基于LCTF调谐的高光谱成像系统设计

Design of Hyperspectral Imaging System Based on LCTF

提出一种新的轻小型高光谱成像系统,将液晶可调谐滤光片LCTF应用于高光谱成像技术,用电调谐的LCTF代替传统的机械滤光片转轮,在可见-近红外波段上可快速地实现波长的任意调谐。系统由光学镜头、LCTF和CCD探测器组成。文章首先详细描述了系统结构、光学设计及其工作原理;再利用该成像系统,以飞艇为平台进行了野外试验,获取了高光谱立体图像,所获取的图像有较高的空间分辨率和光谱分辨率;文章给出16个波段中546～600nm的局部图像数据,最后对图像进行初步的数据处理,推导出地物420～720nm的光谱反射率。试验验证了该成像系统的高光谱数据成像获取能力,成像数据可应用于光谱分析。

A new compact lightweight imaging system for hyperspectral imaging is described. The system can be thought of as the substitute for traditional mechanical filter-wheel sensor. The system is based on different techniques. It uses an electronic controlled LCTF（liquid crystal tunable filter） which provided rapid and vibrationless selection of any wavelength in the visible to IR range. The imaging system consisted of an optic lens, a CRI VariSpec LCTF and a Dalsa 1M30 camera. First the outline of this system setup is presented, then the optics designed is introduced, next the working principle of LCTF is described in details. A field experiment with the imaging system loaded on an airship was carried out and collected hyperspectral solid image. The images obtained had higher spectral and spatial resolution. Some parts of the 540-600 nm components of the 16-band image cube were also shown. Finally, the data acquired were rough processed to get reflection spectrum（from 420 to 720 nm） of three targets. It is concluded that the experiment has proved that the imaging system is effective in obtaining hyperspeetral data. The image captured by the system can be applied to spectral estimation, spectra based classification and spectral based analysis.