Autofocus method and autofocus device for its implementation

摘要

The invention relates to an autofocus method comprising adjusting a plurality of active windows comprising a central window and a plurality of border windows arranged around the central window and assigning weights to the plurality of active windows to calculate an autofocus value in each step; Calculating a rate of change in the autofocus value between a previous step and a current step from the autofocus value calculated in each step; Comparing the calculated rate of change in the autofocus value with preset autofocus reference values and then changing a step size according to the comparison resu Moving a lens to a position corresponding to the changed pitch; Repeating the above operations from setting the plurality of active windows to shifting the lens until the autofocus value of the previous step is greater than the autofocus value of the current step, and then determining whether the maximum autofocus value is detected; and moving the lens to a position corresponding to the maximum autofocus value.