Accuracy Analysis of ToF and Structured Light with Different Baseline Lengths in the Mobile Smart Terminals

3D vision technique can digitize the real world and build an accurate 3D digital environment, which is considered as one of the standard technologies for the next generation of mobile smart products. Limited by the hardware, the dynamic 3D imaging solutions for the mobile terminals are mainly based on Time of Flight (ToF) and structured light techniques. The overall size of ToF can be small, but the measurement accuracy of ToF is not high because of the Multi-Path Interference (MPI) effect. Structured light owns high measurement accuracy, but the accuracy is dependent on the baseline length. In this paper, the plane and spherical surface are measured by ToF and structured light with baseline lengths of 10 cm, 15 cm and 20 cm at a working distance of 0.5 m to 3.0 m, and then the measurement accuracy is calculated and analyzed. The plane measurement errors of the structured light with three different baseline lengths are about 0.15 mm at 0.5 m. Within the working distance, the measurement error of the ToF technique and structured light increases with the increase of working distance. While the measurement accuracy of structured light with three different baseline lengths varies within a small range from 0.5 m to 1.0 m. The measurement accuracy of ToF has exceeded the structured light technique with the baseline length of 10 cm at 3.0 m. In addition, the experiment also tests the influence of reflectivity and MPI effect on the measurement accuracy of ToF. The paper can provide useful reference for the selection and design of dynamic 3D vision sensor in the mobile terminals and guide the design of baseline parameter in the application of structured light module.