Interferometric structured illumination for depth determination

An eyewear device comprising:

• a frame;
• a light source assembly coupled to the frame, the light source assembly comprising a plurality of light sources, wherein (i) each light source of the plurality of light sources is configured to emit light and (ii) the plurality of light sources comprises a respective light source, wherein each light source of the plurality of light sources emits light at a same wavelength and is assigned to groups that can have two potential states:
• an active state where light sources in the group emit light, and
• an inactive state where no light source in the group emits light,
• wherein for a given time period only one group is in an active state, and any remaining groups are in the inactive state;
• a mask coupled to the light source assembly, the mask comprising two adjacent openings that are unobstructed holes in the mask and are configured to pass through light emitted by the light source assembly, wherein the light emitted by the respective light source that is passed through a first opening of the two adjacent openings interferes with the light emitted by the respective light source that is passed through a second opening of the two adjacent openings to form an interference pattern across a target area, the interference pattern having a phase based on a position of the respective light source, and the light from each light source generates a respective interference pattern across the target area;
• a camera assembly coupled to the frame, the camera assembly configured to capture images of a portion of the target area that includes the interference pattern;
• and
• a controller configured to determine depth information for the portion of the target area based on the captured images.

A depth camera assembly (DCA) comprising:

• a light source assembly comprising a plurality of light sources, wherein (i) each light source of the plurality of light sources is configured to emit light and (ii) the plurality of light sources comprises a respective light source, wherein each light source of the plurality of light sources is assigned to groups that can have two potential states:
• an active state where light sources in the group emit light,
• an inactive state where no light source in the group emits light,
• wherein for a given time period only one group is in an active state and any remaining groups are in the inactive state, and
• wherein a first group emits light in a different optical band than light emitted by a second group;
• a mask comprising two adjacent openings that are unobstructed holes in the mask and are configured to pass through light emitted by the light source assembly, wherein the light emitted by the respective light source that is passed through a first opening of the two adjacent openings interferes with the light emitted by the respective light source that is passed through a second opening of the two adjacent openings to form an interference pattern across a target area, the interference pattern having a phase based on a position of the respective light source, and the light from each light source generates a respective interference pattern across the target area;
• a camera assembly configured to capture images of a portion of the target area that includes the interference pattern;
• and
• a controller configured to determine depth information for the portion of the target area based on the captured images.

A depth camera assembly (DCA) comprising:

• a light source assembly comprising a plurality of light sources, wherein (i) each light source of the plurality of light sources is configured to emit light and (ii) the plurality of light sources comprises a respective light source, wherein each light source of the plurality of light sources is assigned to groups that can have two potential states:
• an active state where light sources in the group emit light,
• an inactive state where no light source in the group emits light,
• wherein for a given time period only one group is in an active state and any remaining groups are in the inactive state, and
• wherein a first group emits light that has a different polarization than light emitted by a second group;
• a mask comprising two adjacent openings that are unobstructed holes in the mask and are configured to pass through light emitted by the light source assembly, wherein the light emitted by the respective light source that is passed through a first opening of the two adjacent openings interferes with the light emitted by the respective light source that is passed through a second opening of the two adjacent openings to form an interference pattern across a target area, the interference pattern having a phase based on a position of the respective light source, and the light from each light source generates a respective interference pattern across the target area;
• a camera assembly configured to capture images of a portion of the target area that includes the interference pattern;
• and
• a controller configured to determine depth information for the portion of the target area based on the captured images.