Multi-resolution depth image restoration

Depth degradation caused by the conditions and environment of depth sensor hardware restricts its application potential, and this limitation cannot be avoided simply by improving the design of sensor. To overcome this limitation, we propose a multi-resolution depth image restoration method. Firstly, the sub-images of depth image and color image at different scales are obtained by multi-resolution analysis based on two-dimensional discrete wavelet transform. The multi-resolution joint bilateral filtering is then applied to the approximation low-frequency sub-image of the decomposed image. At the same time, using color-guided filtering method to restore high-frequency sub-images can effectively suppress edge artifacts without adding extra time burden. The high-quality output image is finally reconstructed using two-dimensional inverse discrete wavelet transform. A color guide image with rich edge information is introduced into the depth sub-image restoration to improve the depth image edge detail. Extensive experiments with synthetic and real datasets demonstrate that the proposed algorithm can effectively reduce additive Gaussian noise without losing sharp details in the noisy images and reduce the time consumption of depth image restoration.