Improved Accuracy of the 3D Measurement Method Utilizing Differential Modulation Based on Multi-Color Channel Fusion

The traditional structured light illumination measurement method usually utilizes peak detection and curve fitting to extract the target position of the modulation curve, while the modulation function is extremely insensitive to the variation of the peak position with height, which leads to the inability to further improve the measurement accuracy. Meanwhile, in the dual CCD detection system, there are problems such as signal matching, image matching, and difficult control of differential variables, which are also major difficulties and challenges. An improved-accuracy measurement method utilizing differential modulation based on multi-color channel fusion is proposed in this article, which adopts color CCD instead of black and white CCD in traditional measurement systems. By constructing a differential modulation measurement model and using the linear region with the highest slope of the differential modulation curve, the target position can be extracted based on the zero point localization method instead of the traditional peak localization method, which can successfully achieve further improvement in measurement accuracy. Simulation and experiments are carried out to verify the feasibility of the proposed method.