Laser speckle noise suppression method based on empirical mode decomposition

In order to suppress the influence of laser speckle noise on the accuracy of quantitative phase reconstruction，a laser speckle noise suppression method based on empirical mode decomposition is proposed in this paper. The method only needs to acquire a holographic image without adding additional hardware equipment and avoids the complicated process of finding optimal processing parameters. Firstly，empirical mode decomposition is used to highlight image details. Secondly，edge detection is used to overcome the problems of poor anti-noise capability and the inability to identify false edges of gradient operators in the anisotropic diffusion equation，and edge detection is performed on images with prominent details. Finally， the diffusion denoising process is guided by the high-precision edge detection results to achieve better speckle suppression. The experimental results show that after processing by the method in this paper，the structural similarity of the reconstructed phase is increased by 12. 900 0%，the edge preservation index is increased by 14. 386 1%，the speckle suppression index is reduced by 8. 129 9%，and the phase cross-section curve is the closest to the original phase. The method proposed in this paper not only has a better denoising effect but also preserves the detailed information more effectively，and the accuracy of phase reconstruction is higher.