An Efficient Algorithm to Select Reference Views for Virtual View Synthesis

View synthesis is one of the key techniques for generating immersive media. Virtual view synthesis techniques require considerable input views to provide a wide viewing space to users, such as 360 virtual reality. However, the computational complexity is increased, and the synthesized virtual image is blurred when all input views are used as reference views. We analyzed the algorithm complexity and synthesized image quality according to the number of reference pictures. Based on the results, we propose a systematic algorithm to compose an optimal subset of the reference pictures to reduce the hole area and increase the accuracy of the overlapped pixel data in the virtual view. The algorithm consists of the screening and optimal composing steps, which involve logical and geometric measurements. The experimental results demonstrate that the proposed method reduces algorithm complexity and improves the virtual view quality.