Multi frequency long range distance detection for amplitude modulated continuous wave time of flight cameras

Abstract

A time of flight (ToF) system includes a light source, a photosensor, a signal generator and a processor. The signal generator outputs a reference signal corresponding to a modulation function for modulated light and a modified transmitted light signal corresponding to a phase shift of the reference signal. The light source outputs the modified transmitted light signal and pixels in the photosensor receives its reflections off the scene. The reference signal is applied to the pixels and the processor determines a depth map for the scene based on values recorded by the pixels. In some examples, the phase shift is implemented using a phase locked loop controller. One or more component phases of the phase shift and an exposure time for each component phase are determined and output by the phase locked loop controller.