Structured light projection module, depth camera, and method for manufacturing structured light projection module
A structured light projection module, a depth camera, and a method for manufacturing the structured light projection module are provided. The module comprises: a light source, comprising a plurality of sub-light sources that are arranged in a two-dimensional array and configured to emit two-dimensional patterned beams corresponding to the two-dimensional array, and the two-dimensional patterned beams comprising two-dimensional patterns; a lens, receiving and converging the two-dimensional patterned beams; and a diffractive optical element, receiving the two-dimensional patterned beams converged and emitted from the lens, and projecting speckle patterned beams corresponding to speckle patterns. The speckle patterns comprise a plurality of image patterns corresponding to the two-dimensional patterns, and the image patterns are rotated by an angle such that edges of the image patterns are not in parallel with a baseline between the structured light projection module and a capture module.
1. A structured light projection module, comprising:
a light source, comprising a plurality of sub-light sources arranged in a two-dimensional array and configured to emit two-dimensional patterned beams corresponding to the two-dimensional array, and the two-dimensional patterned beams comprising two-dimensional patterns;
a lens, receiving and converging the two-dimensional patterned beams; and
a diffractive optical element, receiving the two-dimensional patterned beams converged and emitted from the lens, and projecting speckle patterned beams corresponding to speckle patterns, wherein
the speckle patterns comprise a plurality of image patterns corresponding to the two-dimensional patterns, and the image patterns are rotated by an angle such that edges of the image patterns are not in parallel with a baseline between the structured light projection module and a capture module, wherein relationships between adjacent image patterns of the plurality of image patterns comprise a spacing relationship and at least one of an overlapping relationship or an adjoining relationship, and the spacing relationship refers to that an average interval between the adjacent image patterns is greater than or equal to an average interval between speckles in the plurality of image patterns.
2. The structured light projection module according to claim 1 , wherein the angle is 2-10 degrees.
3. The structured light projection module according to claim 1 , wherein the light source is a vertical-cavity surface-emitting laser (VCSEL) array light source.
4. The structured light projection module according to claim 1 , wherein the two-dimensional patterns include irregularly distributed speckles.
5. The structured light projection module according to claim 1 , wherein the plurality of image patterns and the two-dimensional patterns are in a central symmetry relationship.
6. The structured light projection module according to claim 1 , wherein the speckle patterns are composed of the plurality of image patterns corresponding to the two-dimensional patterns, wherein the plurality of image patterns is in an irregular arrangement.
7. A depth camera, comprising:
a structured light projection module comprising:
a light source, comprising a plurality of sub-light sources that arranged in a two-dimensional array and configured to emit two-dimensional patterned beams corresponding to the two-dimensional array, and the two-dimensional patterned beams comprising two-dimensional patterns;
a lens, receiving and converging the two-dimensional patterned beams; and
a diffractive optical element, receiving the two-dimensional patterned beams converged and emitted from the lens, and projecting speckle patterned beams corresponding to speckle patterns to an object, wherein the speckle patterns comprise a plurality of image patterns corresponding to the two-dimensional patterns, and the image patterns are rotated by an angle such that edges of the image patterns are not in parallel with a baseline between the structured light projection module and a capture module, wherein relationships between adjacent image patterns of the plurality of image patterns comprise a spacing relationship and at least one of an overlapping relationship or an adjoining relationship, and the spacing relationship refers to that an average interval between speckles in the plurality of image patterns;
the capture module, used for capturing the speckle patterns projected onto the object; and
a processor, receiving the collected speckle patterns and performing a depth calculation to obtain a depth image of the object.
8. The depth camera according to claim 7 , wherein a size of a matching window selected in the speckle patterns is not less than a gap between adjacent image patterns in the depth calculation.
9. A method for manufacturing a structured light projection module, comprising:
providing a substrate, wherein a material of the substrate comprises copper or ceramic;
arranging a light source on the substrate, wherein the light source comprises a plurality of sub-light sources that are arranged in a two-dimensional array and configured to emit two-dimensional patterned beams corresponding to the two-dimensional array, and the two-dimensional patterned beams comprising two-dimensional patterns;
arranging a lens on the substrate, for receiving and converging the two-dimensional patterned beams; and
arranging a diffractive optical element on the substrate, for receiving the two-dimensional patterned beams converged and emitted from the lens, and projecting speckle patterned beams corresponding to speckle patterns, wherein
the speckle patterns comprise a plurality of image patterns corresponding to the two-dimensional patterns, and the image patterns are rotated by an angle such that edges of the image patterns are not in parallel with a baseline between the structured light projection module and a capture module, wherein relationships between adjacent image patterns of the plurality of image patterns comprise a spacing relationship and at least one of an overlapping relationship or an adjoining relationship and the spacing relationship refers to that an average interval between the
adjacent image patterns is greater than or equal to an average interval between speckles in the plurality of image patterns.
10. The method according to claim 9 , wherein the angle is 2-10 degrees.
11. The method according to claim 9 , wherein the light source is a vertical-cavity surface-emitting laser (VCSEL) array light source.
12. The method according to claim 9 , wherein the two-dimensional patterns include irregularly distributed speckles.
13. The method according to claim 9 , wherein the plurality of image patterns and the two-dimensional patterns are in a central symmetry relationship.
14. The method according to claim 9 , wherein the speckle patterns are composed of the plurality of image patterns corresponding to the two-dimensional patterns, wherein the plurality of image patterns is in an irregular arrangement.