Speckle Reduction for Ophthalmic OCT Images Based on Wavelet Filtering Technique

Speckle is a major factor that degrades the contrast and resolution of ophthalmic optical coherence tomography images. In this paper, we present a speckle reduction method for ophthalmic OCT images based on wavelet decomposition and reconstruction. Here, the Otsu algorithm is introduced for the calculation of a threshold to distinguish signals and speckles roughly, and the correlations of neighboring wavelet coefficients and the coefficients of the corresponding locations in different decomposition levels are used to suppress the speckle noise. The experimental results show that our method can improve the contrast of the ophthalmic OCT images significantly without unbearable image sharpness loss.