摘要
基于共焦模式的OCT蒙特卡罗仿真模型，研究了在OCT系统中高散射生物组织背向散射光的反射率。仿真结果：表明对OCT成像有贡献的背向散射光强是样品臂入射光强的10^-8～10^-10，这样微弱的有用信号限制OCT系统的成像速度、探测灵敏度、信噪比和图像对比度等系统的性能。为此设计了一种带有特殊镀膜分束器的OCT系统。采用这种结构的分柬器，第一，在保证入射光对生物组织无热损伤的情况下，可以尽量提高光源的输出功率，改进之后的干涉仪可以使参考光衰减4个量级，因此不会使光电探测器的输出轻易达到饱和状态。第二．大幅度减小了参考光与信号光之间的能量差距，图像干涉对比度大约提高2个数量级，即使在高速成像的情况下，仍然能够使OCT系统具备较高的成像质量。第三，这种特殊结构的干涉仪可以使样品臂的入射光最强，并将背向散射信号光因分束器反射的损失减少到最低程度，从而使系统的信噪比提高了6dB，并通过对样品的测试可以测得系统的探测灵敏度可以提高到43dB。
OCT Monte-Carlo simulation model based on confocal mode is used to study the reflectivity of back-scattering light from high scattering tissue in OCT system, the simulation result shows that the intensity of useful back-scattering light for OCT imaging is about 10^-8-10^-10 of incidence light. The weak but useful signal limits the OCT imaging speed, detection sensitivity, signal-to-noise ratio and image contrast. Therefore, a new special coating beam splitter was devised. As a result, firstly by enhancing the output power of lamp-house to a large possible degree while being assure that tissues are not scathed, the new coating beam splitter causes the intensity of referential light to be reduced by four orders, and the output power of electrophotonie detector can not easily reach saturation. Secondly, the intensity gap between referential and signal beam is largely reduced, and image intervening contrast is increased by two orders. In spite of imaging at high speed, OCT system yet has qualified images. Thirdly, specially designed system renders sample arm with most intensive light and lessens the loss of back-scattering light to the least degree, therefore, signal-to-noise ratio improves by 6 dB and detection sensitivity of the system increases to 43 dB by actual sample test.
出处
《光学精密工程》
EI
CAS
CSCD
北大核心
2006年第6期1082-1087,共6页
Optics and Precision Engineering
基金
国家自然科学基金资助项目(No.60174032)
关键词
特殊镀膜分束器
信噪比
信号灵敏度
图像对比虚
special coating beam splitter
signal-to noise ratio
detection sensitivity
image contrast
