Study On Measurement Method Of Optical Field Imaging Fragment Dispersion

In the field of weapon shooting range testing,the dispersion position of fragments after projectile near explosion is not only an important parameter for fragment damage efficiency evaluation,but also a key index to measure the performance of ammunition.Due to the randomness and uncertainty of fragment scattering position,especially when multiple fragments reach a certain position at the same time,there is a shielding phenomenon between each other,which makes it difficult for the existing test methods to obtain the position of each fragment,which brings some difficulties to the fragment position test.Aiming at the problem of position measurement and solution under the mutual occlusion of fragments,a method of position measurement of light field imaging fragments is studied in this thesis.Based on the research status of fragment position measurement methods at home and abroad,a fragment position measurement method of dual light field intersection imaging is proposed in this thesis.A fragment position test system for dual field intersection imaging is designed.The working principle of the test system and the overall architecture of fragment position solution are given.Based on the imaging principle of microlens array,combined with the geometric relationship of two light field cameras and the four-dimensional ray information of fragments,an analytical model for the location test of fragments in the intersection imaging of two light fields is established,the analytical function of the location of fragments in the case of mutual occlusion is given,and the error of the analytical model is modeled and simulated.According to the correlation of the imaging information of fragments in two light field cameras,the fragment position recognition model and the polar constraint model of the refocusing plane are constructed respectively.Based on the Bayesian decision principle,the fragment matching combination decision function is obtained,and the real combination sequence of fragment image points to be matched is screened.In order to improve the accuracy of fragment position measurement,the effects of non coplanar optical axis and heavy fragment image point offset of two light field cameras on fragment position measurement results are studied.The effects of structural parameters of the test model on measurement uncertainty and test target surface are discussed respectively,and a reasonable station layout method is determined.According to the established analytical model of fragment location test for dual light field intersection imaging,the corresponding experiments are designed,and the experimental test platform is built.At the same time,the fragment location of wood target is added as the comparative verification.The experimental results show that the method proposed in this thesis can effectively solve the location test under the mutual occlusion of fragments and calculate the spatial location parameters of fragments.Compared with the fragment position coordinates measured by the wood target,the test results meet the requirements,which verifies the correctness and feasibility of the proposed method for measuring the fragment position of dual light field intersection imaging,and has certain theoretical guidance and practical application value.