Median Filtering Detection Using Ensemble Methods

Passive image forgery techniques are aimed at detecting image tampering without any a prior knowledge about the images. One of the major challenges in the field of image forensics is detection of basic operators such as application of median filtering. Median filter is one of the basic operators that is being used for malicious intent of hiding history of operations applied on an image. The studies related to detection of median filtering are becoming very popular in the field of digital image forensics. A large number of methods have been proposed for detection of median filtering. The paper presents improved percentage streak area based on streak effect in median filtered images. An ensemble classifier is used for detection of median filtered images by performing a multi class classification using bagged method with decision tree as weak learner. The results show that the classifier performs better than state-of-the-art methods for multiclass classification between original, median filtered and postJPEG compressed median filtered images.