Emccd Photon Imaging Systems

Photon counting imaging is an effective means of detecting very low light, and is one kind of imaging technology which combines ultra-high sensitivity optical sensors and signal processing.EMCCD has the function of charge multiplication which is more than the usual CCD.With the capability of photon detection, EMCCD is one of the possible ways to realize photon counting imaging.The EMCCD-based photon counting imaging system is discussed in this article from following aspects.First, gain statistical model of the EMCCD working in the high-gain mode is presented in this paper. The probability density function of the gain of EMCCD is simulated.The experiment of actual gain of the EMCCD is designed,described and analyzed.Through the research of the EMCCD multiplication model working in the high gain mode, the problem of EMCCD realizing photon counting imaging is solved.Second, the performance parameters based on EMCCD photon imaging system is studied in this paper. The parameters including dark current noise, induced clock noise, readout noise, conversion gain,full well charge capacity is discussed. The attenuation and illumination curve, illumination and output signal curve, photon transfer curve are obtained by testing, and the number of the photons per pixel is calibrated.The test of performance parameters of EMCCD photon counting imaging system lays the foundation for the EMCCD in photon counting imaging technology, and provides a reliable standard of parameters.Third, the experiment based on the EMCCD photon counting imaging is designed in this paper. A new image processing algorithm-photon threshold extraction which has resolved the technical problems of extracting information of the image from the background with noise is proposed.Photon threshold extraction is a method of image denoising, background correction, image smoothing, image sharpening, pieces of cumulative, amplitude threshold filtering.and frequency threshold filtering.With the further development of Night Vision technology, the photon detection technology will replace the traditional low light imaging.