, produced using the objective lens, includes a number of features; and
further comprising using an optical element, which is positioned optically downstream from the field lens and the objective lens, to cause a total number of features included in the structured light to be greater than the number of features included in the projected light pattern produced using the objective lens.
11. The method of claim 10 , wherein the optical element that is optically downstream from the field lens and the objective lens comprises a beam splitter, and the using the optical element comprises using the beam splitter to cause the total number of features included in the structured light to be twice the number of features included in the projected light pattern produced using the objective lens.
12. The method of claim 10 , wherein the optical element that is optically downstream from the field lens and the objective lens comprises a diffractive optical element (DOE), and the using the optical element comprising using the DOE to cause the total number of features included in the structured light to be an integer multiple of the number of features included in the projected light pattern produced using the objective lens.
13. The method of claim 12 , wherein the using the DOE causes the total number of features included in the structured light to be twice or thrice the number of features included in the light pattern projected using the projection optics.
14. The method of claim 9 , further comprising producing a depth image in dependence on the captured image.
15. The method of claim 14 , further comprising updating an application based on the depth image.
16. The method of claim 9 , wherein the VCSEL array comprises an X-by-Y two dimensional array of VCSELs on a single semiconductor substrate.