Aouali A, Chevalier S, Sommier A, Abisset-Chavanne E, Batsale J-C, Pradere C
Arts et Métiers Institute of Technology, Université de Bordeaux, CNRS, INRA, INP, I2M, HESAM, Esplanade des Arts et Métiers, 33400, Talence, France.
I2M TREFLE, UMR 5295 CNRS-UB-ENSAM, Esplanade des Arts et Metiers, 33405, Talence, France.
Sci Rep. 2020 Dec 18;10(1):22310. doi: 10.1038/s41598-020-78887-x.
This work reports a multispectral tomography technique in transmission mode (called 3DITI for 3D Infrared Thermospectroscopic Imaging) based on a middle wavelength infrared (MWIR) focal plane array. This technique relies on an MWIR camera (1.5 to 5.5 μm) used in combination with a multispectral IR monochromator (400 nm to 20 μm), and a sample mounted on a rotary stage for the measurement of its transmittance at several angular positions. Based on the projections expressed in terms of a sinogram, spatial three-dimensional (3D) cubes (proper emission and absorptivity) are reconstructed using a back-projection method based on inverse Radon transform. As a validation case, IR absorptivity tomography of a reflective metallic screw is performed within a very short time, i.e., shorter than 1 min, to monitor 72 angular positions of the sample. Then, the absorptivity and proper emission tomographies of a butane-propane-air burner flame and microfluidic perfluoroalkoxy (PFA) tubing filled with water and ethanol are obtained. These unique data evidence that 3D thermo-chemical information in complex semi-transparent media can be obtained using the proposed 3DITI method. Moreover, this measurement technique presents new problems in the acquisition, storage and processing of big data. In fact, the quantity of reconstructed data can reach several TB (a tomographic sample cube of 1.5 × 1.5 × 3 cm is composed of more than 1 million pixels per wavelength).
这项工作报道了一种基于中波红外（MWIR）焦平面阵列的透射模式多光谱层析成像技术（称为3D红外热光谱成像，即3DITI）。该技术依赖于一台MWIR相机（1.5至5.5μm），与一台多光谱红外单色仪（400nm至20μm）联合使用，以及一个安装在旋转台上的样品，用于在几个角度位置测量其透过率。基于以正弦图表示的投影，使用基于逆拉东变换的反投影方法重建空间三维（3D）立方体（固有发射率和吸收率）。作为一个验证案例，在非常短的时间内（即短于1分钟）对一个反射性金属螺钉进行红外吸收率层析成像，以监测样品的72个角度位置。然后，获得了丁烷 - 丙烷 - 空气燃烧器火焰以及充满水和乙醇的微流体全氟烷氧基（PFA）管的吸收率和固有发射率层析成像。这些独特的数据证明，使用所提出的3DITI方法可以获得复杂半透明介质中的三维热化学信息。此外，这种测量技术在大数据的采集、存储和处理方面提出了新的问题。实际上，重建数据的量可以达到数TB（一个1.5×1.5×3cm的层析样品立方体每个波长由超过100万个像素组成）。
