Robust Median Filtering Detection Based on Filtered Residual

Abstract

AbstractIn multimedia forensics, exposing an image’s processing history draws much attention. Median filtering is a popular noise removal tool, which has been used as a popular anti-forensics tool recently. An image is usually saved in a compressed format such as the JPEG format. While the detection of median filtering from a JPEG compressed image is difficult because typical filter characteristics are suppressed by JPEG quantization and block artifacts. In this paper, we introduce a novel forensic trace – median filter residual. Median filtering is first applied on a test image, and the difference between the initial image and the filtered output image is called the median filter residual. The filtered residual is used as the forensic fingerprint. Thus, the interference from the image edge and texture which is regarded as a major limitation of the existing forensic methods can be reduced. Experimental results on a large image database show that the proposed method is very robust to JPEG post- compression, and achieves much better performance than the existing state-of-the-art works.KeywordsDigital image ForensicsMedian filter residualTransition probability