基于无透镜数字全息的微颗粒成像系统设计

发布时间：2018-04-28 00:00

本文选题：压载水 + 微藻　；参考：《大连海事大学》2017年硕士论文

【摘要】：随着我国航运事业的发展,船舶压载水中微生物跨区域传播的危害问题也越来越严重,因此对海洋中的微藻进行成像与检测具有重要的意义。传统的成像及检测设备存在体积大、价格昂贵、需要较高的操作水平、无法进行现场检测等缺点。为了实现压载水中微藻的成像与检测,本文设计了一种同轴无透镜数字全息微颗粒成像系统。该系统实现了微颗粒的成像,获得了微颗粒的三维形貌及三维尺寸,并通过对海水中扁藻的成像证明了该系统可用于海洋微藻的成像及活性检测。本文的主要工作有:(1)从标量衍射理论出发分析了同轴无透镜数字全息微颗粒成像系统中光源波长、小孔直径、光源到样品的距离以及样品的记录距离等参数,推导了各参数之间的关系。在设计同轴无透镜数字全息成像系统时,可按照它们之间的关系得出成像系统各部分的最佳搭配。(2)设计了同轴无透镜数字全息微颗粒成像系统。该系统利用部分相干光源LED作为全息干涉的光源,通过耦合小孔增加部分相干光源的相干性,以盖玻片为平台,利用去除透镜的CMOS图像传感器获得了微颗粒的同轴全息图。(3)对比分析了菲涅尔积分变换、菲涅尔卷积及角谱重建算法,得到了不同重建算法的适用范围,并推导了利用角谱重建算法时的再现距离的计算公式。(4)利用共轭像消除算法获得了消除了共轭实像的同轴全息再现像,并利用解包裹算法获得了微颗粒的真实相位,重建了微颗粒的三维形貌并获得了微颗粒三维尺寸。(5)拍摄了海水中扁藻的全息图,重建了扁藻的再现像,消除了扁藻再现像的共轭像,并恢复了扁藻的三维形貌。最后将扁藻的相位信息与显微镜下的扁藻图像作对比,对扁藻的活性进行了判断,证明了该系统不仅可以获得微藻的三维信息,也可以用于海洋中微藻活性的检测。
[Abstract]:With the development of shipping industry in China, the problem of transregional spread of microorganism in ship ballast water is becoming more and more serious, so it is of great significance to image and detect microalgae in the ocean. The traditional imaging and detection equipment has the disadvantages of large volume, high price, high level of operation, unable to carry out field inspection and so on. In order to realize the imaging and detection of microalgae in ballast water, a coaxial lensless digital holographic microparticle imaging system is designed in this paper. The system has realized the imaging of microparticles, obtained the three-dimensional morphology and size of microparticles, and proved that the system can be used for the imaging and activity detection of marine microalgae by imaging the algae in seawater. Based on the scalar diffraction theory, the parameters such as the wavelength of the light source, the diameter of the aperture, the distance from the light source to the sample and the recording distance of the sample in the digital holographic microparticle imaging system with coaxial lens are analyzed. The relationship between the parameters is deduced. In the design of the coaxial lensless digital holographic imaging system, according to the relationship between them, the optimum collocation of each part of the imaging system can be obtained. (2) the coaxial lensless digital holographic microparticle imaging system is designed. In this system, the partially coherent light source (LED) is used as the light source for holographic interference, and the coherence of the partially coherent light source is increased through the coupling holes, and the cover glass is used as the platform. The coaxial holograms of microparticles are obtained by using the CMOS image sensor which removes the lens. The Fresnel integral transform, Fresnel convolution and angular spectrum reconstruction algorithms are compared and analyzed, and the applicable range of the different reconstruction algorithms is obtained. The formula for calculating the reconstruction distance of the angular spectrum reconstruction algorithm is derived. The conjugate image elimination algorithm is used to obtain the coaxial holographic reconstruction image which eliminates the conjugate real image, and the real phase of the microparticle is obtained by unwrapping algorithm. The three-dimensional morphology of the microparticle was reconstructed and the three-dimensional size of the microparticle was obtained. The hologram of the alga in seawater was taken, the reconstructed image of the alga was reconstructed, the conjugate image of the reconstructed image of the alga was eliminated, and the three-dimensional morphology of the alga was restored. Finally, the phase information of the alga is compared with the microalgae image under the microscope, and the activity of the alga is judged. It is proved that the system can not only obtain the three-dimensional information of the microalgae, but also can be used to detect the activity of the microalgae in the ocean.
【学位授予单位】：大连海事大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP391.41

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