Proceedings Article | 12 December 2018
KEYWORDS: Image intensifiers, Signal to noise ratio, Image enhancement, Night vision, Image resolution, Microchannel plates
Since the inception of the first infrared tube, the ability of humans to see objects at night has begun to be met, night vision technology for night observation with photoelectric imaging continues to develop, infrared, low-light night vision technology has emerged one after another, active and passive night vision technology Constantly updated, humans can more and more clearly see the dark night scenery. The core device of night vision technology is like a booster. Its working principle is to first conduct photoelectric conversion, and then use the micro-channel plate to enhance the electronic signal, and finally the electro-optical conversion to achieve the weak light enhancement. The image intensifier itself is a type of device that amplifies weak signals. With the development of science and technology, especially the appearance of microchannel plates, the discovery of negative electron affinity cathodes, and the improvement of optical fiber manufacturing processes, the development of image intensifiers has experienced the first generation of image intensifiers, and the second with microchannel plates. Generation of image intensifiers, third generation image intensifiers using negative electron affinity cathodes, and fourth generation image intensifiers with automatic gated power. At the same time, there are also super second and third generation image intensifiers that are improved on the basis of the second and third generation image intensifiers. The performance of the super-generation image intensifier is not much different from that of the next-generation image intensifier. As far as the development of image intensifiers is concerned, there are many types. How to distinguish the advantages and disadvantages of image intensifiers requires specific parameters. Due to the various aberrations in the electron optical system, the scattering of incident electrons and emitted electrons by the phosphor screen, the limitation of the particle size of the phosphor, and the scattering of light and light from the coupling elements between the stages, the luminance distribution is distorted, and the output is The sharpness of the image drops. Resolution refers to the ability of an imaging device to immediately distinguish the images of two adjacent objects. The detection resolution is the simplest and most commonly used method for assessing the imaging quality of a tube. The method of the resolution of the enhancer resolution is divided into two types according to the resolution determination method: subjective test method and objective test method. With the development of technologies such as digital image processing and computer programming, the objective test method has become increasingly rich in means of implementation, and the test accuracy has been continuously improved. It has become a new research direction for resolution test technology. The noise performance of the image intensifier is a major factor limiting its effective viewing distance and image quality. The presence of background noise can reduce the contrast of the image, affect the sharpness of the image, and even cause the weak image to be overwhelmed and unrecognizable. Therefore, studying the noise characteristics of the LLL enhancer not only helps deepen the understanding of the noise laws in the imaging process, but also provides effective theoretical guidance and technical support for reducing image noise and improving imaging quality, and can further improve the low-light imaging system. The performance to make it work in the best mode. At present, some achievements have been made in the research of low-light image intensifier detection technology. This paper summarizes the previous studies and looks forward to the future development. It is hoped that it can provide some ideas for the further study of image intensifier performance testing technology.
