Depth Image Enhancement and Detection on NSCT and Fractional Differential

For enhancing the low contrast and detecting the noise in depth image from Kinect sensor, the Non-Subsampled Contourlet Transform (NSCT) and non-linear fractional differential are studied in this paper. Firstly, on the basis of the NSCT's advantages, the depth image is decomposed into low frequency and high frequency. The low frequency component is applied to enhance depth image using adaptive scale Retinex, and the scale parameter is adjusted by local mean and standard deviation. The high frequency component is calculated by Non-Local-Means operator to preserve the texture detail. The final enhanced image can be achieved by inverse NSCT. Secondly, the fractional differential theory is studied to accomplish noise detection. The experimental results show that the proposed method can enhance the depth image and detect noise effectively.