不同采样间隔下分数阶微分对土壤重金属高光谱数据的影响

Effect of Fractional Differential on Soil Hypermetallic Hyperspectral Data at Different Sampling Intervals

为研究不同采样间隔下分数阶微分对光谱反射率和土壤重金属含量之间相关系数的影响,对土壤光谱以15、25、35和45 nm间隔重新采样,然后对其进行对应的0～2阶(间隔0.2阶)微分处理,比较分析各阶微分在各种采样间隔下与土壤重金属相关系数的变化趋势。研究结果表明:当微分阶数增大时,具有0.01极显著相关水平的波段数目整体呈现先增加后减小的趋向,且15 nm重采样间距提升相关性的效果优于其他3种采样间隔; 15、25、35和45 nm的相关系数绝对值分别在1.6、1.2、2和2阶微分达到最大。

In order to study the effect of fractional differential under different sampling intervals on the correlation coefficient between spectral reflectance and soil heavy metal content,the soil spectrum are resampled at 15,25,35 and 45 nm intervals,and then the corresponding 0 ～ 2 order（ interval 0. 2 order） differential processing is performed to compare and analyze the variation trend of correlation coefficient between each order differential and the soil heavy metal at various sampling intervals.The results show that when the differential order increases,the number of bands having a significant correlation level of 0. 01 generally increases first and then decreases and the effect of improving the correlation by 15 nm resampling interval is better than the other three sampling intervals. And the absolute values of correlation coefficients of 15,25,35 and 45 nm reach the maximum in 1.6,1.2,2 and 2 orders respectively.