Speckle noise suppression of digital holographic microscopy with diffusion glass rotation

Digital holographic microscopy is an ideal non-invasive, non-contact, and fast-response 3D measurement method. The strong coherence of the laser leads to irregularly distributed speckle noise during the digital holographic recording process, which affects the 3D reconstruction of the digital holographic microscopy system. To solve this problem, the coherence of the laser is changed by diffusion glass rotation to achieve the suppression of the speckle noise in the digital holographic measurement system. Firstly, a theoretical model of a digital holographic microscopy system based on the diffusion glass rotation is established. Then, the influence of diffusion glass rotation speed on coherence time, speckle contrast, fringe contrast, signal-to-noise ratio are simulated and analyzed, the optimal rotation speed of the digital holographic microscopy system is obtained. Finally, The speckle noise suppression system based on the Mach-Zehnder interference model is established, and the optimal parameters of the diffusion glass rotation are set, which verifies that the method is suitable for high-precision measurement.