Speckle Reduction by Optical Pre-processing and Digital Filtering in Digital Holography
J-M. Leng, F-B. Li and H-L. Li
A method is proposed to suppress speckle in a digital hologram by integrating optical pre-process and digital filtering algorithm. Three optical de-noising ways are set up and analysed at first. The optimal method is adopted to smooth speckle noise and to change the statistical property of speckle in the reconstructed image. Then an adaptive filtering algorithm is designed to further de-noise. The de-noising effect of the method is quantitatively evaluated. Experimental results confirm the feasibility and effectiveness of the proposed method. The proposed method can be applied into the fields such as three-dimensional imaging, holographic measure, medical diagnosis and the like.
Keywords: He-Ne laser, speckle, optical information processing, digital filter, holography, varying polarization, analogous patch