Key Laboratory of Electronic Testing Technology for National Defense Science and Technology, North University of China, Taiyuan 030000, China.
Experimental Testing Institute, China North Industries Group Corporation Limited, Weinan 714000, China.
Sensors (Basel). 2020 Jan 19;20(2):554. doi: 10.3390/s20020554.
In the laser screen velocity measuring (LSVM) system, there is a deviation in the consistency of the optoelectronic response between the start light screen and the stop light screen. When the projectile passes through the light screen, the projectile's over-target position, at which the timing pulse of the LSVM system is triggered, deviates from the actual position of the light screen (i.e., the target deviation). Therefore, it brings errors to the measurement of the projectile's velocity, which has become a bottleneck, affecting the construction of a higher precision optoelectronic velocity measuring system. To solve this problem, this paper proposes a method based on high-speed shadow imaging to measure the projectile's target deviation, ΔS, when the LSVM system triggers the timing pulse. The infrared pulse laser is collimated by the combination of the aspherical lens to form a parallel laser source that is used as the light source of the system. When the projectile passes through the light screen, the projectile's over-target signal is processed by the specially designed trigger circuit. It uses the rising and falling edges of this signal to trigger the camera and pulsed laser source, respectively, to ensure that the projectile's over-target image is adequately exposed. By capturing the images of the light screen of the LSVM system and the over-target projectile separately, this method of image edge detection was used to calculate the target deviation, and this value was used to correct the target distance of the LSVM to improve the accuracy of the measurement of the projectile's velocity.
在激光光幕测速（LSVM）系统中，起始光幕和停止光幕的光电响应一致性存在偏差。当弹丸穿过光幕时，触发 LSVM 系统定时脉冲的弹丸过靶位置会偏离光靶的实际位置（即靶偏），从而给弹丸速度测量带来误差，成为制约高精度光电测速系统构建的瓶颈。针对这一问题，本文提出了一种基于高速阴影成像的方法，用于测量 LSVM 系统触发定时脉冲时的弹丸靶偏ΔS。采用非球面透镜组合对红外脉冲激光进行准直，形成平行激光源作为系统的光源。当弹丸穿过光幕时，弹丸过靶信号由专门设计的触发电路进行处理，利用该信号的上升沿和下降沿分别触发相机和脉冲激光源，以保证弹丸过靶图像得到充分曝光。通过分别拍摄 LSVM 系统光靶和过靶弹丸的图像，采用图像边缘检测方法计算靶偏，并用该值修正 LSVM 的靶距，提高弹丸速度测量精度。
