Automated visual roughness evaluation of ground surface based on vertical incidence of circular structured light

In response to the significant influence of workpiece texture placement direction on the accuracy and reliability of visual roughness evaluation, a high-precision approach for measuring surface roughness using vertical incidence of circular structured light is proposed. Initially, the theory of vertical incidence method of circular structured light is described. Subsequently, the feasibility of the proposed imaging approach and its robustness against texture interference are validated using TRACEPRO simulations. The superiority of the proposed approach is confirmed by comparative analysis with oblique incidence method. An experimental setup is then designed based on the simulation model to capture images of samples with varying roughness and texture orientations. A model correlating structured light area features with roughness confirms the method's effectiveness and resistance to texture interference. Experimental results demonstrate that the proposed method effectively mitigates texture effects, achieving an average roughness prediction error of 0.02 μm.