Application Of Single-pixel Camera In Scattering Media Imaging

The existence of scattering medium deteriorates the quality of imaging, and even makes the imaging impossible. Therefore, the research on imaging through scattering media is of significant. Compared with the traditional imaging system, single-pixel camera is a new imaging system with the characters of low cost, simple system and wide range of applications. The single-pixel imaging system only needs to detect the light intensity changes when it loads different masks. This thesis focuses on single-pixel imaging in scattering medium based on the characteristics of single-pixel imaging system. Experimental feasibility is verified through theoretical analysis and simulation. An experiment system is set up to realize the scattering medium imaging. This thesis focuses on the research from the following aspects:(1) Digital micro mirror is the core component for single-pixel imaging. The characteristics, the parameters, machining process and working principle of the digital micro mirror device are introduced. Its advantages and disadvantages of the single-pixel imaging device are given by comparison with the similar devices.(2)Two representative methods in the single-pixel imaging, compressed sensing theory and four-step phase-shifting theory are introduced. As a classic theory in the single-pixel imaging, the thesis introduces compressed sensing theory through three aspects: the single-pixel imaging’s measurement Matrix, transmission matrix and reconstruction algorithm. The suitable matrixes for digital micro mirror applications are also introduced. Besides, a new type of four-step phase-shifting method is introduced, including its image-forming principle features and reconstructing algorithm.(3) The feasibility of single-pixel imaging is proved through simulation and experiment. Single pixel imaging through a single layer scattering medium is successfully realized by using of the feature of single-pixel imaging system needing only to detect the light intensity changes when different masks are loaded. The scattering characteristics of scattering medium are analyzed. By using the memory effect of the scattering medium and combining the four-step phase-shifting theory, a single pixel imaging system is designed and applied to imaging objects in a double layer scattering media. This system is simple and without the need of complicated time gating and other devices so that it effectively reduces the cost of the experiment. It also can distinguish ballistic photons and serpentine photons. The feasibility of the system in the double layer scattering medium imaging is proved. The noise in the experiment is analyzed and a method to improve the imaging quality of the system is given.