Nowadays, forensic watermarks are introduced at projection time in movie theater. This provides the Entertainment industry with a tracing mechanism to identify indelicate cinema owners, who would have let camcorders enter their premises. However, the watermarking technologies deployed in film-based theaters and digital cinemas differ. For cost efficiency during forensic analysis, it is desirable to have a reliable oracle that can accurately discriminate between film and digital projection recordings. Prior work focused on tell-tale artifacts present in the luminance channel to build a classifier. In this paper, we investigate whether color information could also be exploited. We introduce a number of features that relate either to color saturation or color bias, and assess their discriminative power in a systematic fashion. Experimental results on a data set containing nearly 250 real-life full length camcorded movies suggest that the color bias seems to provide the highest classification potential.
展开▼
