生物组织多光谱偏振特性研究

生物组织内部结构复杂且具有较强的散射特性,而光作为生物组织检测的重要信息载体,其自身特性包括颜色、幅值、偏振等都对信息获取有较大的影响.结合偏振成像,对生物组织多光谱偏振特性展开了研究,依据不同微粒尺寸的分布建立了均匀单层生物组织模型,结合瑞利和米氏散射理论模拟了基于单个微粒的两种散射事件.瑞利散射具有较好的前向后向散...

Study on Multispectral Polarization Characteristics of Biological Tissues

Biological tissues are very complicated with strong scattering characteristics. The light-source of detecting physiological parameters of tissues is critical. Combined with the advantages of polarization imaging, this paper studies the multispectral polarization characteristics of biological tissues. We established uniform monolayer biological tissue samples based on the distribution of different particle sizes and simulated the scattering model with single-particle by combining Rayleigh and Mie scattering theory. Rayleigh theory has good forward and backward scattering symmetry; Mie theory has strong forward scattering characteristics. The two scattering models are closely related to the size parameter, a dimensionless quantity, depending on the incident wavelength and the size of scattered particles. Mie theory is generally used as the research model in biological tissues. We used a Monte Carlo method to simulate the transmission characteristics of polarized light in the tissue model. The wavelength range is 400~1 000 nm. In this paper, we have simulated four typical polarization states, (horizontally polarized light, vertically polarized light, 450 linearly polarized light and right-rotated circularly polarized light). The experiment system used a white LED lamp as a light source. It used filters to obtain different wavelength beams, a color camera was used to record the image of the target, two groups of linear polarizers and right-rotated circular polarizers were used as polarizers and analyzers to test horizontally polarized light, and right-rotated circular polarized light with wavelengths of 450, 525, 550, 590, 610, 650 and 690 nm, respectively, and the target is our palm. Both simulation and experimental results show that with the increase of wavelength, the degree of polarization (DOP) of linearly polarized light after backscattering from skin tissue shows an overall upward trend, while that of circularly polarized light is on the decline. However, the overall DOP of circularly polarized light is higher than that of linearly polarized light, which indicates that circularly polarized light has better polarization retention than linearly polarized light in biological tissues and is more suitable for detecting physiological information. Our study has confirmed the multispectral characteristics of circularly polarized light and linearly polarized light transmitted in tissues, which provided theoretical support for obtaining multispectral polarization physiological parameters.