Zhu Xueliang

Analysis of noise reduction characteristics of the diffuser surface roughness on interferometric images

Since the coherent noise in the interferometric system, the method of rotated diffuser would reduce the coherence of the light beam to suppress the noise of the interference image. By analyzing the coherent noise reduction characteristics of rotated diffuser with different surface roughness, the relationship between surface roughness and the noise contrast under different rotation speeds was simulated, and the effective roughness range with noise reduction effect would be selected. It would build a noise reduction system based on Fizeau interference, and collected and calculated the noise contrast of the interference image. The effective range of σh/λ was 0.2~0.5 when the rotation speed was 10r/s, while the effective range of σh/λ was 0.4~0.6 when the rotation speed is 100r/s. The experimental results showed that the surface roughness and wavelength ratio σh/λ of rotated diffuser increased when the noise contrast tended to 1, but the effective range of surface roughness decreases with the increase of the rotational speed of the diffuser.