微光像增强器光晕消失时间测试方法

Test method for halo disappearance time of low-level-light image intensifier

  • 摘要: 光晕(halo)效应对微光像增强器探测的应用造成了不利影响且不可避免。微光像增强器的光晕消失时间缺乏测试方法,因此提出了基于数字目视的光晕消失时间测试系统。该系统通过开关电源给LED光源提供频率为25 Hz、占空比可调的脉冲信号,利用高帧率相机连续采集1 500张像增强器经直径为3.5 mm小孔后的图像,其中包含若干个完整的明暗周期。通过重复计算标准差,去除偏离平均值的周期序列来优化周期信息,获得亮暗周期内光源熄灭的图片索引,同理可获得光晕消失的图片数量,从而计算得到光晕消失时间。编号为GZ318118A的像增强器光晕消失时间为3.33 ms。测试结果表明,测量装置的重复性为0.863%,可以对光晕消失时间进行有效测试。

     

    Abstract: The halo effect has a negative impact on the application of detection of low-level-light image intensifier, and it is unavoidable. The method for testing the halo disappearance time of low-level-light image intensifier is lacking. To address this, a halo disappearance time test system based on digital vision was proposed. The system provided a pulse signal with a frequency of 25 Hz and an adjustable duty cycle to the LED light source through a switching power supply. 1 500 images of the image intensifier passing through a small hole with a diameter of 3.5 mm were captured by a high frame rate camera, including several complete light and dark cycles. The period information was optimized by repeatedly calculating the standard deviation to remove the periodic sequence that deviated from the average value, and the image index where the light source was turned off in the light and dark period was obtained. Similarly, the number of pictures where the halo disappeared could be obtained, thereby calculating the disappearance time of the halo. The halo disappearance time of image intensifier is 3.33 ms with the serial number GZ318118A. The test results show that the repeatability of the measuring device is 0.863%, which can effectively test the disappearance time of the halo.

     

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