基于穆勒矩阵的偏振显微镜及其在生物医学领域的应用

摘要

Polarized light microscopy is widely used in observation of optical anisotropic characteristics of samples. It has been applied to the studies in many ifelds, such as the geology of rocks and minerals, analysis of mural pigment, inspection of textiles, and detection of biological tissues. In biomedical studies, polarized light microscopy can provide rich micro structural information, which can be useful for the detection of abnormal tissues. However, the orientation distribution of anisotropic samples can inlfuence the polarization measurement. Recently, we designed a new type of polarized light microscopy based on Mueller matrix imaging method. In this microscopy all the elements of the Mueller matrix are simultaneously determined from the analysis in the frequency domain of the time-dependent intensity of the light beam at every pixel of the camera. The variations in intensity are created by the two compensators continuously rotating at different angular frequencies. Through the subsequent transformation processing of the received polarization image, we can reduce the inlfuence of sample orientation on polarization measurement and obtain the micro structural information more effectively. With the advantages of simple structure, rapid measurement and high precision, polarized light microscopy based on Mueller matrix shows a good development prospect.%偏振光显微镜可用于观察具有光学各向异性特征的样品，因而在诸多领域都得到广泛应用，例如研究地质岩石和矿物，分析壁画颜料，检验纺织品和生物组织等。在生物医学研究领域，偏振光显微镜能提供比普通光成像更丰富的微观结构信息，是一种有潜力的疾病诊断手段。然而在实际应用中各向异性样品的取向会对偏振测量产生一定影响。最近，我们设计了一种基于穆勒矩阵的全偏振显微镜，其主要依据穆勒矩阵双波片旋转测量方法[1]，通过在普通显微镜上添加起偏和检偏装置零件，利用计算机控制双波片旋转并定时采集图像，最后处理图像获取被观测样品的穆勒矩阵。通过后续对所获偏振图像进行分解、变换等处理，我们可以减少样品取向对偏振测量产生的影响，更有效的获取样品微观结构信息。基于穆勒矩阵的全偏振显微镜具有结构简单，测量快速，精度高等优点，有良好的开发应用前景。文中将详细介绍此种显微镜的原理，计算方法，误差校准，并演示其在生物医学样品的测量结果。