| 题名 | 傅里叶叠层显微成像中的成像性能优化方法研究 |
| 作者 | 周奥 |
| 文献子类 | 硕士 |
| 导师 | 司徒国海 |
| 关键词 | 相位恢复 Phase retrieval 显微 Microscopy 计算成像 Computational imaging 图像重建 Image reconstruction |
| 其他题名 | Optimization for image enhancement in Fourier ptychographic microscopy |
| 英文摘要 | 傅里叶叠层显微是近年来发展出的一种新的计算成像技术，该技术的提出，打破了传统显微镜成像分辨率和视场之间的矛盾，可实现高分辨率、大视场显微成像。此外，傅里叶叠层显微技术本质上是一种相位恢复技术，通过对在不同角度平行光照明下得到的多幅样本强度图进行迭代运算，可以量化相位成像，这意味着该技术可以用来观察透明样本。傅里叶叠层显微技术具有的独特优势，使其在生物医疗领域有很大的潜在应用价值。 尽管傅里叶叠层显微成像技术拥有许多优势，但也存在数据采集时间长、物镜成像边缘区域波像差较大、LED位置不精确带来累计误差等缺点，这些缺点阻碍了傅里叶叠层显微技术进一步的应用。本文针对傅里叶叠层显微成像中存在的缺点，对傅里叶叠层显微成像过程中涉及的LED位置校正和数据采集两方面问题进行了研究，所取得的主要成果如下： 1、针对纯振幅型样本，提出一种可以减少数据采集量的方法。通过理论计算和仿真分析得到，当样本为纯振幅类型时，位置呈圆对称的两LED分别照明样本得到的图片强度相同。在此理论基础之上，结合傅里叶叠层显微成像仅使用样本强度图像进行重建的特点，仿真和实验表明，利用一半图片重建得到的结果与使用全部图片相比，分辨率无明显变化。该方法与其他方法相结合，可将数据量减少到四分之一。 2、提出了一种LED阵列全局水平偏移量的校正方法。该方法通过简化LED阵列位置失配模型参数，结合傅里叶叠层显微重建算法，采用模拟退火算法直接对LED阵列两水平偏移量进行校正。与传统方法采用模拟退火算法在频域对光瞳函数中心位置校正进而消除LED位置偏移相比，我们提出的方法更加快速有效。; Fourier ptychographic microscopy (FPM) is a newly developed computational imaging technique in recent years. FPM breaks the trade-off between the resolution and the field of view of the standard microscope. In addition, FPM is a phase retrieval technique and can achieve quantitative phase imaging by iteratively computing multiple sample intensity images obtained under sequential illumination of LEDs from different angles. This means that it can be used to observe phase-contrast samples. These unique advantages offer potential for FPM to apply in many fields, such as biomedicine. However, FPM is also encountered some problems, such as the long data acquisition time, and inaccurate estimation of the LEDs’ positions. These disadvantages impede the application of FPM. This thesis aims at solving the aforementioned problems, and achieves the following main results: 1. We proposed a method to reduce the number of captured images for the FPM reconstruction of amplitude-only samples. By theoretical calculation and simulation analysis, we find that the captured images with circular symmetrical illumination angles have no intensity difference when the object is amplitude-only. Based on this theory, combined with the fact that FPM only uses sample intensity images for reconstruction, simulations and experiments show that the reconstruction results obtained with half of the sample images have no significant change in resolution compared with using all images. Combined with other methods, the number of the captured image can be reduced to 25%. 2. We proposed a global shift correction method for LED arrays. We simplify the LED array position misalignment model with only global horizontal shifts. The proposed method modifies the two horizontal shifts of the LED array directly by using the simulated annealing algorithm. Compared with the traditional method of using the simulated annealing algorithm to correct the center position of the pupil function in the Fourier domain, the proposed method is more rapid and effective. |
| 学科主题 | 光学工程 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/31107]  |
| 专题 | 中国科学院上海光学精密机械研究所 |
| 作者单位 | 中国科学院上海光学精密机械研究所 |
| 推荐引用方式 GB/T 7714 | 周奥. 傅里叶叠层显微成像中的成像性能优化方法研究[D]. |
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