Pseudo-Four-Phase-Shift Algorithm for Performance Enhancement of 3D-TOF Vision Systems

Time-of-flight (TOF) sensors have recently become available at reasonable prices. In comparison with stereo vision systems and laser range scanners, they combine the advantages of active sensors, providing accurate distance measurements, and camera-based systems, recording a 2-D matrix at a high frame rate. Moreover, low-cost 3-D imaging has the potential to open a wide field of additional applications and solutions in markets such as consumer electronics, multimedia, digital photography, robotics, and medical technologies. This paper focuses on the currently implemented phase-shift algorithm in this type of sensors. This paper presents a new approach that doubles the frame rate and thereby enhances the performance of photonic mixer device (PMD) TOF sensors. In the experimental section, detailed measurements are presented, and the advantages and disadvantages of the proposed algorithm in comparison with the state-of-the-art algorithm are discussed.