Single-Pixel Imaging Based On Photon Count

Single-pixel imaging,a novel computational imaging scheme proposed by researchers in recent years,uses a photodetector with no spatial resolution to acquire images.Compared with an array of photon detectors,single-pixel detectors have a wider spectral response range,higher detection sensitivity,and more accurate temporal resolution.Therefore,single-pixel imaging has unique advantages and is receiving increasing attention in application scenarios such as non-visible wavelength imaging,multispectral imaging,low light level imaging,and threedimensional imaging.This thesis discusses the basic principles of single-pixel imaging and implements photon counting imaging using the time-correlated single photon counting(TCSPC)technique.The contents are as follows:(1)Firstly,the single-pixel imaging principle and TCSPC technology are introduced,focusing on the single-pixel imaging principle based on Hadamard transform and the singlepixel imaging principle based on zero-photon counting,briefly introducing two commonly used single-photon detectors-photomultiplier tube and single-photon counting module,and the TCSPC technology.The basic principles of TCSPC technology are analyzed in detail.(2)A gray single-pixel imaging scheme using a digital micromirror device(DMD)for modulation and TCSPC for photon counting detection is proposed to achieve single-pixel imaging under low light level conditions.The TCSPC technique is used to obtain the statistical histogram of photon arrival time,estimate the measured light intensity.The spatial distribution information of the object is obtained by the Hadamard single-pixel imaging principle,the effects of changing the projection rate and measurement method on the imaging speed and quality are discussed.Finally,the noise immunity of the system is analyzed.(3)A color photon counting single-pixel imaging scheme based gray single-pixel imaging combined with the idea of time-division multiplexing is implemented.This scheme takes full advantage of the time-resolved capability of the TCSPC by using only a single photon detector in a single round of measurements to acquire full-color images in low light level conditions.It also discusses the strategies to improve imaging efficiency through high-speed projection,single-step measurement and under-sampling.(4)A single-pixel imaging scheme based on zero-photon counting under very low light conditions is proposed.This scheme uses zero-photon counting approach to reconstruct the image.The experiments use DMD loaded binary random measurement matrices to modulate the image of the target object,and the modulated laser beam is repeatedly detected for each measurement matrix several times,and the TCSPC gives the number of detected photons.The measurement matrix corresponding to the zero-photon count value is filtered and retained,and the retained measurement matrix is summed to obtain the reconstructed image of the target object.