Abstract: The disclosure describes flicker detection and correction techniques to improve the quality of captured imagery, such as video or still images. In particular, this disclosure describes flicker correction techniques that compare different image frames to detect flicker. In some embodiments, the comparisons involves summing intensity values associated with rows within the frames and comparing the row sums to generate a difference signal. Detection and correction of flicker may be performed using a first derivative of the difference signal. The first derivative of the difference signal can be used in variety of ways to detect and correct flicker.

Abstract: Apparatus are provided, including an autofocus mechanism. The autofocus mechanism includes an autofocus preliminary operation mechanism and an autofocus continuation mechanism. The autofocus preliminary operation mechanism starts an autofocus of a lens assembly on a given target by causing a focus quality determiner to determine the quality of focus of the lens assembly on the given target while the position of the lens unit is in one focus range and causing an adjustment controller to effect a preliminary adjustment of the lens assembly position within the same one focus range. The autofocus continuation mechanism automatically, upon a lack of successful focus by the autofocus preliminary operation mechanism, continues an autofocus of the lens assembly on the given target by causing the adjustment controller to effect a continued adjustment of the lens assembly position from the one focus range to a different focus range while the focus quality determiner continues to determine the quality of the focus.