刷胶处理对土壤剖面高光谱反射率的系统性影响研究

Systematic effects of gluing treatment on hyperspectral reflectance of soil profiles

关键词:  土壤剖面  高光谱遥感  光谱反射率  胶粘剂  方法学误差

Key words:  soil profiles  hyperspectral remote sensing  spectral reflectance  adhesive  methodological error

摘要:

【目的】 定量评估刷胶固定处理对土壤剖面高光谱反射特征的系统性影响（如反射率下降幅度、相对变化率等），为推进土壤高光谱测量标准化工作提供支持。【方法】 文章选取4个典型土壤剖面，使用SOC710VP成像光谱仪分别采集刷涂水性胶粘剂前、后的高光谱图像；对图像进行光谱标定、Savitzky-Golay滤波降噪等预处理后，依据诊断发生层划分结果提取各层所有像素的光谱数据，构建以发生层为样本、128个波段反射率为特征的数据集，进而开展对比分析。【结果】 （1）刷胶处理后，所有发生层在各波段的反射率均出现普遍性、统计显著的下降，表明胶水在土壤表面形成了吸光层，改变了原始光谱信号；（2）该衰减效应兼具波段特异性与发生层差异性—水分强吸收波段及粘土矿物特征波段附近的反射率下降尤为剧烈，不同发生层则因自身理化性质差异，对刷胶的响应模式与强度呈现规律性变化。【结论】 刷胶固定法会系统性地扭曲土壤剖面的原始光谱信息，尤其危及基于特征波段的土壤水分与矿物属性的定量反演精度。研究建议在高精度土壤光谱应用中审慎使用刷胶固定法，或需开发相应的校正模型以消除其系统性偏差，从而提升土壤剖面光谱数据的可靠性与可比性。

Abstract:

[Purpose] This study aims to quantify the systematic impact of gluing fixation on the hyperspectral reflectance characteristics of soil profiles，such as the magnitude of reflectance decrease and relative change rates，to provide support for promoting the standardization of soil hyperspectral measurement.[Method] Four typical soil profiles were selected in this study，and a SOC710VP imaging spectrometer was used to collect hyperspectral images both before and after the application of a water-based adhesive. After performing preprocessing steps on the images，including spectral calibration and Savitzky-Golay filtering for noise reduction，spectral data of all pixels in each layer was extracted according to the division results of diagnostic genetic horizons. A dataset with genetic horizons as samples and the reflectance of 128 bands as features was then constructed，followed by a comparative analysis.[Result] （1）After the gluing treatment，the reflectance of all genetic horizons showed a universal and statistically significant decrease across all bands，indicating that the adhesive formed a light-absorbing layer on the soil surface，which altered the original spectral signals. （2）The attenuation effect exhibited both band-specific and horizon-specific characteristics：the reflectance decreases most significantly near the strong water absorption bands and characteristic bands of clay minerals；meanwhile，different genetic horizons showed regular variations in their response patterns and intensities to the gluing treatment due to their distinct physicochemical properties.[Conclusion] The gluing fixation method systematically distorts the original spectral information of soil profiles，especially jeopardizing the accuracy of quantitative inversion of soil moisture and mineral properties based on characteristic bands. This study suggests that the gluing fixation method should be used cautiously in high-precision soil spectral applications，or corresponding correction models need to be developed to eliminate its systematic bias，thereby improving the reliability and comparability of soil profile spectral data.