Abstract: In this paper,a Ray-Space interpolation algorithm based on directionalities of Ray-Space slice is proposed.Only the directionalities of characteristic pixels are detected from sparse Ray-Space slice,while directionalities of other pixels are interpolated from those directionalities of characteristic pixels in order to reduce the computational effort of directionality detection and to improve the accuracy.Sparse Ray-Space is then linearly interpolated along the directionalities to obtain dense Ray-Space for arbitrary viewpoint image rendering.Experimental results show that the proposed method can achieve good performance in Ray-Space interpolation,and significantly improve visual quality as well as PSNRs of rendered intermediate viewpoint image.