Color Trapezoidal Phase-shifting Intensity Ratio 3D Measurement Method

There is broad prospect in areas such as 3D non-contact measurement about structured light 3D measurement technique. Color trapezoidal phase-shifting projection method is a structured light 3D measurement technique. There are some advantages which include non-contact, high-resolution, non-destructive and data acquisition fast, 3D coordinate measurement can be implemented fast with it. In this paper we design the contour measurement system based on color trapezoid phase-shifting projection method for the measured object in a static or quasi-static situation.In this paper we study deep color trapezoidal phase-shifting coding and decoding method and other aspects. There are broad application prospects in industrial design, production control, medical testing and archaeological areas about research results. Major research in the paper as follows:A 3D measurement system mathematical mode is established according to this method. We designed the 3D shape measurement system which includes DLP projector,3-CCD camera and notebook computers.We Proposed color trapezoidal phase-shifting technique by combing gray trapezoidal phase-shifting method with RGB color space model. Color trapezoidal phase-shifting method only needs a color trapezoidal fringe pattern to carry out intensity ratio measurements. It greatly reduces the measurement time compared with gray trapezoidal phase-shifting method.We researched modulation and demodulation algorithm of intensity ratio based on color trapezoidal phase-shifting method. We proposed color gray code combined with color trapezoidal phase-shifting measurement method to improve anti-jamming capability. We study deep the time-domain expansion technique based on color gray code to extract unwrapped intensity ratio.We carried out 3D measurement simulation experiments and actual experiments. Experimental results show that: Maximum measurement error is 2.1484mm in the context of 700-950mm depth, reconstruction of the complex surface has a good visual effect.We studied deep color compensation key technologies, analyze and solve specific issues which occurred in the actual measurement, and provides a strong support to improve the measurement accuracy of the device in the actual measurement.We analyzed deeply the color coupling and imbalances problems which occurred in the process of the experiments, and give the solution to them. It improved the measurement accuracy of the measurement system in the process of actual measurement.In this paper, we provided high accuracy and high sampling density and its theoretical and experimental basis for coding structured light 3D measurement, There is a great significance for improving the development and engineering application of structured light 3D measurement technology.