Methods and apparatus for defocus reduction using laser autofocus

An imaging apparatus comprising:

• a lens, configured to focus light from a scene at a focal plane of the lens;
• an image sensor, positioned approximately at the focal plane of the lens, configured to capture a plurality of frames depicting the scene based on the focused light from the scene;
• a distance sensor, configured to detect a distance between an object of the scene and the imaging device;
• a processor, operably coupled to the image sensor and lens;
• and
• a memory component, operably coupled to the processor, the processor, the distance sensor, and the memory component collectively configured to:
• prior to initiating an autofocus search operation, detect a change in the scene, and while the scene is changing:
• capture, with the imaging device, the plurality of frames depicting the scene, a portion of the scene corresponding to the object;
• for each of the plurality of frames:
• determine, using the distance sensor, a distance between the object and the imaging device;
• determine a lens position for the frame based on the determined distance by converting the determined distance for each frame to a lens position for each frame, the determined lens position being an estimate of the position of the lens for optimum focus of light propagating through the lens to the imaging device for the determined distance;
• and
• move the lens towards the determined lens position while the scene is changing;
• and
• in response to determining the scene is no longer changing for a predetermined duration, initiate an autofocus search operation.

An apparatus for reducing defocus events occurring during autofocus search operations, the apparatus comprising:

• a means for detecting a change in a scene;
• a means for capturing a plurality of frames depicting the scene while the scene is changing prior to initiating an autofocus search operation, a portion of the scene corresponding to an object;
• a means for determining a distance between the object and the imaging device for each frame of the plurality of frames;
• a means for determining a lens position for each frame based on the determined distance for each frame by converting the determined distance for each frame to a lens position for each frame, the determined lens position being an estimate of the position of the lens for optimum focus of light propagating through the lens to the imaging device for the determined distance frame;
• a means for moving the lens toward the lens position determined for each frame while the scene continues to change;
• a means for determining the scene is no longer changing for a predetermined duration;
• and
• a means for initiating an autofocus search operation based on the determination that the scene is no longer changing for the predetermined duration.

A non-transitory computer readable medium comprising instructions that when executed cause a processor to perform a method for reducing defocus events occurring during autofocus search operations, the method comprising:

• prior to initiating an autofocus search operation, detecting a change in a scene, and while the scene is changing:
• capturing, with an imaging device, a plurality of frames depicting the scene, a portion of the scene corresponding to an object;
• for each of the plurality of frames:
• determining, using a distance sensor, a distance between the object and the imaging device;
• determining a lens position for the frame based on the determined distance by converting the determined distance for each frame to a lens position for each frame, the determined lens position being an estimate of the position of the lens for optimum focus of light propagating through the lens to the imaging device for the determined distance;
• and
• moving the lens toward the determines lens position while the scene is changing;
• and
• in response to determining the scene is no longer changing for a predetermined duration, initiating an autofocus search operation.