Roll compensation and blur reduction in tightly synchronized optical image stabilization (OIS)

1. A method of providing synchronized optical image stabilization in a camera assembly having an adjustable lens, the method comprising:

for an image sensor of the camera assembly with sensor elements disposed in rows oriented in a direction along an first axis and columns oriented in a direction along a second axis, obtaining information indicative of the beginning of a frame of the image sensor, wherein the frame comprises a period of time having an exposure period followed by a readout period in which exposure values are read from the sensor elements row by row; and

for each time of a plurality of times during the frame:

obtaining respective movement data indicative of rotation or translation of the camera assembly corresponding to the respective time;

determining a respective value of a time-dependent function based at least in part on the information indicative of the beginning of the frame, wherein the respective value of the time-dependent function is dependent on the respective time in relation to the frame; and

causing the adjustable lens to be moved to a respective position relative to the image sensor during the frame, wherein the respective position is based on the respective movement data and the respective value of the time-dependent function.

2. The method of claim 1 , wherein the time-dependent function is indicative of which row of sensor elements of the image sensor is exposed at a given time.

3. The method of claim 2 , wherein the time-dependent function is based on a number of rows of sensor elements of the image sensor.

4. The method of claim 1 , wherein:

the respective movement data is indicative of rotation of the camera assembly around a third axis orthogonal to the first axis and the second axis; and

for each time of the plurality of times during the frame, a location of the respective position in a direction along the first axis is at least partially based on the respective movement data and the respective value of a time-dependent function.

5. The method of claim 4 , wherein, for each time of the plurality of times during the frame, the location of the respective position in a direction along the second axis is at least partially based on the respective value of a time-dependent function.

6. The method of claim 1 , wherein:

the respective movement data is indicative of rotation of the camera assembly around a first axis; and

a location of the respective position in a direction along the second axis is at least partially based on the respective movement data and the respective value of a time-dependent function.

7. The method of claim 6 , wherein, for each time of the plurality of times during the frame, the location of the respective position in a direction along the first axis is at least partially based on the respective value of a time-dependent function.

8. The method of claim 1 , further comprising, determining a length of the exposure period and a length of the readout period.

9. The method of claim 8 , further comprising:

determining that the length of the exposure period does not exceed a threshold length in relation to the length of the readout period;

wherein determining the respective value of the time-dependent function for each time of the plurality of times during the frame is in response to determining that the length of the exposure period does not exceed the threshold length of the readout period.

10. The method of claim 8 , further comprising:

prior to the beginning of the frame, determining that a length of the exposure period exceeds a threshold length in relation to a length of the readout period; and

in response to determining that the length of the exposure period exceeds the threshold length of the readout period, decreasing the length of the exposure period such that the length of the exposure period does not exceed the threshold length of the readout period, and at least partially compensating for the decrease in the length of the exposure period by:

increasing an ISO of the image sensor,

widening an aperture of the camera assembly configured to adjust an amount of light to which the image sensor is exposed, or

both.

11. A camera assembly with optical image stabilization, the camera assembly comprising:

a controller configured to be communicatively coupled with:

an image sensor of the camera assembly with sensor elements disposed in rows oriented in a direction along an first axis and columns oriented in a direction along a second axis,

one or more actuators configured to move an adjustable lens that focuses light onto the image sensor; and

a motion sensor;

wherein the controller is configured to:

obtain information indicative of the beginning of a frame of the image sensor, wherein the frame comprises a period of time having an exposure period followed by a readout period in which exposure values are read from the sensor elements row by row; and

for each time of a plurality of times during the frame:

obtain respective movement data, from the motion sensor, indicative of rotation or translation of the camera assembly corresponding to the respective time;

determine a respective value of a time-dependent function based at least in part on the information indicative of the beginning of the frame, wherein the respective value of the time-dependent function is dependent on the respective time in relation to the frame; and

move, with the one or more actuators, the adjustable lens to a respective position relative to the image sensor during the frame, wherein the respective position is based on the respective movement data and the respective value of the time-dependent function.

12. The camera assembly of claim 11 , wherein the time-dependent function is indicative of which row of sensor elements of the image sensor is exposed at a given time.

13. The camera assembly of claim 12 , wherein the time-dependent function is based on a number of rows of sensor elements of the image sensor.

