Speckle reduction in Digital Holography by Fast Logistic Adaptive Non-local Means filtering

Digital holography is a promising imaging technology. However, there is speckle noise in the reconstructed image of a digital hologram. Speckle degrades the quality of the reconstructed image. Suppression of speckle noise is a challenging problem in digital holography. A novel method is proposed to reduce speckle by a fast Logistic adaptive Non-Local Means (NLM) algorithm. In the proposed method, the Logistic function is incorporated into the weight calculation of NLM algorithm to account for multiplicative speckle noise. Filtering parameters are dynamically adjusted according to the statistical property of speckle in the reconstructed image. To enhance computational efficiency, the proposed algorithm takes advantage of integral image technique to speed up the calculation of the similarity between image patches. Simulation and experiment are made to verify the proposed method. Results show that the speckle noise is effectively suppressed in the digital holography. The proposed method is efficient and feasible, which can be applied to such fields as three-dimensional display, holographic measurement, medical diagnosis and so on.