Adaptive autofocus lens positioning
View Patent ↗A method and system for effecting adaptive autofocusing, such as for a camera, are disclosed. The method can comprise obtaining focusing information, such as historic focusing information, storing the focusing information, and subsequently using the focusing information to facilitate a determination of a best position of a focusing lens during a focusing process. The use of such focusing information can result in a better choice for the next focusing lens position to be tested, such that the focusing process can be performed more rapidly.
1. A method for focusing, the method comprising:
storing image sharpness scores and corresponding focus lens positions for a plurality of previous photographs to form stored historic focusing information;
for a current photograph, determining a current image sharpness score and a corresponding current focus lens position;
comparing the current image sharpness score and the current focus lens position to the stored historic focusing information to determine an initial focus lens position; and
positioning a focus lens at the initial focus lens position.
2. The method as recited in claim 1 , wherein the historic focusing information further includes information regarding distances to subjects and corresponding focusing lens positions.
3. The method as recited in claim 1 , further comprising obtaining non-historic focusing information.
4. The method as recited in claim 1 , further comprising varying a position of the focus lens through a search range that includes the initial focus lens position to determine a best focus for the current photograph.
5. The method as recited in claim 1 , wherein the historic focusing information is stored in the memory as at least one lookup table.
6. An autofocus mechanism comprising:
a processor:
memory coupled to the processor for storing image sharpness scores and corresponding focus lens positions for a plurality of previous photographs to form stored historic focusing information; and
wherein the processor is configured to to compare a current image sharpness score and a current focus lens position to the historic focusing information to determine an initial focus lens position.
7. The autofocus mechanism as recited in claim 6 , wherein the processor is further configured to command a focus lens actuator to drive a focus lens to the initial focus lens position.
8. The autofocus mechanism as recited in claim 6 , wherein the historic focusing information comprises information regarding distances to subjects and corresponding focusing lens positions.
9. The autofocus mechanism as recited in claim 6 , wherein the processor is configured to use historic focusing information to facilitate a determination of a best position of a focusing lens during a focusing process, the historic information comprising best position history and sharpness score history.
10. The autofocus mechanism as recited in claim 6 , wherein the processor is further configured to use non-historic focusing information to facilitate a determination of a best position of a focusing lens during a focusing process.
11. The autofocus mechanism as recited in claim 6 , wherein the processor is configured to define a number of lens positions to search for best focus, the number of positions to search being smaller that the total number of lens positions.
12. The autofocus mechanism as recited in claim 6 , wherein the processor is configured to use the historic focusing information to determine a next lens position to check.
13. The autofocus mechanism as recited in claim 6 , wherein the processor is configured to use the historic focusing information to determine a next lens position to check in order to obtain additional information to be used in the autofocus process.