Abstract Spectral data are now-a-days widely used for assessment of biochemical, biophysical and structural traits of vegetation by analysing their spectral signatures. In field, spectral data is recorded by hand held spectroradiometer. In doing so, the spectral data acquisition is influenced by several factors such as variations in light intensity during recording; number of spectral readings per plant; distance between sensor and plant; impact of heating due to sun, wind, and wetness of plants. These standard operating practices for such data acquisition are generally based on the similar work carried out by researchers in bits and pieces. In the present study experimental set-ups have been laid for systematic studies to answer the influence of above factors and spectral data and required optimisations have been suggested. It was found that variations in light intensity influence the spectral readings, when the illumination difference was more than ∼20%. The 30 spectral readings were found optimum. The reflectance spectra recorded at distance of 20-35 cm were treated as pure spectra in case of 25 °FOV sensors. The heating of samples due to sun, speed and direction of wind, and wetness of samples influenced the plant spectral reflectance and were more pronounced in the NIR regions. It was also observed that averaging of spectra recorded in several observations (instead of single observation) for the same plant samples optimize the errors. It was concluded in order to have a good quality of vegetation field spectral data, case to case calibrations, and care must be taken to eliminate influence of surrounding environmental variables while spectral data acquisition to avoid/minimize the errors.

中文翻译：

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使用手持非成像光谱传感器重新审视和优化植被的光谱数据收集技术，以最大限度地减少误差

摘要 光谱数据现在被广泛用于通过分析植被的光谱特征来评估植被的生化、生物物理和结构特征。在现场，光谱数据由手持光谱仪记录。在此过程中，光谱数据采集受到多种因素的影响，例如记录期间光强度的变化；每株植物的光谱读数数量；传感器与植物之间的距离；由阳光、风和植物的潮湿引起的加热影响。此类数据采集的这些标准操作实践通常基于研究人员在零碎中进行的类似工作。在本研究中，已经为系统研究奠定了实验装置，以回答上述因素和光谱数据的影响，并提出了所需的优化。发现当光照差异超过 20% 时，光强度的变化会影响光谱读数。发现 30 个光谱读数最佳。在 25°FOV 传感器的情况下，在 20-35 cm 距离处记录的反射光谱被视为纯光谱。由于太阳、风速和风向以及样品的湿度对样品的加热影响了植物的光谱反射率，并且在 NIR 区域更为明显。还观察到，对相同植物样本的多次观察（而不是单个观察）中记录的光谱进行平均可以优化误差。得出结论是为了获得高质量的植被野外光谱数据、个案校准、