A calibration method for LED point light sources in near-field photometric stereo

In near-field photometric stereo vision, the accurate calibration of the light source position directly affects the precision of the reconstruction results. Traditional calibration techniques rely on a highly reflective sphere and exploit the specular reflection properties at highlight points for determining light source positions. However, in real-world scenarios, nonuniform lighting conditions often leads to errors in extracting the sphere's image edges, affecting the accuracy of light source position calibration. Therefore, we propose a method for calibrating light source position based on a novel target. This method involves detecting planar reference points that are less sensitive to the lighting conditions and leveraging the pose relationship provided by the planar reference points to effectively overcome the adverse effects of lighting conditions on light source position calibration. Experimental results demonstrate that this method significantly enhances the precision of light source position calibration under non-uniform lighting conditions, eliminating the constraint of light source position calibration on specific lighting environments.