基于高光谱融合信息的火龙果遥感估产方法

Remote sensing method for pitaya yield estimation based on hyperspectral fusion information

  • 摘要: 【目的】探究基于高光谱融合信息的火龙果遥感估产方法,为地方政府优化农业产业结构、指导农业生产及推动水果产业高质量发展提供技术支撑。【方法】以盛果期单株火龙果为试验对象,融合成像与非成像高光谱信息,采用连续投影算法(SPA)筛选对产量敏感的波段作为自变量,以地面实测单株产量为响应变量。按2∶1的比例将126个采样点划分为建模集(84个)与验证集(42个),分别构建基于多元线性回归(MLR)、偏最小二乘回归(PLSR)、支持向量回归(SVR)及狮群优化算法支持向量回归(LSOA-SVR)的产量反演模型,评估单传感器及多传感器融合模型的估算精度。【结果】火龙果植株冠层成像与非成像高光谱反射率特征曲线基本一致,可见光区域反射率较低,近红外区域反射率较高;可见光区域中,绿光波段呈现反射峰,红光波段和蓝光波段则为吸收谷;冠层非成像高光谱近红外区域反射率与单株产量呈负相关,产量较低的单株光谱反射率较高;冠层成像和非成像高光谱反射率分别为44.6%和63.5%。果实成像与非成像高光谱反射率与火龙果单株产量的极显著相关(P<0.01)波段主要集中在398~704 nm。基于单一传感器数据构建的各类火龙果产量反演模型,MLR模型精度最低,PLSR模型次之,SVR模型最优。基于多传感器融合数据构建的4种模型,SVR模型精度优于MLR和PLSR模型,经狮群优化后的LSOA-SVR模型进一步提升了预测性能。【结论】通过融合成像与非成像高光谱信息,多源数据协同可明显提升盛果期火龙果产量遥感反演精度。基于单一传感器数据构建的产量反演模型中,非线性模型SVR优于线性模型PLSR和MLR。将LSOA应用于SVR模型参数寻优,构建的LSOA-SVR模型能有效提升火龙果单株产量遥感反演模型的预测精度。

     

    Abstract: 【Objective】This study aimed to investigate remote sensing method for pitaya yield estimation based on hyperspectral fusion information, thereby providing technical support for local governments to optimize agricultural industrial structure, guide agricultural production, and promote high-quality development of the fruit industry.【Method】Using single pitaya plants at full fruiting stage as the experimental subjects, the imaging and non-imaging hyperspectral information was fused, and the continuous projection algorithm (SPA) was employed to select yield-sensitive bands as independent variables and ground-measured yield per plant as the response variable. At a ratio of 2∶1, 126 sampling sites were divided into the modeling set (84 sites) and validation set (42 sites), and yield inversion models based on multiple linear regression (MLR), partial least squares regression (PLSR), support vector regression (SVR), and lion swarm optimization algorithm-support vector regression (LSOA-SVR) were established to evaluate estimation accuracy of single-sensor and multi-sensor fusion models.【Result】The imaging and non-imaging hyperspectral reflectance feature curves of pitaya plant canopy were basically consistent, with lower reflectance in the visible light region and higher reflectance in the near-infrared region. Within the visible light region, the green bands showed a reflection peak, while the red and blue bands showed absorption troughs. Reflectance of the canopy in non-imaging hyperspectral near-infrared region was negatively correlated with yield per plant, with low-yield plants showing higher spectral reflectance, and the imaging and non-imaging hyperspectral reflectance of canopy were 44.6% and 63.5% respectively. The extremely significant correlated (P<0.01) bands between imaging and non-imaging hyperspectral reflectance of fruit as well as pitaya yield per plant were mainly concentrated in 398-704 nm. According to pitaya yield inversion models based on single-sensor data, the MLR model had the lowest accuracy, followed by the PLSR model, and the SVR model was the best. Based on the four models based on multi-sensor fusion data, the SVR model had better accuracy than the MLR and PLSR models, and the LSOA-SVR model after lion swarm optimization algorithm further improved the performance of prediction.【Conclusion】By fusing imaging and non-imaging hyperspectral information, multi-source data collaboration can significantly improve the accuracy of remote sensing inversion for yield of pitaya at full fruiting stage. In yield inversion models based on single-sensor data, the nonlinear model SVR outperforms the linear models PLSR and MLR. As applying LSOA in parameter optimization of SVR model, the proposed LSOA-SVR method can effectively improve prediction accuracy of the remote sensing inversion model for pitaya yield per plant.

     

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