基于变焦透镜的光片显微三维成像研究

With the development of life science, the optical sectioning fluorescence micrographic imaging technique is always challenged. Aimed at the need of real-time bio-detection for thick biological samples, the research of optical sectioning fluorescence micrographic three dimensional imaging based on electrically-addressable liquid variable focus lens has been developed. Based on the merit function constructed by the modulation transfer function difference between of initial and arbitrary position, the dynamic model of variable focus lens has been established. It is used to optimize the aberration and dynamic characteristics of liquid variable focus lens. And the optical sectioning micrographic imaging system model has been established based on liquid variable focus lens. The influence of variable focus lens on point spread function and magnification has also been studied. In addition, the scanning method of matching illumination optical sheet and focused object plane has been proposed to improve the speed of capturing images. The work of studying the interaction mechanism of axial scanning range, resolution, scanning speed and signal to noise ratio has been carried out. According to multi-resolution analyzing, the image fusion algorithm such as pyramid transform, wavelet transform and neural network has been put forward to realize the fusion and construction of a stack of depth images. At the same time, the optimal three dimensional optical sectioning fluorescence micrographic imaging system based on variable focus lens has been set up. The biological sample with the millimeter scale thickness and capturing images speed of more than 100Hz could be captured in real time. The main advantage of our project is the possibility of avoiding the axial scanning and decreasing the optical damage of samples. It will provide the important detection method and tool for thick biological samples and promote the development of life science greatly.

生命科学的发展不断对光学荧光显微成像技术提出挑战，针对厚生物样品的活体实时检测需求，开展基于电控变焦液态透镜的光片荧光显微三维成像研究。以透镜初始和任意变焦时的调制传递函数差值构造评价函数，建立变焦透镜动态模型，优化其像差和动态特性。建立基于变焦透镜的光片显微成像系统模型，研究变焦透镜对系统点扩散函数和放大倍率等参数影响，优化光学系统参数。提出照明光片和聚焦成像物面的匹配扫描方法，提高图像获取速度。研究轴向扫描范围、分辨率、扫描速度和信噪比相互作用机理；研究基于多分辨率分析的金字塔变换、小波变换和神经网络等的图像融合算法，解决多幅有噪图像的融合和重建。搭建最优化的基于变焦透镜的光片荧光显微三维成像系统，实现测量速度大于100Hz的毫米量级厚度生物样品活体实时检测实验。本项目测量方法和系统避免了样品轴向移动，降低了样品光损伤，为厚生物样品提供了重要的检测方法和工具，可促进生命科学的发展。

为满足厚生物样品的活体实时检测需求，本项目提出一种基于变焦液体透镜的光片荧光三维显微成像系统，将液体变焦透镜置于双远心成像光路中，在成像过程中系统放大率保持不变。建立了基于液体变焦透镜的光片荧光显微成像系统模型，利用光线追迹方法，分析了变焦透镜的口径、光焦度和像差对系统的影响。针对光片荧光显微成像系统所需的大口径和大调谐范围的液体变焦透镜，研究了5种液体变焦透镜。降低电极宽度/间隔比、增加电极厚度可以提高液晶透镜的焦距调谐范围，降低其门槛驱动电压。建立了电润湿变焦透镜模型，获取了半月板面型方程。分析了透镜焦距、波像差与口径、外加电压的关系，发现液体变焦透镜焦距取决于接触角，且随着口径的增加，焦距调谐范围变小；且像差值和焦距值成反比。建立了两液体变焦透镜组合的透镜系统，其具有两个可独立调谐的半月板，可扩展液体变焦透镜的焦距调谐范围。提出了三相接触点处切线角和接触角多因素作用于半月板的单液体变焦透镜，包含球形凝胶-液体和非球形液体-空气界面，突破了传统的液体透镜的焦距调谐范围受接触角饱和的限制，进一步提高了液体的焦距调谐范围。提出了电荷极化作用驱动的双液体变焦透镜，在外加电压作用下，凝胶中的电子发生极化作用，产生麦克斯韦力，引起凝胶的非对称性变形，使得透镜的门槛驱动电压降低。搭建了基于液体变焦透镜的光片荧光显微成像系统，并对物面的轴向扫描范围、分辨率、景深、放大率和光片尺寸等参数进行了测量，并对与癌细胞大小相当的荧光微球进行了成像测试，获得了样品的三维形貌。已发表4篇论文（2篇二区，1篇三区），2篇论文审稿中，2篇论文撰写中，申请中国发明专利5项，培养3名硕士生和1名博士生。获批了中英合作和交流项目“基于变焦液体透镜的超快单像素数据压缩光学成像研究”。本项目测量方法和系统避免了样品轴向移动，降低了样品光损伤，将液体透镜和基于液体透镜的光片显微成像系统仪器化，项目具有很好的应用前景。