本文選題：數(shù)字全息 + 微球��； 參考：《北京工業(yè)大學(xué)》2016年碩士論文

【摘要】：數(shù)字全息成像具有實(shí)時、全視場、非接觸和定量相襯成像的優(yōu)勢,在細(xì)胞形貌觀測、微納元件、溫度場、粒子跟蹤等方面,有著廣泛的應(yīng)用前景。隨著生命科學(xué)、微加工技術(shù)、微電子技術(shù)等的飛速發(fā)展,對微小物體三維形貌測量的需求越來越迫切,因此開展超分辨數(shù)字全息成像方法研究具有重要的理論意義和應(yīng)用價(jià)值。目前超分辨率數(shù)字全息成像方法主要包括:空間復(fù)用、亞像素微位移、多光束照明,光柵技術(shù)等技術(shù)。這些方法往往需要記錄多幅全息圖,并需要復(fù)雜的綜合再現(xiàn)算法。研究者通過微球提高成像分辨率。但是,目前僅將微球應(yīng)用到了白光顯微成像系統(tǒng)中,而且只能得到二維成像結(jié)果。本文將微球與數(shù)字全息方法相結(jié)合,將二維成像拓展到高分辨率相襯成像,并進(jìn)一步提高數(shù)字全息技術(shù)的分辨率,主要內(nèi)容如下:研究了微球參數(shù)對微球成像特性的影響。首先,理論推導(dǎo)了微球直徑,折射率等參數(shù)對成像系統(tǒng)球差和數(shù)值孔徑的關(guān)系,研究表明微球的半徑與球差成正比,數(shù)值孔徑先會隨著相對折射率的增大而增大,然后當(dāng)數(shù)值孔徑達(dá)到1后,會隨著相對折射率的增大而減小,當(dāng)半徑和相對折射率適當(dāng)選擇,會得到較高的成像分辨率。然后給出了微球參數(shù)與微球傍軸焦距的關(guān)系式,結(jié)果表明微球傍軸焦距與微球半徑成正比,與微球折射率成反比,并利用COMSOL Multiphysics軟件進(jìn)行仿真驗(yàn)證。最后通過仿真驗(yàn)證了微球具有收集近場倏逝波,并將其轉(zhuǎn)換為遠(yuǎn)場傳輸波的能力。開展了基于微球的高分辨率數(shù)字全息顯微成像研究。分析了微球與顯微物鏡組合的成像理論,并定量分析了微球與顯微物鏡組合以后系統(tǒng)的數(shù)值孔徑。將預(yù)放大超分辨數(shù)字全息顯微成像與微球結(jié)合,搭建了一套基于微球的預(yù)放大像面離軸菲涅耳數(shù)字全息顯微成像系統(tǒng)。然后利用不同尺寸的樣品進(jìn)行實(shí)驗(yàn),驗(yàn)證了微球可以通過一次曝光提高整個視場的橫向分辨率,并通過相位解包裹與曲面擬合的相位畸變處理算法,得到物體相位像。最后進(jìn)行了微球自組裝實(shí)驗(yàn),驗(yàn)證了自組裝可以擴(kuò)大微球成像的視場。
[Abstract]:Digital holographic imaging has the advantages of real-time, full field of view, non-contact and quantitative phase contrast imaging. It has a wide application prospect in cell morphology observation, micro and nano elements, temperature field, particle tracking and so on. With the rapid development of life science, micromachining and microelectronics, it is more and more urgent to measure the three-dimensional morphology of micro-objects. Therefore, the research of super-resolution digital holographic imaging has important theoretical significance and application value. At present, the super-resolution digital holographic imaging methods mainly include: spatial multiplexing, sub-pixel micro-displacement, multi-beam illumination, grating technology and so on. These methods often require multiple holograms to be recorded and complex synthetic reproduction algorithms. Researchers use microspheres to improve imaging resolution. However, only the microspheres are applied to white light microscopic imaging system, and only two-dimensional imaging results can be obtained. In this paper, the microsphere is combined with the digital holography method, and the two-dimensional imaging is extended to the high-resolution phase contrast imaging, and the resolution of the digital holographic technique is further improved. The main contents are as follows: the influence of the parameters of the microsphere on the imaging characteristics of the microsphere is studied. Firstly, the relationship between spherical aberration and numerical aperture of the imaging system is derived theoretically. The results show that the radius of the microsphere is proportional to the spherical aberration, and the numerical aperture increases with the increase of the relative refractive index. Then when the numerical aperture reaches 1, it will decrease with the increase of relative refractive index. When the radius and relative refractive index are properly selected, a higher imaging resolution will be obtained. Then the relationship between the microsphere parameters and the paraxial focal length of the microsphere is given. The results show that the paraxial focal length of the microsphere is proportional to the radius of the microsphere and inversely proportional to the refractive index of the microsphere. The simulation results are verified by COMSOL Multiphysics software. Finally, the capability of collecting near-field evanescent waves and converting them into far-field waves is verified by simulation. The high resolution digital holographic microimaging based on microspheres is studied. The imaging theory of the combination of the microsphere and the microobjective is analyzed, and the numerical aperture of the system after the combination of the microsphere and the microobjective is analyzed quantitatively. An off-axis Fresnel digital holographic imaging system based on microspheres was constructed by combining pre-amplification super-resolution digital holographic imaging with microspheres. Then the experiments with samples of different sizes show that the microsphere can improve the transverse resolution of the whole field of view by one exposure and obtain the phase image of the object by phase unwrapping and phase distortion processing algorithm fitting the curved surface. Finally, the self-assembly experiment is carried out to verify that self-assembly can enlarge the field of view of microsphere imaging.
【學(xué)位授予單位】：北京工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2016
【分類號】：TN26
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本文編號：1988833