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

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.