Research On Key Technology Of Close Measurement For Small, Dark, Rapid, And Multi Targets

With the rapid development of weapons systems, new requirements are raisedfor measurement of small, dark, rapid, multi targets in modern shooting ranges.Since the rapid, multi targets are smalland non-luminous, to get clear pictures of thetargets, corresponding optical measurement equipment must have the characteristicsof high frame rate, high sensitivity and large field of view. For reasons of safety andcost, optical measurement equipments are posited far from the targets, thereforedetails of the targets movement are missed. Based on modern electroniccommunication technology and camera measurement technique, image acquisitionand storage, camera calibration and targets measurement are taken into considerationthis problem in this dissertation. The main works are summed in follows:(1) A new low-cost high speed camera is designed with the consideration ofmeasurement requirements and hardware costs. The image resolution is2Kx1K andthe maximum frame frequency is up to280fps under the condition of full resolution.Exposure of the camera can adjust to application environment. The key technologiesof camera design are explained in details, especially for bit alignment and wordalignment technique in the process of high-speed data acquisition. Under theminiaturization of the measuring device, trend of better portability and low powerconsumption, an embedded image storage system is also designed with thehigh-speed SATA interface. The experimental results indicate that the bandwidth of storage system can reach294MB/s。(2) In this paper, the camera calibration technology is in-depth researched. Theexternal and internal parameters of camera are estimated using the plane calibrationalgorithm with planar checkerboard. The plane calibration algorithm is easy andflexible, but sometimes the algorithm is not convergent in practice when the numberof calibration imagesis more than10. A modified method is proposed to ensurecalibration convergence. The modified method divides the calibration images intocorrect images and false images using Random Sample Consensus（RANSAC）algorithm, and calibrates camera only for good images. The experimental resultsshow that the robust modified method can reduce the number of iteration, andcalibration precision increase by35%.(3) To satisfy actual demand for the measurement of small, dark, rapid, multitargets, planar imaging measurement, easy and high flexibly, is used to monocularmeasure the miss distance and drop point coordinates of targets in this paper. On thisbasis, nature of the projective geometry of parabola is proved and a novel monocularmeasurement method is proposed for parabolic motion of point targets. Bothcomputer simulation and real data have been used to verify the feasibility of thismethod.. Practical globule throwing experiments show that the measurement erroris less than1.2%compared with binocular measurement methods.(4) For general measurement tasks, the key technologies for intersectionmeasuring are firstly introduced, which include3D European reconstruction, stereomatching and external parameters calibration, etc. Secondly, the influence ofexternal structure parameters on the accuracy of measurement is analyzedemphatically, and the optimal parameters are achieved by numerical simulation.Finally, Aiming at measurement of the small, dark, rapid, multi targets drop point, anovel plane intersection method is raised and it can be applied in large view field,long distance and coarse measurement occasions.