Perceptibility of digital watermarks embedded in 3D meshes using unimodal and bimodal hapto-visual interaction

In this paper, a study is conducted in order to measure and analyze the perceptibility of watermarks embedded in 3D meshes when (1) visual feedback is present, (2) haptic feedback is present, and (3) visual and haptic feedback are simultaneously available. More specifically, our experiments are intended to assess whether the use of a bimodal approach, where a subject is looking at, and touching a 3D mesh could in fact improve the perceptibility of a watermark as opposed to when only a single modality is available. The experiments are performed using a hapto-visual interface which integrates a haptic device with stereo graphics for an immersive high quality 3D experience. Overall, the results suggested that relying on bimodal hapto-visual feedback is better than any of the single modalities when detecting a watermark embedded in a 3D model. Further experiments with a greater number of subjects would however be necessary to better confirm this conclusion.