拉曼高光谱成像系统中光在奶粉层的穿透深度研究

发布时间：2018-03-31 04:21

本文选题：拉曼光谱　切入点：高光谱成像　出处：《光谱学与光谱分析》2017年10期

【摘要】：拉曼高光谱成像技术不仅可以获取样本的空间分布信息,图像上每个像素点还包括了完整的光谱信息,因其信息量丰富的特点已在食品安全检测方面得到了应用。本研究探索拉曼高光谱成像系统中光在奶粉层中的穿透深度,以及采集参数和奶粉类型对穿透深度的影响。实验选取均匀奶粉层样品放置于厚度为5mm的三聚氰胺样本之上,检测奶粉层厚度为0.8~4.0mm时的三聚氰胺特征峰强度,以此评估光在奶粉层中的穿透性和信号衰减情况。结果显示当奶粉层厚度一定时,随着激光功率变大,拉曼特征峰值随之增加,此外更长的曝光时间也可以使拉曼信号得到增强。在激光功率不小于2 W且曝光时间不小于500ms时,光在全脂奶粉层的穿透深度可达4mm。奶粉层厚度在0.8~4.0mm范围内,穿透奶粉层的拉曼信号随着奶粉层厚度增加呈指数式衰减。在激光功率为8W、曝光时间为1 000ms的条件下,光在全脂、低脂和脱脂奶粉层的穿透深度均达到了4mm。在相同测量厚度下,通过脱脂奶粉层接收的拉曼信号弱于通过全脂和低脂奶粉层接收的拉曼信号强度。研究结果为拉曼高光谱检测中奶粉样品的前处理提供了有益参考。
[Abstract]:Raman hyperspectral imaging can not only obtain the spatial distribution of samples, but also include complete spectral information for each pixel in the image. Because of its rich information, it has been applied in food safety detection. In this study, the penetration depth of light in milk powder layer in Raman hyperspectral imaging system was explored. And the influence of sampling parameters and milk powder type on penetration depth. The uniform milk powder layer sample was selected to place on the melamine sample with thickness of 5mm, and the characteristic peak strength of melamine was detected when the thickness of milk powder layer was 0.8~4.0mm. The results show that the Raman characteristic peak increases with the laser power increasing when the thickness of the layer is constant. When the laser power is not less than 2 W and the exposure time is not less than 500ms, the penetration depth of the whole milk powder layer can reach 4 mm. the thickness of the milk powder layer is in the range of 0.8~4.0mm. When the laser power is 8 W and the exposure time is 1 000ms, the penetration depth of the whole fat, low fat and skim milk powder layers reaches 4 mm. at the same measuring thickness, the Raman signal of the penetrating milk layer decreases exponentially with the increase of the thickness of the milk powder layer, and the laser power is 8 W and the exposure time is 1 000ms. The intensity of Raman signal received by skim milk powder layer is weaker than that by whole fat and low fat milk powder layer. The results provide a useful reference for the pretreatment of milk powder sample in Raman hyperspectral detection.
【作者单位】：西北农林科技大学机械与电子工程学院;国家农业智能装备工程技术研究中心;农业部农业信息技术重点实验室;农业智能装备技术北京市重点实验室;
【基金】：北京市农林科学院青年科研基金(QNJJ201423) 国家自然科学基金项目(31501216)资助
【分类号】：O657.37;TS252.51

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