Motion vector field improvement for picture rate conversion with reduced halo The quality of the interpolated images in picture rate upconversion is predominantly dependent on the accuracy of the motion vector fields. Block based MEs typically yield incorrect vectors in occlusion areas, which leads to an annoying halo in the upconverted video sequences. In the past we have developed a costeffective block based motion estimator, the 3D Recursive Search ME, and an improved accuracy version for tackling occlusion, the tritemporal ME. In this article we describe how the vector field from this tritemporal ME is further improved by a retimer, using information from a foregroundbackground detector. More accurate motion vector fields are of importance to other applications also (e.g. video compression, 3D, scene analysis ...).

Spherical Video Coding With Motion Vector Modulation to Account For Camera Motion Emerging immersive multimedia applications critically depend on efficient compression of spherical (360degree) videos. Current approaches project spherical video onto planes for coding with standard codecs, without accounting for the properties of spherical video, a severe suboptimality that motivates this work. A common type of spherical video is dominated by camera translation. We recently proposed a powerful motion compensation technique for such videos which builds on the observation that, with camera translation, stationary points are perceived as moving along geodesics that meet at the point where the camera translation vector intersects the sphere. However, the approach follows standard coding procedures and translates all pixels in a block by the same amount on their respective geodesics, which is suboptimal. This paper analyzes the appropriate rate of translation along geodesics and its dependence on the elevation of a pixel on the sphere with respect to the camera velocity pole. The analysis leads to a new approach that modulates the effective motion vectors within a block such that they perfectly capture the perceived individual motion of each pixel. Consistent gains in the experiments provide evidence for the efficacy of the proposed approach.