协同Sentinel-2和GF-3多特征优选的农作物识别

    Crop identification by synergistic Sentinel-2 and GF-3 multi-feature optimization

    • 摘要: 农作物识别是精准农业的重要研究领域。在时空大数据和智能计算时代,如何充分挖掘和综合应用各种数据、方法和模型的优势是提高遥感农作物识别精度的有效途径。以安徽省颍上县为例,采用Sentinel-2和GF-3卫星影像数据,提取了包括光谱、指数、纹理和极化等在内的58个特征指标;随后分别选取3种特征优选算法和3种机器学习方法进行组合,设计了3种试验方案,探索特征选择和机器学习方法对农作物分类的影响;通过对比特征维度和分类精度,对各种分类方案进行评价。研究结果显示:红边特征在农作物识别中具有重要作用,同时纹理特征的加入也适当提高了分类精度;3种特征优选算法分别和随机森林方法组合时,分类精度是所有方案中排名最高的前3位;其中Relief F与随机森林组合在遥感农作物识别分类中效果最为显著,总体精度达到了93.39%,Kappa系数为0.8933,F1得分为93.31%;比Relief F结合极限梯度提升和支持向量机分类方法的总体精度、Kappa系数、F1得分分别提高1.36个百分点、0.021和1.31个百分点,8.81个百分点、0.1312和8.78个百分点;在随机森林分类方法下,Relief F特征选择维度为28维,比随机森林的递归特征消除和卡方检验特征优选算法分别低4维和22维,充分证明了Relief F结合随机森林分类方法的有效性和先进性。该研究为精准农作物识别提供了新的技术思路。

       

      Abstract: The increasing severity of global climate change poses significant challenges to agricultural production and food security. In recent years, the Chinese government has placed considerable emphasis on the development of remote sensing technologies, achieving remarkable advancements, particularly in the field of satellite remote sensing, where China has established itself as a global leader. As an agricultural powerhouse, China recognizes the critical importance of enhancing the application of agricultural remote sensing monitoring to obtain timely and accurate information regarding crop types and planting structures. This information is vital for agricultural surveys, monitoring agricultural conditions, estimating crop yields, and assessing disaster impacts. Maximizing the utilization of existing remote sensing data and ground sample information, in conjunction with feature engineering techniques and machine learning methods for classification, is an essential pathway to improving crop classification accuracy. With the continuous advancement of remote sensing technology, quantitative remote sensing monitoring based on satellite-derived spatiotemporal big data has emerged as a crucial development direction in contemporary precision agriculture. While individual remote sensing imagery and multi-feature selection are indeed important for crop recognition and classification, substantial variations exist in the adaptability of feature selection algorithms and machine learning methods across different scenarios, leading to significant fluctuations in recognition effectiveness and classification accuracy. This study focuses on Ying Shang County in Anhui Province, employing Sentinel-2 and GF-3 satellite imagery data to extract 58 feature indicators, including spectral, index, texture, and polarization characteristics. Subsequently, three feature selection algorithms and three machine learning methods were selected and combined, designing three experimental schemes to explore the effects of feature selection and machine learning techniques on crop classification. By comparing feature dimensions and classification accuracy, the effectiveness of various classification schemes was thoroughly evaluated. The research findings reveal several key insights: (1) The application of feature selection algorithms effectively facilitates dimensionality reduction, avoiding the data redundancy associated with excessively high dimensions. Among the algorithms assessed, Relief F demonstrated significant capability in reducing feature dimensions while maintaining effective crop classification performance. Specifically, Relief F selected 28 features, which is 4 fewer than the number selected by RF_RFE and 22 fewer than those selected by CST. (2) The comparative analysis of the three feature selection algorithms indicated that the red-edge features B5, B6, and B7 were all integral to the classification process, underscoring their critical role in crop recognition. Additionally, the inclusion of bands B11 and B12, along with texture features, further enhanced the accuracy of crop recognition. Different feature selection algorithms exhibited varying preferences in feature selection; specifically, Relief F showed a tendency to favor spectral and index features. (3) A comparison of three different machine learning methods revealed that the combination of Relief F with Random Forest (RF) yielded the most accurate crop classification for the study area, while XGBoost and Support Vector Machine (SVM) demonstrated inferior performance. Under the conditions established by the Relief F feature selection, RF achieved an overall accuracy of 93.39%, a Kappa coefficient of 0.8933, and an F1 score of 94.31%. These results indicated that RF outperformed XGBoost and SVM by 1.36%, 0.021, and 1.31%, as well as by 8.81%, 0.1312, and 8.78%, respectively. This experiment strongly validates the effectiveness and advanced nature of combining the Relief F feature selection method with Random Forest classification. It demonstrates how optimizing feature selection and employing suitable machine learning methods can significantly enhance classification performance across various agricultural contexts. These findings contribute to the effective utilization of remote sensing technologies, improving agricultural monitoring and decision-making. By illustrating the relationship between feature selection methods and classification accuracy, this study provides a novel technical approach for precision agricultural recognition and classification.

       

    /

    返回文章
    返回