Kakuta Naoto, Arimoto Hidenobu, Momoki Hideyuki, Li Fuguo, Yamada Yukio
Faculty of Engineering, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, 812-8581 Japan.
Appl Opt. 2008 May 1;47(13):2227-33. doi: 10.1364/ao.47.002227.
We report a method that uses near-infrared spectroscopy and multivariate analysis to measure the temperature of turbid aqueous solutions. The measurement principle is based on the fact that the peak wavelength of the water absorption band, with its center near 1440 nm, shifts with changes in temperature. This principle was used to measure the temperatures of 1 mm thick samples of aqueous solutions containing Intralipid (2%), which are often used as optical phantoms for biological tissues due to similar scattering characteristics. Temperatures of pure water and aqueous solutions containing glucose (100 mg/ml and 200 mg/ml) were also measured for comparison. For the turbid Intralipid solutions, the absorbance spectrum varied irregularly with time due to the change in scattering characteristics. However, by making use of the difference between the absorbance at 1412 nm and the temperature-independent absorbance at 1440 nm, we obtained SEPs (standard error of prediction) of 0.3 degrees C and 0.2 degrees C by univariate linear regression and partial least squares regression, respectively. These accuracies were almost the same as those for the transparent samples (pure water and glucose solution).
我们报告了一种使用近红外光谱和多变量分析来测量浑浊水溶液温度的方法。测量原理基于这样一个事实，即中心位于1440 nm附近的水吸收带的峰值波长会随温度变化而移动。该原理用于测量含有英脱利匹特（2%）的1毫米厚水溶液样本的温度，由于其散射特性相似，英脱利匹特常用于作为生物组织的光学模型。还测量了纯水以及含有葡萄糖（100毫克/毫升和200毫克/毫升）的水溶液的温度以作比较。对于浑浊的英脱利匹特溶液，由于散射特性的变化，吸光度光谱随时间不规则变化。然而，通过利用1412 nm处的吸光度与1440 nm处与温度无关的吸光度之间的差异，我们通过单变量线性回归和偏最小二乘回归分别获得了0.3摄氏度和0.2摄氏度的预测标准误差（SEP）。这些精度与透明样本（纯水和葡萄糖溶液）的精度几乎相同。
