Abstract:
Binary pattern defocused projection is a widely used in traditional structured light 3D shape measurement method. However, the degree of defocusing increase with distance, which makes a limitation for high-accuracy 3D measurement. To slove the pronlem of deep defocusing and nonlinear Gamma effect, a novel method combining triangle pattern slight defocusing combine with phase shifting is proposed. The proposed method can either overcome the measurement error caused by nonlinear gamma or slightly defocusing to an ideal sinusoidal pattern in a short distance. Thus, the method prposed can effectively reduce the measurement error caused by deep defocusing and Gamma effect. The RMS error of the proposed method is <0.03 mm. Theory analysis and experiments demonstrate the feasibility and superiority of the proposed method.