[Paper] A 2-Tap 4-Phase Indirect Time-of-Flight Ranging Method using Half-Pulse Modulation for Depth Precision Enhancement and Sub-Frame Operation for Motion Artifact Suppression

Abstract

In this article, we present a 2-tap indirect time-of-flight (iToF) ranging method using half-pulse (HP) modulation for depth precision enhancement. The operation principle of the ranging method is explained, and theoretical depth noise equations are derived and verified through experiments. Compared to the conventional continuous square-pulse (SP) modulation, the HP modulation exhibited a depth noise reduction of >25% and >29% for the 0.4-3 m range using the HP1 and HP2 methods, respectively. To ensure the depth image quality with moving targets, the motion artifact suppression is demonstrated by applying the sub-frame 4-phase operation. In addition, the application notes and the future directions for utilizing these techniques are discussed.