Three dimensional measurement method combining color trapezoidal phase-shifting with color gray code

By combining the color trapezoidal phase-shifting with the Gray code, a color structured light three-dimensional measurement method was presented to achieve a fast high-resolution non-contact 3D measurement. In the measurement, the measured space was encoded and decoded by combining a color trapezoidal three-step phase-shifting pattern with two color gray code patterns. The measured space was divided into 64 sub-spaces by two color gray code patterns. Then, the each sub-space was divided into 6 regions by a repeat color trapezoidal three-step phase-shifting pattern, and each region was subdivided into the pixel through the intensity ratio. The encoding patterns and the decoding formulas were provided, and the color structured-light three-dimensional measurement system was set up. Furthermore, the planes with the depth of 700~950 mm were measured by the proposed method and a color trapezoidal phase-shifting method, respectively. The theoretical analysis, simulation and actual measurement results indicate that the measurement average error of planes is less than 0.9 mm and the measurement standard deviation is less than 1.2 mm. Finally the proposed method was also used in measuring the plaster face and a real hand, and the results show that this method has advantages in a strong anti-interference ability and fast computing speed.