[目的]以延河流域为研究区,利用自动提取算法建立典型黄土的土壤线方程,为土壤调节植被指数的计算提供基本参数。[方法]基于Landsat 8OLI遥感影像,采用自动提取算法获取土壤线参数;分析归一化植被指数NDVI,土壤调节植被指数PVI,TSAVI,ATSAVI与实测盖度的相关性,探讨所构建的土壤线方程在黄土高原地区植被指数提取中的适用性。[结果]通过自动算法与常规方法对比发现两者偏差较小,且自动提取算法具有较高的精度和稳定性;各植被指数与实测盖度的相关性大小为:PVI〉NDVI〉TSAVI〉ATSAVI,PVI为延河流域植被盖度反演的最优植被指数,NDVI次之,TSAVI与ATSAVI较差;与NDVI指数相比,PVI指数能够较好地抵抗土壤噪声的影响,对不同植被类型的敏感性较高,更适用于植被覆盖度较低的黄土高原。[结论]自动提取算法对延河流域土壤线的提取较为适用,所得参数适合于计算土壤调节植被指数。
[Objective]Taking Yanhe River basin as a study area,typical loess soil line equation was established by automatic algorithm to provide basic parameters for the calculation of the soil adjusted vegetation index.[Methods]Based on Landsat 8OLI images,soil line was extracted by automatic algorithm,then the correlation coefficients between normalized difference vegetation index(NDVI),perpendicular vegetation index(PVI),transformed soil-adjusted vegetation index(TSAVI),adjusted transformed soil-adjusted vegetation index(ATSAVI)and test coverage were calculated;and the applicability of soil line equation in vegetation index extraction was also discussed in the Loess Plateau.[Results](1)Compared with conventional method,the difference was small,and the automatic algorithm had high accuracy and stability;(2)The sequence of the correlation between vegetation index and test coverage was:PVI 〉NDVI 〉TSAVI〉ATSAVI,which showed that PVI was the optimal vegetation index,NDVI was the next,TSAVI and ATSAVI were the worst to the extraction of vegetation coverage in Yanhe river basin;(3)Compared with NDVI,PVI index could reduce the influence of soil noise,and its sensitivity to different vegetation types washigher.PVI was more suitable for the Loess Plateau with low vegetation coverage.[Conclusion]It is suitable to extract the soil line by automatic extraction algorithm in Yanhe river basin,and the parameters can be used to calculate the soil-adjusted vegetation index.