Research Of Two-dimensional Laser Displacement Sensor Based On FPGA

The two-dimensional laser displacement sensor, based on line structured lightmeasurement principle, is a sophisticated fast measuring device of two-dimensionalcontour. Compared with conventional displacement sensors,it has the advantages ofsimpler structure, smaller size, higher speed, higher efficiency, etc. Based on thestudys on line structured light principle and hardware image processing algorithms,this paper accomplished the research on design of FPGA-based two-dimensionallaser displacement sensor,which meets the industrialized sensor miniaturizationtrend. The main work is as follows:1) A mathematical model of two-dimensional laser displacement sensor isestablished on the basis of the basic theoretical study of line structured light. Andthe overall hardware design structure based on FPGA processor, camera-linkinterface camera and line laser is defined.2) A hardware circuit design of image acquisition and data processing iscompleted with field programmable logic devices being its core. It mainly consistsof the following circuits:interface circuit of Camera link, control circuit based onFPGA chip EP3C40Q240C8, the data storage circuit, VGA display interface circuitand the serial communication interface circuit.3) Referring to the the basic design ideas of sequential circuit,the driver logicfor system hardware platform is developed with the Verilog language. It mainlyincludes the following modules: data acquisition module, asynchronous FIFOmodule, SDRAM controller module, VGA display interface module andasynchronous serial communication module.4) Based on the Gaussian beam characteristics of the flat section of line laseroptical projection, a research on light strip center location algorithm based ongradient centroid and grayscale centroid is done, combining with the characteristicsof the FPGA hardware algorithms. And accuracy analysis and comparison of the twoalgorithms are provided.5) System calibration is accomplished using free two-dimensional calibrationtarget. A precision analysis on the system is also given.