Incremental depth upscaling using an edge weighted optimization concept

Precise scene depth information is a pre-requisite in three-dimensional television (3DTV), e.g. for high quality view synthesis in autostereoscopic multiview displays. Unfortunately, this information is not easily obtained and often of limited quality. Dedicated range sensors, such as time-of-flight (ToF) cameras, can deliver reliable depth information where (stereo-)matching fails. Nonetheless, since these sensors provide only restricted spatial resolution, sophisticated upscaling methods are sought-after, to match depth information to corresponding texture frames. Where traditional upscaling fails, novel approaches have been proposed, utilizing additional information from the texture for the depth upscaling process. We recently proposed the Edge Weighted Optimization Concept (EWOC) for ToF upscaling, using texture edges for accurate depth boundaries. In this paper we propose an important update to EWOC, dividing it into smaller incremental upscaling steps. We predict two major improvements from this. Firstly, processing time should be decreased by dividing one big calculation into several smaller steps. Secondly, we assume an increase in quality for the upscaled depth map, due to a more coherent edge detection on the video frame. In our evaluations we can show the desired effect on processing time, cutting down the calculation time more than in half. We can also show an increase in visual quality, based on objective quality metrics, compared to the original implementation as well as competing proposals.