Exposing Image Resizing utilizing Welch Power Spectral Density Analysis for Double Compressed JPEG Images

Abstract

This paper addresses the problem of forensic analysis of recompressed images in the presence of image resizing, particularly the estimation of the resizing factor by which the image underwent resizing. The proposed method analyzes the Welch power spectral density for presence of peaks introduced by double JPEG artefacts in-order to arrive at the correct resizing factor. The correct resizing factor estimation serves as an important forensic clue since it provides vital information on the life history of the image. Experimental validation carried out utilizing several double compressed JPEG images taken from heterogeneous datasets along with comparative analysis with an existing method shows superior performance for the proposed method.