Depth sensing techniques for virtual, augmented, and mixed reality systems
A system and method for operating a depth sensor. A configuration operation can be performed by storing a first sequence of operation steps which define a first depth sensing mode of operation, and a second sequence of operation steps which define a second depth sensing mode of operation, in the memory. In response to a first request for depth measurements according to the first depth sensing mode of operation, the depth sensor can be operated in the first mode of operation by causing it to execute the first sequence of operation steps. In response to a second request for depth measurements according to the second depth sensing mode of operation, and without performing an additional configuration operation, the depth sensor can be operated in the second mode of operation by causing it to execute the second sequence of operation steps.
1. A depth sensor comprising:
memory storing information usable to operate the depth sensor, the information including:
a first sequence of operation steps which define a first depth sensing mode of operation of the depth sensor, the first sequence of operation steps including one or more common operation steps, and
a second sequence of operation steps which, in combination with the one or more common operation steps, define a second depth sensing mode of operation of the depth sensor; and
a processor communicatively coupled to the memory, the processor configured to:
receive a first request for first depth measurements according to the first depth sensing mode of operation and, in response to the first request, operate the depth sensor in the first mode of operation by executing the first sequence of operation steps to generate the first depth measurements; and
receive a second request for second depth measurements according to the second depth sensing mode of operation and, in response to the second request and without storing additional operation steps in the memory, operate the depth sensor in the second mode of operation by executing the second sequence of operation steps and the one or more common operation steps to generate the second depth measurements.
2. The depth sensor of claim 1 , wherein the depth sensor is a time-of-flight camera.
3. The depth sensor of claim 1 , wherein the first depth sensing mode of operation corresponds to a first distance range of measurements and the second depth sensing mode of operation corresponds to a second distance range of measurements which is different from the first distance range of measurements.
4. The depth sensor of claim 1 , wherein the first depth measurements and the second depth measurements are usable in a virtual, augmented, or mixed reality display system.
5. The depth sensor of claim 1 , wherein the first depth sensing mode of operation corresponds to a first frame rate and the second depth sensing mode of operation corresponds to a second frame rate which is different than the first frame rate.
6. The depth sensor of claim 1 , wherein the first depth sensing mode of operation corresponds to a first frame rate and the second depth sensing mode of operation corresponds to a second frame rate which is slower than the first frame rate.
7. The depth sensor of claim 1 , wherein at least one of the second sequence of operation steps comprises a delay.
8. The depth sensor of claim 1 , wherein the processor is further configured to receive at least one configuration request and, in response to the at least one configuration request, store, in the memory, the first sequence of operation steps and the second sequence of operations steps.
9. The depth sensor of claim 1 , wherein the first depth sensing mode of operation or the second depth sensing mode of operation is a short-range and high frame rate mode of operation.
10. The depth sensor of claim 9 , wherein the short-range and high frame rate mode of operation is used for sensing depths at ranges less than about 2 m with frame rates greater than about 20 Hz.
11. The depth sensor of claim 1 , wherein the first depth sensing mode of operation or the second depth sensing mode of operation is a short-range and low frame rate mode of operation.
12. The depth sensor of claim 11 , wherein the short-range and low frame rate mode of operation is used for sensing depths at ranges less than about 2 m with frame rates less than about 20 Hz.
13. The depth sensor of claim 1 , wherein the first depth sensing mode of operation or the second depth sensing mode of operation is a long-range and high frame rate mode of operation.
14. The depth sensor of claim 13 , wherein the long-range and high frame rate mode of operation is used for sensing depths at ranges from about 2-4 m with frame rates greater than about 20 Hz.
15. The depth sensor of claim 1 , wherein the first depth sensing mode of operation or the second depth sensing mode of operation is a long-range and low frame rate mode of operation.
16. The depth sensor of claim 15 , wherein the long-range and low frame rate mode of operation is used for sensing depths at ranges from about 2-4 m with frame rates less than about 20 Hz.
17. The depth sensor of claim 1 , wherein:
the first depth sensing mode of operation is a short-range and high frame rate mode of operation;
the second depth sensing mode of operation is a short-range and low frame rate mode of operation;
the one or more common operation steps include steps to: i) capture a short-range intensity sub-frame using a short exposure, and ii) capture four phase sub-frames;
the first sequence of operation steps includes a first delay; and
the second sequence of operation steps includes a second delay that is longer than the first delay.
18. The depth sensor of claim 1 , wherein:
the first depth sensing mode of operation is a long-range and high frame rate mode of operation;
the second depth sensing mode of operation is a long-range and low frame rate mode of operation;
the one or more common operation steps include steps to: i) capture a long-range intensity sub-frame using a long exposure, ii) capture four phase sub-frames for a first illumination modulation frequency, and iii) capture four phase sub-frames for a second illumination modulation frequency;
the first sequence of operation steps includes a first delay; and
the second sequence of operation steps includes a second delay that is longer than the first delay.