An Evaluation Framework For Digital Image Forensics Tools

The boom of digital cameras, photography, and social media has drastically changed how humans live their day-to-day, but this normalization is accompanied by malicious agents finding new ways to forge and tamper with images for unlawful monetary (or other) gains. Disinformation in the photographic media realm is an urgent threat. The availability of a myriad of image editing tools renders it almost impossible to differentiate between photo-realistic and original images. The tools available for image forensics require a standard framework against which they can be evaluated. Such a standard framework can aid in evaluating the suitability of an image forensics tool for use in a criminal investigation, commercial operation, or academic research. This paper proposes an evaluation framework designed for image forensics tools based on the conformance methodology of testing that employs test assertions and test cases. It is then used to evaluate four image forensics tools namely FotoForensics, Ghiro, Imago Forensics, and Exif Reader. The comparative insight of test results produced by the framework provides a ground for ranking the tools from best to least comprehensive. The results also provide information necessary for users to make intelligent choices about tools and help vendors shortlist areas of improvement in their tools.