Denoising for 3-D Photon-Limited Imaging Data Using Nonseparable Filterbanks
In this paper, we present a novel frame-based denoising algorithm for photon-limited 3D images. We first construct a new 3D nonseparable filterbank by adding elements to an existing frame in a structurally stable way. In contrast with the traditional 3D separable wavelet system, the new filterbank is capable of using edge information in multiple directions. We then propose a data-adaptive hysteresis thresholding algorithm based on this new 3D nonseparable filterbank. In addition, we develop a new validation strategy for denoising of photon-limited images containing sparse structures, such as neurons (the structure of interest is less than 5% of total volume). The validation method, based on tubular neighborhoods around the structure, is used to determine the optimal threshold of the proposed denoising algorithm. We compare our method with other state-of-the-art methods and report very encouraging results on applications utilizing both synthetic and real data.