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Optical Computed Tomography by Detection of Photons Preserving initial Polarization Through a Scattering Medium

通过检测通过散射介质保持初始偏振的光子进行光学计算机断层扫描

基本信息

批准号：
09555016
负责人：
HORINAKA Hiromichi
金额：
$ 4.67万
依托单位：
Osaka Prefecture University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

项目摘要

An optical CT apparatus using photons preserving initial polarization was designed on the basis of results of fundamental experiments. A diode laser, a phase-modulator, a translation stages and a detector were mounted on a small optical bread board. A personal computer was used for three purposes; control of translation stages and the gain of the lock-in amplifier, acquisition of the projection data and reconstruction of the optical CT image. The apparatus had the ability to suppress the diffused light in the transmitted light up upto 110dB.The following applications of the optical CT apparatus were investigated.(1) Two dimensional distribution of fruits ingredientsOur optical CT apparatus was applied to a pimento and a summer orange and their optical CT images were reconstructed from projection data. The internal section and the core were able to be recognized, although the spatial resolution of images was not sufficient. Three diode lasers, which had different emission wavelengths in … More dividually corresponding to the absorption lines of water, sugar (sucrose) and chlorophyll A were employed to take the projection data of the fruit. Two dimensional distribution of absorption coefficient of the reconstructed images depended on the wavelength of laser. It means the possibility that two dimensional distribution of every ingredient in food is obtained by our apparatus.(2) Detection of foreign matter in foodX ray is applicable to the detection of metals in food, but is not effective for pieces of plastics. Our apparatus was applied to detection of foreign matter in food. The projection data of the milk in a bottle in which a piece of plastic was set as a foreign matter. The existence of a piece of plastic was clearly recognized in the reconstructed image. The image by our method is easily influenced by the change of refractive index, which is common problem in the methods detecting photons travelling near the straight line. The sensitivity of our method to the boundary of refractive indices is also expected to be used for the detection of foreign matter in food. Less

根据基础实验的结果，设计了一种使用保持初始偏振的光子的光学CT装置。二极管激光器、相位调制器、平移台和探测器安装在小型光学面包板上。个人计算机有三个用途：控制平移台和锁定放大器的增益、采集投影数据和重建光学 CT 图像。该装置能够将透射光中的漫射光抑制高达110dB。研究了光学CT装置的以下应用。(1)水果成分的二维分布我们的光学CT装置应用于多椒和夏橙，并根据投影数据重建了它们的光学CT图像。尽管图像的空间分辨率不够，但内部部分和核心能够被识别。使用三个二极管激光器来获取水果的投影数据，这三个二极管激光器具有不同的发射波长，分别对应于水、糖（蔗糖）和叶绿素 A 的吸收线。重建图像吸收系数的二维分布取决于激光的波长。这意味着我们的设备有可能获得食品中每种成分的二维分布。 (2)食品中异物的检测X射线适用于检测食品中的金属，但对塑料件无效。我们的设备应用于食品中异物的检测。瓶子里的牛奶的投影数据，其中一块塑料被设置为异物。在重建图像中可以清楚地识别出一块塑料的存在。我们的方法的图像很容易受到折射率变化的影响，这是检测沿直线传播的光子的方法中的常见问题。我们的方法对折射率边界的敏感性也有望用于食品中异物的检测。较少的