Research progress of 3D measurement technology based on phase coding

Structured light has developed rapidly as a non-contact active three-dimensional measurement method. The phase coding method based on the principle of structured light embeds the codeword into the intensity of the fringe in the form of phase, which is insensitive to surface contrast, ambient light and camera noise due to the use of phase instead of intensity to determine the code word, so it has stronger robustness. The research progress of three dimensional measurement methods of phase-coding was reviewed, and the three-dimensional measurement principles based on phase encoding was summarized, including the design method of initial phase, the generation method of encoded fringes, phase calculation methods, acquisition and correction of fringe order, and acquisition of absolute phase. Some experimental results were given, and the advantages and disadvantages of the phase coding method were pointed out. Finally, the challenges faced by the technology were discussed, and the future development direction of the field was pointed out.