14. The camera assembly of claim 11 , wherein:

the respective movement data is indicative of rotation of the camera assembly around a third axis orthogonal to the first axis and the second axis; and

for each time of the plurality of times during the frame, the controller determines a location of the respective position in a direction along the first axis at least partially based on the respective movement data and the respective value of a time-dependent function.

15. The camera assembly of claim 14 , wherein, for each time of the plurality of times during the frame, the controller determines the location of the respective position in a direction along the second axis at least partially based on the respective value of a time-dependent function.

16. The camera assembly of claim 11 , wherein:

the respective movement data is indicative of rotation of the camera assembly around a first axis; and

the controller determines a location of the respective position in a direction along the second axis at least partially based on the respective movement data and the respective value of a time-dependent function.

17. The camera assembly of claim 16 , wherein, for each time of the plurality of times during the frame, the controller determines the location of the respective position in a direction along the first axis at least partially based on the respective value of a time-dependent function.

18. The camera assembly of claim 11 , wherein the controller is further configured to determine a length of the exposure period and a length of the readout period.

19. The camera assembly of claim 18 , wherein the controller is further configured to determine that the length of the exposure period does not exceed a threshold length in relation to the length of the readout period;

wherein the controller is configured to determine the respective value of the time-dependent function for each time of the plurality of times during the frame in response to determining that the length of the exposure period does not exceed the threshold length of the readout period.

20. The camera assembly of claim 18 , wherein the controller is further configured to:

prior to the beginning of the frame, determine that a length of the exposure period exceeds a threshold length in relation to a length of the readout period; and

in response to determining that the length of the exposure period exceeds the threshold length of the readout period, decrease the length of the exposure period such that the length of the exposure period does not exceed the threshold length of the readout period, and at least partially compensating for the decrease in the length of the exposure period by:

increasing an ISO of the image sensor,

widening an aperture of the camera assembly configured to adjust an amount of light to which the image sensor is exposed, or

both.

21. An apparatus comprising:

means for obtaining, for an image sensor of a camera assembly with sensor elements disposed in rows oriented in a direction along an first axis and columns oriented in a direction along a second axis, information indicative of the beginning of a frame of the image sensor, wherein the frame comprises a period of time having an exposure period followed by a readout period in which exposure values are read from the sensor elements row by row; and

means for, for each time of a plurality of times during the frame:

obtaining respective movement data indicative of rotation or translation of the camera assembly corresponding to the respective time;

determining a respective value of a time-dependent function based at least in part on the information indicative of the beginning of the frame, wherein the respective value of the time-dependent function is dependent on the respective time in relation to the frame; and

causing an adjustable lens to be moved to a respective position relative to the image sensor during the frame, wherein the respective position is based on the respective movement data and the respective value of the time-dependent function.

22. The apparatus of claim 21 , wherein the time-dependent function is indicative of which row of sensor elements of the image sensor is exposed at a given time.

23. The apparatus of claim 22 , wherein the time-dependent function is based on a number of rows of sensor elements of the image sensor.

24. The apparatus of claim 21 , wherein

the respective movement data is indicative of rotation of the camera assembly around a third axis orthogonal to the first axis and the second axis; and

the apparatus further includes, for each time of the plurality of times during the frame, means for determining a location of the respective position in a direction along the first axis at least partially based on the respective movement data and the respective value of a time-dependent function.

25. The apparatus of claim 24 , further comprising means for, for each time of the plurality of times during the frame, determining the location of the respective position in a direction along the second axis at least partially based on the respective value of a time-dependent function.

26. The apparatus of claim 21 , wherein:

the respective movement data is indicative of rotation of the camera assembly around a first axis; and

the apparatus further includes means for determining a location of the respective position in a direction along the second axis at least partially based on the respective movement data and the respective value of a time-dependent function.

27. The apparatus of claim 26 , further comprising means for, for each time of the plurality of times during the frame, determining the location of the respective position in a direction along the first axis at least partially based on the respective value of a time-dependent function.

28. The apparatus of claim 21 , further comprising means for determining a length of the exposure period and a length of the readout period.

29. The apparatus of claim 28 , further comprising:

means for determining that the length of the exposure period does not exceed a threshold length in relation to the length of the readout period;

wherein determining the respective value of the time-dependent function for each time of the plurality of times during the frame is in response to determining that the length of the exposure period does not exceed the threshold length of the readout period.

