基于光谱光学相干层析成像的流速测量研究
发布时间：2019-07-09 07:45
【摘要】：光学相干层析成像(Optical Coherence Tomography, OCT)是一门新型的成像技术,具有无辐射、非接触、高探测灵敏度及高分辨率等特点,引起了众多生物医学领域科研工作者的关注。光谱OCT是第二代OCT技术,相比第一代时域OCT技术,它在成像速度、信噪比和灵敏度等方面都具有明显优势,在眼科成像、小动物成像等领域发挥了重要作用,具有广阔的临床和研究前景。首先,介绍光谱OCT成像技术理论。从光和生物组织的相互作用出发,定性解释了光的散射过程。对光谱OCT系统结构进行分析,指出其优越性。阐释OCT成像技术的基本理论,包括低相干干涉理论和共焦显微术理论。在分析光谱OCT信号成分的基础上,指出有效信号项和噪声项。讨论光谱OCT成像系统的主要参数。 其次,搭建快速高分辨光谱OCT成像系统,并进行详细说明。基于2×2光纤耦合器(50/50)对整个系统的干涉光路进行设计。采用2D光学扫描振镜搭建光路扫描系统,此光学扫描振镜由数据采集卡控制。采用超快线阵CCD相机和1145线/mmm光栅对光谱采集系统进行搭建,并通过图像采集卡把采集到的光谱传输给计算机。采用光谱坐标校正法对系统进行色散补偿。指出图像计算的方法,并讨论光源的选择问题。 最后,应用所搭建的光谱OCT成像系统进行相位相关流速测量实验。光谱OCT成像技术与多普勒效应相结合,通过相位差可以求出流动粒子的速度信息。通过理论分析选取匀速横向扫描方式,并对系统的相位稳定性进行评估。分析系统模式噪声和相位噪声的产生机理,并分别采用B扫描平均法和往返程扫描法,成功的消除了系统噪声。针对相位卷绕现象采用相位常数法,消除了此现象,并使流速测量范围扩大了一倍。应用本系统对早期鸡胚胎心脏的血流速度进行活体测量,定量分析了血流分布情况。 综上所述,我们搭建了一套快速高分辨率的光谱OCT成像系统,并应用该系统进行了相位相关流速测量实验。通过本课题的研究实现了成像时间短、分辨率高及测量范围大的光谱OCT成像系统,对临床医学应用起到了推进作用。
文内图片：
图片说明：光谱OCT原理图（BS:BeamSplitter)
[Abstract]:Optical coherence tomography (Optical Coherence Tomography, OCT) is a new imaging technology, which has the characteristics of no radiation, non-contact, high detection sensitivity and high resolution, which has attracted the attention of many researchers in biomedical field. Spectral OCT is the second generation OCT technology. Compared with the first generation time domain OCT technology, it has obvious advantages in imaging speed, signal-to-noise ratio (SNR) and sensitivity. It plays an important role in ophthalmic imaging, small animal imaging and other fields, and has broad clinical and research prospects. Firstly, the theory of spectral OCT imaging technology is introduced. Based on the interaction between light and biological tissue, the scattering process of light is explained qualitatively. The structure of spectral OCT system is analyzed and its advantages are pointed out. The basic theories of OCT imaging technology, including low coherence interference theory and confocal microscopy theory, are explained. On the basis of analyzing the signal components of spectral OCT, the effective signal terms and noise terms are pointed out. The main parameters of spectral OCT imaging system are discussed. Secondly, a fast high resolution spectral OCT imaging system is built and described in detail. The interference optical path of the whole system is designed based on 2 脳 2 fiber couplers (50 脳 50). The optical path scanning system is constructed by using 2D optical scanning mirror, which is controlled by data acquisition card. The spectral acquisition system is built by using ultra-fast linear CCD camera and 1145 line / mmm grating, and the collected spectrum is transmitted to the computer through the image acquisition card. The spectral coordinate correction method is used to compensate the dispersion of the system. The method of image calculation is pointed out, and the selection of light source is discussed. Finally, the phase correlation velocity measurement experiment is carried out by using the spectral OCT imaging system. Combining spectral OCT imaging with Doppler effect, the velocity information of flow particles can be obtained by phase difference. Through theoretical analysis, the uniform transverse scanning mode is selected, and the phase stability of the system is evaluated. The generation mechanism of mode noise and phase noise of the system is analyzed, and the B scan average method and the round trip scanning method are used to eliminate the system noise successfully. The phase constant method is used to eliminate this phenomenon and double the range of velocity measurement. The blood flow velocity of early chicken embryo heart was measured in vivo by this system, and the blood flow distribution was analyzed quantitatively. To sum up, we built a set of fast and high-resolution spectral OCT imaging system, and used the system to measure the phase-dependent velocity. Through the research of this subject, a spectral OCT imaging system with short imaging time, high resolution and wide measurement range is realized, which plays an important role in clinical medical application.
【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R310;O433
本文编号：2511987
文内图片：
图片说明：光谱OCT原理图（BS:BeamSplitter)
[Abstract]:Optical coherence tomography (Optical Coherence Tomography, OCT) is a new imaging technology, which has the characteristics of no radiation, non-contact, high detection sensitivity and high resolution, which has attracted the attention of many researchers in biomedical field. Spectral OCT is the second generation OCT technology. Compared with the first generation time domain OCT technology, it has obvious advantages in imaging speed, signal-to-noise ratio (SNR) and sensitivity. It plays an important role in ophthalmic imaging, small animal imaging and other fields, and has broad clinical and research prospects. Firstly, the theory of spectral OCT imaging technology is introduced. Based on the interaction between light and biological tissue, the scattering process of light is explained qualitatively. The structure of spectral OCT system is analyzed and its advantages are pointed out. The basic theories of OCT imaging technology, including low coherence interference theory and confocal microscopy theory, are explained. On the basis of analyzing the signal components of spectral OCT, the effective signal terms and noise terms are pointed out. The main parameters of spectral OCT imaging system are discussed. Secondly, a fast high resolution spectral OCT imaging system is built and described in detail. The interference optical path of the whole system is designed based on 2 脳 2 fiber couplers (50 脳 50). The optical path scanning system is constructed by using 2D optical scanning mirror, which is controlled by data acquisition card. The spectral acquisition system is built by using ultra-fast linear CCD camera and 1145 line / mmm grating, and the collected spectrum is transmitted to the computer through the image acquisition card. The spectral coordinate correction method is used to compensate the dispersion of the system. The method of image calculation is pointed out, and the selection of light source is discussed. Finally, the phase correlation velocity measurement experiment is carried out by using the spectral OCT imaging system. Combining spectral OCT imaging with Doppler effect, the velocity information of flow particles can be obtained by phase difference. Through theoretical analysis, the uniform transverse scanning mode is selected, and the phase stability of the system is evaluated. The generation mechanism of mode noise and phase noise of the system is analyzed, and the B scan average method and the round trip scanning method are used to eliminate the system noise successfully. The phase constant method is used to eliminate this phenomenon and double the range of velocity measurement. The blood flow velocity of early chicken embryo heart was measured in vivo by this system, and the blood flow distribution was analyzed quantitatively. To sum up, we built a set of fast and high-resolution spectral OCT imaging system, and used the system to measure the phase-dependent velocity. Through the research of this subject, a spectral OCT imaging system with short imaging time, high resolution and wide measurement range is realized, which plays an important role in clinical medical application.
【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R310;O433
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