准确及时地获取红树林物种的空间分布对于保护生态多样性至关重要。高光谱成像传感器被认为是监测红树林的有效工具。然而,红树林的空间复杂性和高光谱图像的光谱冗余对精细分类提出了挑战。此外,由于物种之间的光谱相似性,仅使用光谱信息对红树林物种进行精细分类是很困难的。为了解决这些问题,本研究提出了一种面向对象的多特征组合精细分类方法。具体来说,使用多尺度分割技术对高光谱图像进行分割,以获得不同种类的物体。然后,提取了各种特征,包括光谱,植被指数,分数阶微分,纹理,和几何特征,并采用遗传算法进行特征选择。此外,设计了十个特征组合方案来比较对红树林物种分类的影响。在分类算法方面,评估了四个机器学习分类器的分类能力,包括K最近邻(KNN),支持向量机(SVM),随机森林(RF),和人工神经网络(ANN)方法。结果表明,在单特征变量中,基于纹理特征的SVM分类精度最高,总体准确率为97.04%。在特征组合变量中,基于原始光谱的人工神经网络,一阶微分光谱,纹理特征,植被指数,几何特征达到了最高的分类精度,总体准确率为98.03%。纹理特征和分数阶微分被确定为重要变量,而植被指数和几何特征可以进一步提高分类精度。基于对象的分类,与基于像素的分类相比,可以避免盐和胡椒现象,并显着提高红树林物种分类的准确性和效率。总的来说,本研究提出的多特征组合方法和基于对象的分类策略为红树林物种的精细分类提供了强有力的技术支持,有望在红树林的恢复和管理中发挥重要作用。
Accurate and timely acquisition of the spatial distribution of
mangrove species is essential for conserving ecological diversity. Hyperspectral imaging sensors are recognized as effective tools for monitoring mangroves. However, the spatial complexity of
mangrove forests and the spectral redundancy of hyperspectral images pose challenges to fine classification. Moreover, finely classifying
mangrove species using only spectral information is difficult due to spectral similarities among species. To address these issues, this study proposes an object-oriented multi-feature combination method for fine classification. Specifically, hyperspectral images were segmented using multi-scale segmentation techniques to obtain different species of objects. Then, a variety of features were extracted, including spectral, vegetation indices, fractional order differential, texture, and geometric features, and a genetic algorithm was used for feature selection. Additionally, ten feature combination schemes were designed to compare the effects on
mangrove species classification. In terms of classification algorithms, the classification capabilities of four machine learning classifiers were evaluated, including K-nearest neighbor (KNN), support vector machines (SVM), random forests (RF), and artificial neural networks (ANN) methods. The results indicate that SVM based on texture features achieved the highest classification accuracy among single-feature variables, with an overall accuracy of 97.04%. Among feature combination variables, ANN based on raw spectra, first-order differential spectra, texture features, vegetation indices, and geometric features achieved the highest classification accuracy, with an overall accuracy of 98.03%. Texture features and fractional order differentiation are identified as important variables, while vegetation index and geometric features can further improve classification accuracy. Object-based classification, compared to pixel-based classification, can avoid the salt-and-pepper phenomenon and significantly enhance the accuracy and efficiency of mangrove species classification. Overall, the multi-feature combination method and object-based classification strategy proposed in this study provide strong technical support for the fine classification of mangrove species and are expected to play an important role in
mangrove restoration and management.