In free viewpoint video systems,enough viewpoints are obtained for au dience by depth image based rendering technique,where texture video and corresponding depth video are used.However,the quality of depth video is poor due to the limitation of depth video capture tech nologies.To enhance the quality of depth video,a depth processing algorithm based on feature analyses is proposed in this paper.Firstly,the depth video is adaptively divided into five clusters by fuzzy C-means (FCM) chustering,and the edges of depth video are detected and enlarged at the same time.Secondly,for p ixels in non-edge regions,a novel trilateral filter and a horizontal median filter are respectiv ely adopted according to features of each cluster.Finally,the corners in texture video and depth video are detected and enlarged. For pixel in edge area,median filters with different window sizes are selected according to whether the pixel is in corner area of both texture and depth video or not.Experimental res ults show that the objective quality of the virtual view can be increased by 0.43dB on average compared with that using original depth video while the subjective quality can be improved obviously.No matter in subje ctive quality or objective quality,the algorithm in this paper is much more effi cient than the Martin′s method.