Influence of the Curved Surface on Surface Roughness Measurement Using Dichromatic Speckle Pattens

To study the influence of curved surface on the method of dichromatic speckle autocorrelation measuring surface roughness, curvature radius of surface is introduced. In this paper, the rough surface and the dichromatic speckle patterns are simulated, and the effects of different radius of curved surface on speckle patterns and speckle elongation ratio are discussed. The results show that the factor of surface radius is valid in dichromatic speckle autocorrelation measurement. Moreover, the larger curvature radius is, the larger speckle elongation becomes, and the smaller the deviation of measured surface roughness is. Therefore, influence of curvature of rough surface on measurement precision should be taken into consideration during measuring process.