Research On 3D Coordinate Measurement Technology For Spatial Points Based On PSD

Spatial 3D coordinate measurement technology has been widely used in advanced manufacturing,robot navigation,spacecraft rendezvous and docking,missile tracking and positioning and medical service.With the rapid development of optoelectronic semiconductor devices,the use of photodetection technology to obtain 3D coordinates of a target has become a research hotspot in the current measurement field.Position Sensitive Detector(PSD)is a continuous photoelectric device based on lateral photoelectric effect and sensitive to incident light.It has such advantages as continuous measurement,fast response,high position resolution,relatively simple signal processing circuit and low requirement on optical system.But at present,there is less research on 3D coordinate measurement system based on PSD.Therefore,according to the principle of binocular vision,this paper builds a 3D coordinate measurement system based on PSD to realize 3D coordinate measurement of the red LED point light source placed on the target.The main research work of this paper is as follows:Firstly,the working principle and performance index of PSD are described,the 3D coordinate measurement hardware system for spatial points based on PSD is built,and the data acquisition and storage program is written based on LabVIEW platform.Secondly,BP neural network is applied to 3D coordinate measurement for spatial points based on PSD.The 3D coordinate measurement prediction for spatial points based on BP neural network is realized by writing MATLAB program,and the measurement error between the actual position coordinates of spatial points and the predicted coordinates of BP neural network is calculated.Then,aiming at the shortcomings of BP neural network algorithm in spatial 3D coordinate measurement,BP neural network is optimized by genetic algorithm and mind evolutionary algorithm respectively.Results show that BP neural network optimized by mind evolutionary algorithm has higher accuracy in 3D coordinate measurement.Finally,various factors affecting the error of 3D coordinate measurement system based on PSD are analyzed and measures to reduce the error are put forward.Through experiments,the influence of background light on 3D coordinate measurement accuracy is quantitatively analyzed.