Modeling And Simulation Of High Dynamic Small Pixel Digital Infrared Detector

With the wide application and development of infrared detector,more and more attention has been paid to the design and development of infrared detector.The new generation of infrared detectors has many innovative technologies and its performance has been greatly improved.The development cycle of infrared detector is long,the cost is high,and the field experiment is complex.Computer simulation can provide parameter optimization guidance,shorten the development cycle and save cost.In order to obtain reliable simulation results,it is very important to establish accurate physical model.Therefore,according to the technical characteristics of the third-generation infrared detector,that is,high dynamic,small pixel,and digital output,a signal-level physical model is established to accurately simulate the imaging process of high dynamic,small pixel,and digital infrared detector.The main research work of this paper is as follows:Firstly,the signal conversion process of infrared detector is analyzed.The influence of dynamic range,pixel size and digital output on infrared detector is studied,and the characteristics of the third generation infrared detector are obtained.According to the related theory of infrared imaging,the imaging process of infrared detector is divided into three parts:photon to electron conversion;electron to voltage conversion;voltage to digital signal conversion.The shortcomings of the existing infrared detector models are discussed.Secondly,the imaging model of signal level is established.According to the imaging process of the detector,the physical mechanism is explained one by one,and the corresponding model is established.According to the three main processes,the whole process of the detector from receiving photons to outputting infrared signal is discussed,which accords with the process of signal flow.The effects of full well charge,pixel size and ADC on the imaging are also considered.Finally,the effects of full well charge,pixel size and digital output on detector imaging are analyzed by simulation.According to the physical model,a digital prototype of high dynamic small image element digital infrared detector is built by using C++.Firstly,by simulating infrared images of different wavebands and different backgrounds,it is concluded that an appropriate full-well charge is essential for the detector to have a clear image.Then through the simulation of changing the pixel size,it is concluded that the smaller the pixel,the higher the resolution of the detector,and under the same instantaneous field of view angle,the optical system with smaller focal length can be used.Finally,through the simulation of the two kinds of structures,the digital detector and the analog output,it is concluded that the digital output can reduce the noise of the infrared detector and provide enough full well charge and reduce the details loss.