A statistical model for quantized AC block DCT coefficients in JPEG compression and its application to detecting potential compression history in bitmap images

Abstract

We first develop a probability mass function (PMF) for quantized block discrete cosine transform (DCT) coefficients in JPEG compression using statistical analysis of quantization, with a Generalized Gaussian model being considered as the PDF for non-quantized block DCT coefficients. We subsequently propose a novel method to detect potential JPEG compression history in bitmap images using the PMF that has been developed. We show that this method outperforms a classical approach to compression history detection in terms of effectiveness. We also show that it detects history with both independent JPEG group (IJG) and custom quantization tables. © 2011 Springer-Verlag.