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    地形校正与随机森林优化的火烧迹地提取方法

    A method for information extraction of burned areas based on terrain correction and random forest feature optimization

    • 摘要: 森林火灾对生态系统结构与功能造成严重破坏,火烧迹地作为火灾后尚未恢复的土地,承载着重要的灾后信息,对生态监测与修复具有重要意义。针对复杂地形条件下火烧迹地识别精度不足的问题,该文将引入C校正系数的太阳-冠层-传感器的校正模型(sun-canopy-sensor+C,SCS+C)地形校正与随机森林(random forest,RF)特征优化方法相结合,提出了一种高精度火烧迹地提取方法。基于GF-1宽幅相机卫星遥感影像(wide field view,WFV),融合纹理特征与光谱指数构建多维特征集,采用SCS+C地形校正并通过RF优化方法评估特征子集间的相对重要性,筛选最优特征组合以实现火烧迹地高效提取。结果表明: ①SCS+C地形校正显著削弱了阴影效应,避免了阴影区域误判为火烧迹地; ②RF优化方法保留贡献率较高的特征子集,剔除冗余特征,改善了火烧迹地提取时出现的错分和漏分现象,有效提升了模型的精度; ③地形校正与RF优化结合的方法在多个典型区域的提取精度(总体精度、用户精度和生产者精度)均超过91%; ④在辽宁省2019—2023年的火烧迹地提取中,各年度的总体分类精度为79.63%~83.87%,Kappa系数为0.503 9~0.806 2,总体分类精度的平均值为81.90%,Kappa系数平均为0.707 3,进一步验证了该方法在火烧迹地提取中的普适性、稳定性与高效性,为火灾后生态监测与环境修复提供了可靠的技术支撑。

       

      Abstract: Forest fires tend to cause severe damage to the structures and functions of ecosystems. Burned areas that have not yet fully recovered from fires carry crucial post-fire information, holding significant implications for ecological monitoring and restoration. To address the challenge of insufficient accuracy in burned area identification under complex terrain conditions, this study proposed a high-precision information extraction method for burned areas that integrates sun-canopy-sensor (SCS) + C (SCS+C) terrain correction with random forest (RF) feature optimization. Based on the wide-field-view (WFV) images from the GF-1 satellite, a multi-dimensional feature set was constructed by integrating texture features and spectral indices. Through SCS+C terrain correction and RF feature optimization, the relative importance of feature subsets was assessed to identify the optimal feature combination for efficient information extraction of burned areas. The results indicate that SCS+C terrain correction significantly mitigated the shadow effect, avoiding misclassifying shadow areas as burned areas. The RF feature optimization retained feature subsets with higher contributions and eliminated redundant features, mitigating misclassification and omissions in the information extraction and effectively enhancing the model accuracy. The combination of terrain correction and RF feature optimization yielded extraction accuracy (including overall accuracy, user accuracy, and producer accuracy) of greater than 91% across multiple typical regions. In the information extraction of burned areas from 2019 to 2023 in Liaoning Province, the proposed method yielded overall classification accuracies of individual years ranging from 79.63% to 83.87% (average: 81.90%), with Kappa coefficients varying between 0.503 9 and 0.806 2 (average: 0.707 3). These results further validate the universality, stability, and efficiency of the proposed method in the information extraction of burned areas. This study provides reliable technical support for post-fire ecological monitoring and restoration.

       

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