上海理工大学 教育部现代微创医疗器械及技术工程研究中心 生物医学光学与视光学研究所， 上海 200093
散斑存在于光学相干层析成像(OCT)信号中，不可避免地影响OCT图像质量。通过对OCT系统中的噪声源进行分析，提出了一种傅里叶域OCT图像散斑噪声降噪的分数阶积分算法。为了克服单纯主观视觉判别图像质量的局限性，均方误差、峰值信号噪声比和边缘保护系数被选为图像去噪评估标准。通过实验与中值滤波和维纳滤波方法进行比较，结果表明，该算法可以有效地保留OCT图像中的重要边缘细节信息，同时有效消除噪声，使图像细节清晰，提高图像质量。
光学相干层析成像 散斑噪声 图像去噪 分数阶积分算法 optical coherence tomography speckle noise image denoising fractional integral algorithm
Author Affiliations
Abstract
1 Institute of Biomedical Optics and Optometry, Shanghai Institute for Minimally Invasive Therapy, University of Shanghai for Science and Technology, Shanghai 200093, China
2 Beckman Laser Institute and Center for Biomedical Engineering, University of California, Irvine, CA 92612, USA
3 Systems Engineering Institute, University of Applied Sciences Western Switzerland, Sion 1950, Switzerland
This study introduced the research and development of a portable and miniaturized system for the measurement of the refractive index of sub-microliter liquid based on a microfluidic chip. A technical method of double-beam interference, was proposed for use in the measurement. Based on this, by using a laser diode as a light source, changes in the refractive index were calculated by utilizing a complementary metal–oxide–semiconductor to detect the movement of interference fringes of the liquid. Firstly, this study simulated the effects of influencing factors on the interference infringes of two Gaussian beams, such as their spot sizes, distance between two beam spots, and detection range. Secondly, this research introduced the system design and construction of the double-beam interference method and analyzed the results of refractive index tests on sub-microliter aqueous glucose solutions with different concentrations. The measurement accuracy reached 10 4 refractive index units. This system has a compact structure and is rendered portable by using batteries for its power supply. The entire system is designed to be a double Z-shaped structure with a length of about 15 cm, a width of 5 cm, and a height of about 10 cm. It can be used to measure changes in the refractive index of sub-microliter to nanoliter liquids based on the use of a microfluidic chip.
120.3890 Medical optics instrumentation Chinese Optics Letters
2019, 17(4): 041201
上海理工大学教育部微创医疗器械工程研究中心生物医学光学与视光学研究所，上海 200093
糖尿病性黄斑水肿(DME)是导致成年人失明的主要原因之一，它的病理特征主要表现在视网膜内黄斑处液体的积聚。由于光学相干层析成像(OCT)具有无创性、成像安全快速等特点，在临床上被广泛用于眼科疾病的诊断。本文提出一种分割OCT图像中糖尿病性黄斑水肿的方法，首先通过对图像的预处理，排除散斑噪声和血管对最终分割结果的影响，再用改进的水平集方法有效地解决分割的问题，并计算水肿区域的面积，为后期的临床诊断治疗提供定性和定量的工具，最后将本文方法在15 个患有DME 成人的OCT 视网膜图像上进行验证。结果表明：囊状水肿分割的精确度、灵敏度和Dice 相似性系数分别为81.12%、86.90%、80.05%。
糖尿病性黄斑水肿 光学相干层析成像 水平集 图像分割 diabetic macular edema optical coherence tomography level set image segmentation