30. The apparatus of claim 28 , further comprising:

means for, prior to the beginning of the frame, determining that a length of the exposure period exceeds a threshold length in relation to a length of the readout period; and

means for, in response to determining that the length of the exposure period exceeds the threshold length of the readout period, decreasing the length of the exposure period such that the length of the exposure period does not exceed the threshold length of the readout period, and at least partially compensating for the decrease in the length of the exposure period by:

increasing an ISO of the image sensor,

widening an aperture of the camera assembly configured to adjust an amount of light to which the image sensor is exposed, or

both.

31. A non-transitory computer-readable medium having instructions embedded thereon for providing synchronized optical image stabilization in a camera assembly having an adjustable lens, the instructions, when executed by one or more processing units, cause the one or more processing units to:

for an image sensor of the camera assembly with sensor elements disposed in rows oriented in a direction along an first axis and columns oriented in a direction along a second axis, obtain information indicative of the beginning of a frame of the image sensor, wherein the frame comprises a period of time having an exposure period followed by a readout period in which exposure values are read from the sensor elements row by row; and

for each time of a plurality of times during the frame:

obtain respective movement data indicative of rotation or translation of the camera assembly corresponding to the respective time;

determine a respective value of a time-dependent function based at least in part on the information indicative of the beginning of the frame, wherein the respective value of the time-dependent function is dependent on the respective time in relation to the frame; and

cause the adjustable lens to be moved to a respective position relative to the image sensor during the frame, wherein the respective position is based on the respective movement data and the respective value of the time-dependent function.

32. The non-transitory computer-readable medium of claim 31 , wherein the time-dependent function is indicative of which row of sensor elements of the image sensor is exposed at a given time.

33. The non-transitory computer-readable medium of claim 32 , wherein the time-dependent function is based on a number of rows of sensor elements of the image sensor.

34. The non-transitory computer-readable medium of claim 31 , wherein the respective movement data is indicative of rotation of the camera assembly around a third axis orthogonal to the first axis and the second axis;

further comprising instructions that, when executed by one or more processing units, cause the one or more processing units to determine, for each time of the plurality of times during the frame, a location of the respective position in a direction along the first axis is at least partially based on the respective movement data and the respective value of a time-dependent function.

35. The non-transitory computer-readable medium of claim 34 , further comprising instructions that, when executed by one or more processing units, cause the one or more processing units to determine, for each time of the plurality of times during the frame, the location of the respective position in a direction along the second axis is at least partially based on the respective value of a time-dependent function.

36. The non-transitory computer-readable medium of claim 31 , wherein the respective movement data is indicative of rotation of the camera assembly around a first axis;

further comprising instructions that, when executed by one or more processing units, cause the one or more processing units to determine a location of the respective position in a direction along the second axis at least partially based on the respective movement data and the respective value of a time-dependent function.

37. The non-transitory computer-readable medium of claim 36 , further comprising instructions that, when executed by one or more processing units, cause the one or more processing units to determine, for each time of the plurality of times during the frame, the location of the respective position in a direction along the first axis at least partially based on the respective value of a time-dependent function.

38. The non-transitory computer-readable medium of claim 31 , further comprising instructions that, when executed by one or more processing units, cause the one or more processing units to determine a length of the exposure period and a length of the readout period.

39. The non-transitory computer-readable medium of claim 38 , further comprising instructions that, when executed by one or more processing units, cause the one or more processing units to:

determine that the length of the exposure period does not exceed a threshold length in relation to the length of the readout period;

wherein determining the respective value of the time-dependent function for each time of the plurality of times during the frame is in response to determining that the length of the exposure period does not exceed the threshold length of the readout period.

40. The non-transitory computer-readable medium of claim 38 ,

further comprising instructions that, when executed by one or more processing units, cause the one or more processing units to:

prior to the beginning of the frame, determine that a length of the exposure period exceeds a threshold length in relation to a length of the readout period; and

in response to determining that the length of the exposure period exceeds the threshold length of the readout period, decrease the length of the exposure period such that the length of the exposure period does not exceed the threshold length of the readout period, and at least partially compensating for the decrease in the length of the exposure period by:

increasing an ISO of the image sensor,

widening an aperture of the camera assembly configured to adjust an amount of light to which the image sensor is exposed, or

both.