Interference handling in time-of-flight depth sensing

1. A method for operating a camera, the method comprising:

generating a first set of pixel values, the first set of pixel values representative of light received from a scene by a light sensor including light originating from the camera, background light, and light originating from other camera light sources;

generating a second set of pixel values, the second set of pixel values representative of light reflected from a scene including background light and light originating from other camera light sources; and

determining a third set of pixel values representative of light reflected from a scene based on a function of the first set of pixel values and the second set of pixel values.

2. The method of claim 1 , wherein generating the first set of pixel values comprises:

measuring a first subset of pixel values using the image sensor that are representative of light reflected from a scene including light originating from the camera system, background light, and light originating from other camera light sources;

generating a second subset of pixel values by interpolating the first subset of pixel values; and

generating the first set of pixels based on the first subset of pixel values and the second subset of pixel values.

3. The method of claim 2 , wherein generating the second set of pixel values comprises:

measuring a third subset of pixel values using the image sensor that are representative of light reflected from a scene including background light, and light originating from other camera light sources;

generating a fourth subset of pixel values by interpolating the third subset of pixel values;

generating the second set of pixels based on the third subset of pixel values and the fourth subset of pixel values.

4. The method of claim 3 , wherein generating the third set of pixel values comprises subtracting the second set of pixel values from the first set of pixel values.

5. The method of claim 3 , wherein:

the first subset comprises pixel values representative of pixels from even rows of the light sensor;

the second subset comprises pixel values based on interpolated pixel values from the even rows of the light sensor;

the third subset comprises pixel values representative of pixels from odd rows of the light sensor; and

the fourth subset comprises pixel values based on interpolated pixel values from the odd rows of the light sensor.

6. The method of claim 1 , further comprising generating a sequence, the sequence comprising a plurality of high values and plurality of low values and comprising a sequence length; and

wherein:

generating the first set of pixel values comprises activating a light source and a shutter based on a high value of the sequence; and generating the second set of pixel values comprises activating a shutter based on a low value of the sequence.

7. The method of claim 6 , wherein generating the sequence comprises generating a pseudo-random sequence.

8. The method of claim 7 , wherein the pseudo-random sequence comprises at least part of a Gold sequence.

9. The method of claim 6 , wherein generating the sequence comprises:

selecting a template sequence length that is smaller than the sequence length;

generating a template sequence comprising a length equal to the selected template sequence length;

generating the sequence having the sequence length by repeating the template sequence.

10. The method of claim 9 , wherein generating the template sequence comprises:

generating a sub-sequence having a length that is half of the template sequence length;

generating a complementary sub-sequence to the sub-sequence that is half of the template sequence length; and

generating the template sequence by concatenating the sub-sequence and the complementary sub-sequence.

11. The method of claim 10 , wherein the sub-sequence comprises a sequence of equal values.

12. The method of claim 1 , further comprising:

sensing, by the light sensor of the imaging system, light received during a time period;

processing the light received by the light sensor;

identifying an available measurement period for the imaging system within the time period based on the processed light; and

transmitting and receiving light during a corresponding measurement period in one or more subsequent time periods.

13. The method of claim 12 , wherein processing the light received comprises creating a time series waveform representative of the light received within the time period.

14. The method of claim 13 , wherein identifying an available measurement period comprises:

correlating the time series waveform with a time window to create a correlation waveform.

15. The method of claim 14 , wherein identifying an available measurement period comprises:

identifying a period during which the correlation waveform indicates a lowest level of interference.

16. The method of claim 14 , wherein identifying an available measurement period comprises:

identifying a period during which the correlation waveform indicates a level of interference below a threshold level of interference.

17. The method of claim 16 , wherein identifying an available time slot from among the set of time slots:

creating a time series waveform representative of the light received within the time period

accumulating values of the time series waveform in each time slot; and

identifying a time slot that exhibits a lowest accumulated value among the time slots.

18. A camera apparatus comprising:

a light source;

a light detection circuit to sense, by the light detection circuit, light received during a time period;

control logic to:

generate a first set of pixel values, the first set of pixel values representative of light received from a scene by a light sensor including light originating from the camera, background light, and light originating from other camera light sources;

generate a second set of pixel values, the second set of pixel values representative of light reflected from a scene including background light and light originating from other camera light sources; and

determine a third set of pixel values representative of light reflected from a scene based on a function of the first set of pixel values and the second set of pixel values.

19. The camera apparatus of claim 18 , the control logic configured to:

sense, by the light sensor of the imaging system, light received during a time period;

process the light received by the light sensor;

identify an available measurement period for the imaging system within the time period based on the processed light; and

transmit and receive light during a corresponding measurement period in one or more subsequent time periods.

20. The camera apparatus of claim 18 , wherein generating the first set of pixel values comprises:

measuring a first subset of pixel values using the image sensor that are representative of light reflected from a scene including light originating from the camera system, background light, and light originating from other camera light sources;

generating a second subset of pixel values by interpolating the first subset of pixel values; and

generating the first set of pixels based on the first subset of pixel values and the second subset of pixel values.

21. The camera apparatus of claim 20 , wherein generating the second set of pixel values comprises:

measuring a third subset of pixel values using the image sensor that are representative of light reflected from a scene including background light, and light originating from other camera light sources;

generating a fourth subset of pixel values by interpolating the third subset of pixel values;

generating the second set of pixels based on the third subset of pixel values and the fourth subset of pixel values.

22. The camera apparatus of claim 21 , wherein generating the third set of pixel values comprises subtracting the second set of pixel values from the first set of pixel values.

23. The camera apparatus of claim 21 , wherein:

the first subset comprises pixel values representative of pixels from even rows of the light sensor;

the second subset comprises pixel values based on interpolated pixel values from the even rows of the light sensor;

the third subset comprises pixel values representative of pixels from odd rows of the light sensor; and

the fourth subset comprises pixel values based on interpolated pixel values from the odd rows of the light sensor.

24. The camera apparatus of claim 18 , the control logic further configured to generate a sequence, the sequence comprising a plurality of high values and plurality of low values and comprising a sequence length; and

wherein:

generating the first set of pixel values comprises activating a light source and a shutter based on a high value of the sequence; and generating the second set of pixel values comprises activating a shutter based on a low value of the sequence.

25. The camera apparatus of claim 24 , wherein generating the sequence comprises generating a pseudo-random sequence.

26. The camera apparatus of claim 25 , wherein the pseudo-random sequence comprises at least part of a Gold sequence.

27. The camera apparatus of claim 24 , wherein generating the sequence comprises:

selecting a template sequence length that is smaller than the sequence length;

generating a template sequence comprising a length equal to the selected template sequence length;

generating the sequence having the sequence length by repeating the template sequence.

28. The camera apparatus of claim 27 , wherein generating the template sequence comprises:

generating a sub-sequence having a length that is half of the template sequence length;

generating a complementary sub-sequence to the sub-sequence having a length that is half of the template sequence length; and

generating the template sequence by concatenating the sub-sequence and the complementary sub-sequence.

29. The camera apparatus of claim 28 , wherein the sub-sequence comprises a sequence of equal values.