Research On Laser Shadow Photography Testing Technology For Projectile Motion Parameters

High-speed projectile motion parameters are important indicators for measuring the performance of weapons and ammunition,which have always been the focus and difficulty of weapon system testing.Nowadays,the test and measurement system for high-speed projectile motion parameters mostly uses the passive-model laser light source as the illumination system,which not only has low utilization rate for the light source energy,but also has high energy requirements for the light source.In addition,traditional image processing algorithm has great limitations on the identification of target projectiles due to the sensitivities to the surrounding environments.In order to solve these problems,a set of combined-model active laser light source illumination system and a set of target projectile intelligent recognition algorithm based on deep convolutional neural network have been developed and a test verification platform of laser shadow photography test system has also been built in this thesis.The main research contents are as follows:(1)The measurement principles of laser shadow photography test system are expounded;Each module of the system is introduced in detail.A combined-model active laser source illumination system is mainly developed,and the main parameters such as laser pulse width and laser energy are calculated.(2)The high-speed projectile motion parameter solving model is established and the model parameters such as camera internal parameters and coordinate system transformation matrix are calculated by using the camera calibration technology,camera imaging principle and the least squares method.The model parameters were evaluated by mean error which verifies the accuracy of the model parameters.(3)The deep convolutional neural network algorithm is applied to the recognition of target projectiles considering the limitations of traditional image processing algorithm,and then a set of target projectile intelligent recognition algorithm is developed.Through network training and testing,this algorithm achieves recognition accuracy by 99% for the target projectile,and the processing time of an image is about 2s,which fully demonstrates the effectiveness and real-time of this algorithm.(4)The test system test verification platform of the laser shadow photography was built and 20 comparison tests were carried out according to the above study results combined with the solving algorithm of high-speed projectile motion parameter.From the results of the measurement data,we can see that the mean error in the X axial direction is 4.44 mm and in the Z axial direction is 1.94 mm.The measurement error is within an acceptable range,demonstrating that this system can meet the requirements of tests and measurements.