Application of Benfordʼs Law to Images
This chapter analyzes the application of Benford's law to pictures taken from nature with a digital camera. Considering that many natural phenomena seem to follow Benford's law and that images are often nothing but “snapshots of nature,” it is pertinent to wonder whether images (at least those taken from nature) obey Benford's law. While the values output by the image capture device embedded in the camera, i.e., the pixels, do not follow Benford's law, this chapter shows that if they are transformed into a domain that better approximates the human visual system then the resulting values satisfy a generalized form of Benford's law. This can be used for image forensic applications, such as detecting whether an image has been modified to carry a hidden message (steganography) or has been compressed with some loss of quality.