Detect piecewise linear contrast enhancement and estimate parameters using spectral analysis of image histogram

Linear contrast enhancement is a common procedure for expanding or reducing dynamic range of the image gray values. We propose a method to detect global linear contrast enhancement to be used as a technique for digital image authentication. We show that a linear mapping operation introduces periodic artifacts into the histogram, and the period is related to the mapping function. We develop an algorithm to estimate the parameters of a three-section polyline mapping function. Experimental results show effectiveness of the proposed algorithms.