Optical image stabilization calibration

1. A camera module, the camera actuator module comprising:

a linear actuator motor for moving a lens assembly;

a position sensor coupled to the lens assembly;

a mechanical end stop mounted in a path of motion of the lens assembly; and

a non-transitory storage medium storing program instructions, wherein the program instructions are computer-executable to implement:

exciting, using the linear actuator motor, a mechanical resonance in the camera actuator module calculated to cause the lens assembly to move to an overload displacement by powering the linear actuator of the camera actuator module at a resonant frequency of the camera actuator module,

measuring, using the position sensor, a current maximal displacement of the lens assembly during the exciting, and

estimating a position of the mechanical end stop using at least the current maximal displacement.

2. The camera module of claim 1 , wherein the non-transitory storage medium further comprises program instructions computer-executable to implement:

providing optical image stabilization, wherein the program instructions computer-executable to implement the providing optical image stabilization comprise:

program instructions computer-executable to implement calculating a maximum safe stabilization motion using the position of the mechanical end stop, and

program instructions computer-executable to implement the camera actuator module applying the maximum safe stabilization motion.

3. The camera module of claim 1 , wherein

The program instructions computer-executable to implement the exciting the mechanical resonance calculated to cause the actuator module to move to the overload displacement further comprise:

program instructions computer-executable to implement exciting the mechanical resonance calculated to cause the actuator module to move to a displacement beyond displacements achievable by the actuator module at a steady state.

4. The camera module of claim 1 , wherein

program instructions computer-executable to implement the powering the linear actuator of the camera actuator module at the resonant frequency of the camera actuator module further comprise:

program instructions computer-executable to implement powering a linear actuator motor of the camera actuator module at the resonant frequency of the camera actuator module.

5. The camera module of claim 1 , wherein

the linear actuator comprises a voice coil motor for moving a lens assembly of the camera module.

6. The camera module of claim 1 , wherein

the position sensor comprises a Hall sensor for measuring a position of a component of the camera module.

7. A method for operating a camera component, comprising:

exciting a mechanical resonance in a camera actuator module calculated to cause the camera actuator module to move to an overload displacement by powering a linear actuator of the camera actuator module at a resonant frequency of the camera actuator module;

measuring a current maximal displacement of the actuator module during the exciting; and

estimating a position of a mechanical end stop using at least the current maximal displacement, wherein the mechanical end stop is mounted in a path of motion of the camera actuator module.

8. The method of claim 7 , further comprising,

characterizing the camera actuator module, wherein the characterizing the camera actuator module further comprises:

measuring physical properties of the camera actuator module, and

storing variables representing the physical properties of the camera actuator module in a memory associated with the camera actuator module.

9. The method of claim 7 , further comprising providing optical image stabilization, wherein the providing optical image stabilization comprises:

calculating a maximum safe stabilization motion using the position of the mechanical end stop, and

the camera actuator module applying the maximum safe stabilization motion.

10. The method of claim 7 , wherein the exciting the mechanical resonance calculated to cause the actuator module to move to the overload displacement further comprises:

exciting the mechanical resonance calculated to cause the actuator module to move to a displacement beyond displacements achievable by the actuator module at a steady state.

11. The method of claim 7 , wherein the estimating the position of the mechanical end stop using at least the maximal displacement further comprises:

estimating an actuator-unachievable position of the mechanical end stop, wherein

the actuator unachievable position of the mechanical end stop is a position beyond a position range achievable by the drive power of the linear actuator.

12. The method of claim 7 , wherein the powering the linear actuator of the camera actuator module at the resonant frequency of the camera actuator module further comprises:

powering a linear actuator motor of the camera actuator module at the resonant frequency of the camera actuator module.

13. The method of claim 7 , wherein the powering the linear actuator of the camera actuator module at the resonant frequency of the camera actuator module further comprises:

powering the linear actuator of the camera actuator module at the resonant frequency of the camera actuator module at a resonant frequency associated with one or more springs in the actuator module.

14. The method of claim 7 , wherein the estimating the position of the mechanical end stop using at least the maximal displacement further comprises:

estimating the position of the mechanical end stop using at least the maximal displacement using the position sensor measurements and a physical system model of the actuator module.

15. A non-transitory computer-readable storage medium storing program instructions, wherein the program instructions are computer-executable to implement:

exciting a mechanical resonance in a camera actuator module calculated to cause the camera actuator module to move to an overload displacement by powering a linear actuator of the camera actuator module at a resonant frequency of the camera actuator module;

measuring a current maximal displacement of the actuator module during the exciting; and

estimating a position of a mechanical end stop using at least the current maximal displacement, wherein the mechanical end stop is mounted in a path of motion of the camera actuator module.

16. The non-transitory computer-readable storage medium of claim 15 , further comprising:

program instructions computer-executable to implement characterizing the camera actuator module, wherein the program instructions computer-executable to implement characterizing the camera actuator module further comprise:

program instructions computer-executable to implement measuring physical properties of the camera actuator module, and

program instructions computer-executable to implement storing variables representing the physical properties of the camera actuator module in a memory associated with the camera actuator module.

17. The non-transitory computer-readable storage medium of claim 15 , further comprising program instructions computer-executable to implement providing optical image stabilization, wherein the program instructions computer-executable to implement the providing optical image stabilization comprise:

program instructions computer-executable to implement calculating a maximum safe stabilization motion using the position of the mechanical end stop, and

program instructions computer-executable to implement the camera actuator module applying the maximum safe stabilization motion.

18. The non-transitory computer-readable storage medium of claim 15 , wherein the program instructions computer-executable to implement exciting the mechanical resonance calculated to cause the actuator module to move to the overload displacement further comprise:

program instructions computer-executable to implement exciting the mechanical resonance calculated to cause the actuator module to move to a displacement beyond displacements achievable by the actuator module at a steady state.

19. The non-transitory computer-readable storage medium of claim 15 , wherein the program instructions computer-executable to implement estimating the position of the mechanical end stop using at least the maximal displacement further comprise:

program instructions computer-executable to implement estimating an actuator-unachievable position of the mechanical end stop, wherein

the actuator unachievable position of the mechanical end stop is a position beyond a position range achievable by the drive power of the linear actuator.

20. The non-transitory computer-readable storage medium of claim 15 , wherein the program instructions computer-executable to implement powering the linear actuator of the camera actuator module at the resonant frequency of the camera actuator module further comprise:

program instructions computer-executable to implement powering a linear actuator motor of the camera actuator module at the resonant frequency of the camera actuator module.