METHOD AND APPARATUS FOR DERIVING A PERCEPTUAL HASH VALUE FROM AN IMAGE

摘要

A method and apparatus for deriving a hash value from a single channel image, comprising: size reducing (S21) the image into a series of first resized images having different horizontal and vertical size, deriving (S22) from each first resized image a horizontal difference image comprising horizontal neighboring pixel differences, size reducing (S31) the image into a sequence of second resized images having different horizontal and vertical size, deriving (S32) from each second resized image a vertical difference image comprising vertical neighboring pixel differences, and combining (S4, S5) the sign bits of the horizontal neighboring pixel differences and the sign bits of the vertical neighboring pixel differences in a predefined order into bits of the hash value.