Patent ID: 9734562
Date: 2017-08-15
CPC Classifications: G02B,G03B,G06K,G06T,H04N

Claim:
1. A method for generating a focus signal from a plurality of edges of an image of a scene to indicate a degree of image sharpness, comprising: rejecting or de-emphasizing a contribution from an edge towards the focus signal in a computing device depending on a quantity that represents a degree of reflection asymmetry in a sequence of gradients across the edge; and generating the focus signal, wherein any edge that makes a contribution towards the focus signal contributes an edge-sharpness measure that is a quantity computed from a plurality of samples of image data within a predetermined neighborhood of said any edge, wherein the edge-sharpness measure has a unit that is a power of a unit of length, given that distance between gradients and count of pixels both have a unit of length, gradient value has unit that is a unit of energy divided by a unit length, and normalized gradient values are unitless.