粗糙度对岩石热红外光谱解混影响的实验研究

A Study on the Effects of Roughness on Thermal Infrared Spectral Unmixing of Rock

现有的岩石热红外光谱解混,大多针对颗粒岩石,无法满足自然界块状岩石高精度光谱解混的要求。研究将粗糙度作为影响光谱发射率与解混精度的考虑因素,研究块状岩石的热红外光谱解混问题。以自然岩石表面形态为依据,设计了三个粗糙度等级;顾及到岩石的结构情况,采用矿物块体拼接的方法模拟制作了3种块状岩石;通过相同和不同粗糙度的解混实验,来研究自然界块状岩石的表面粗糙度对岩石光谱特征和光谱解混的影响规律。结果表明,当矿物端元与岩石在相同粗糙度下光谱线性解混时,效果较好;而在不同粗糙度下解混时,60个解混结果中有48.3%误差超过5%,最大达到25.3%。基于此,建议在实际岩矿高光谱定量遥感中,应该充分考虑粗糙度对光谱解混的影响。

The current unmixing of rock thermal infrared spectrum mostly focuses on granule forms,which can＇t meet the requirements of high accuracy when applied to natural massive rocks.This paper aims to study the influence of rock surface roughness on spectral unmixing,which will influence the spectral emissivity and unmixing accuracy.Three grades of roughness were defined according to the natural rock surface morphology,and according to their structural forms,three kinds of samples were simulated by the method of mineral block mosaicking.The effects of roughness level on rock spectrum and unmixing were investigated by unmixing experiments using the same and different roughness grades.The results showed that good unmixing could be achieved when the mineral endmember and rock shared the same roughness,while in terms of different roughness grades,48.3% of the 60 unmixing results presented errors over 5%,and the maximum was 25.3%.Therefore,we suggest that the effects of roughness on spectral unmixing should be completely considered in the quantitative hyperspectral remote sensing of natural massive rock.