Calibration method for an extended depth-of-field microscopic structured light system

This paper presents a calibration method for a microscopic structured light system with an extended depth of field (DOF). We first employed the focal sweep technique to achieve large enough depth measurement range, and then developed a computational framework to alleviate the impact of phase errors caused by the standard off-the-shelf calibration target (black circles with a white background). Specifically, we developed a polynomial interpolation algorithm to correct phase errors near the black circles to obtain more accurate phase maps for projector feature points determination. Experimental results indicate that the proposed method can achieve a measurement accuracy of approximately 1.0 mu m for a measurement volume of approximately 2,500 mu m (W) x 2,000 mu m (H) x 500 mu m (D). (c) 2021 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement