To meet the requirements of a variety of applications, range precision is an important specification for three-dimensional laser radar systems. The proposed laser ranging systems adopt electro-optical modulation and only measures the energy of a laser pulse to obtain range, so that it can reduce many errors in comparison to conventional systems. In this paper, the principle of continuous and pulsed laser ranging systems are introduced, through simulation analysis the target of 20 m, the continuous laser ranging system can achieve a range precision of several centimeters, and the pulsed laser ranging system can achieve a rang precision of several millimeters. And by analyze their advantages and disadvantages, it can be concluded that pulsed laser ranging accuracy is higher than the continuous laser ranging systems. The pulsed laser ranging system is expected to be an alternative method for three-dimensional laser radar system requiring high range precision in many applications.
A dense surface reconstruction approach based on the fusion of monocular vision and three-dimensional (3-D) flash light detection and ranging (LIDAR) is proposed. The texture and geometry information can be obtained simultaneously and quickly for stationary or moving targets with the proposed method. Primarily, our 2-D/3-D fusion imaging system including cameras calibration and an intensity-range image registration algorithm is designed. Subsequently, the adaptive block intensity-range Markov random field (MRF) with optimizing weights is presented to improve the sparse range data from 3-D flash LIDAR. Then the energy function is minimized quickly by conjugate gradient algorithm for each neighborhood system instead of the whole MRF. Finally, the experiments with standard depth datasets and real 2-D/3-D images demonstrate the validity and capability of the proposed scheme.
Silicon photomultiplier (SiPM)-based optoelectronic mixing (OEM) is studied for the first time. The validity of SiPM-based OEM is experimentally verified. Compared with the avalanche photodiodes-based OEM, the SiPM-based OEM is less noisy and easy to realize for its low voltage operation and high responsivity.