Illumination, phase step optimization and improvements in simultaneous multiple frequency measurement for Time-of-Flight sensors

The systematic linearity error due to harmonics present in a Time-of-Flight (TOF) sensor system contributes to the inaccuracy of its three dimensional (3D) depth measurements. In this paper, a modified method which combines illumination waveform optimization and phase stepping algorithm selection is proposed to achieve a better performance at measurement linearity through numerical and practical experiment. Additionally, a solution of high-order harmonic reduction in simultaneous multiple frequency framework is investigated for unambiguous range and acceptable high frame rate.