Understanding and ameliorating mixed pixels and multipath interference in AMCW lidar

Abstract

Amplitude modulated continuous wave (AMCW) lidar systems suffer from significant systematic errors due to mixed pixels and multipath interference. Commercial systems can achieve centimetre precision, however accuracy is typically an order of magnitude worse limiting practical use of these devices. In this chapter the authors address AMCW measurement formation and the causes of mixed pixels and multipath interference. A comprehensive review of the literature is given, from the first reports of mixed pixels in point-scanning AMCW systems, through to the gamut of research over the past two decades into mixed pixels and multipath interference. An overview of a variety of detection and mitigation techniques, including deconvolution based intra-camera scattering reduction, modelling of intra-scene scattering, correlation waveform deconvolution techniques/multifrequency sampling and standard removal approaches, all of which can be applied to range-data from standard commercial cameras is presented. The chapter concludes with comments on future work for better detection and correction of systematic errors in full-field AMCW lidar.