高光谱图像空间频谱信息大气传输特征研究

Airborne and spaceborne hyperspectral images quality is affected by atmosphere. At present, the studies on mechanism of hyperspectral image degradation in atmosphere and correction method are both in spatial domain, while in spatial frequency domain are rare. Additionally, the classical model of MTF which is the characteristic parameter representing atmospheric effect in spatial frequency domain is limited by small angle scattering approximation and not including all atmospheric effect factors. The project is to study the physical mechanism of hyperspectral image degradation in spatial frequency domain in atmosphere. The MTF model of inhomogeneous turbid atmosphere will be derived through theoretical analysis which is not depend on small angle scattering approximation and includes almost all atmospheric effect factors. The MTF model will be verified through experiment and comparing with classical MTF model by numerical simulation. Subsequently based on the MTF model, atmospheric transmission characteristic of different spatial frequency spectrum components of different waveband hyperspectral images under actual atmospheric conditions will be studied thoroughly. The study has great significance to understand profoundly atmospheric transmission degradation process of hyperspectral images, and provide a novel perspective for atmospheric correction and dimensional reduction through selecting wavebands whose spatial frequency spectrum components have high transmission property, which can further more improve the precision of quantitative reversion and target recognition.

航空和航天获取的高光谱图像的质量受到大气的影响，目前高光谱图像大气传输退化机理及校正方法的研究均是在空域中进行，从空间频域的角度分析鲜有报道，同时空间频域中定量描述大气影响程度的特征参量—调制传递函数MTF的传统模型的应用范围和精度受限于小角散射近似和考虑退化因素不全面的缺点。本项目正是从空间频域研究混浊大气中高光谱图像退化的物理机理，通过严谨的理论分析建立不依赖于小角散射近似、以及较全面考虑图像退化大气影响因素的非均匀混浊大气MTF模型，并通过实验测量进行校验，以及通过数值模拟与传统MTF模型进行对比分析；基于此模型，深入研究不同大气条件下可见光-红外波段高光谱图像不同波段不同空间频谱分量的大气传输特征。该研究可深入认识高光谱图像大气传输退化过程，并可为高光谱图像空间频域大气校正方法、以及通过选择具有频谱分量高通特性的波段实现降维优化提供一个新颖视角，进一步提高定量反演和目标识别的精度。

混浊大气对图像空间频谱分量的影响采用调制传递函数（MTF）定量表征。本项目从空间频域研究了混浊大气中高光谱图像退化的物理机理，通过严谨的理论分析建立了不依赖于小角散射近似、以及较全面考虑图像退化大气影响因素的非均匀混浊大气表观MTF模型，并通过实验测量进行校验，以及通过数值模拟与传统MTF模型进行对比分析，结果表明建立的表观MTF模型与实测结果具有较好的一致性，并优于小角散射近似模型；基于此模型，深入研究了不同大气条件下可见光-红外波段高光谱图像不同波段不同空间频谱分量的大气传输特征，建立了一种新的成像波段优选准则。该研究给出了一种从空间频域和光谱域两个方面耦合探究高性能探测成像与识别的新颖视角，可应用于高光谱图像空间频域大气校正方法，以及优选成像波段以抑制大气影响，在不同实际应用环境下较为明显地提高敏感目标探测与识别的能力。