基于特征空间增强下空谱全变差非负矩阵分解的高光谱解混
Hyperspectral unmixing based on spectral-spatial total variation nonnegative matrix factorization with feature space augmentation
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摘要: 非负矩阵分解(nonnegative matrix factorization,NMF)因其良好的可解释性和易计算性被广泛用于高光谱影像(hyperspectral image,HSI)解混中。为了有效处理HSI中噪声和解混效率问题,该文提出了一种在特征空间增强下的空谱全变差NMF高光谱解混方法(spectral-spatial total variation nonnegative matrix factorization,SSTVNMF)。首先,通过特征提取,将原始数据空间转换到特征空间,在特征空间下进行解混处理,提高解混效率; 其次,为了降低噪声影响,利用双边滤波(bilateral filtering,BF)方法提取空间信息,对特征提取过程进行增强,保证所提取特征的准确性; 最后,为了保证解混方法的性能,基于NMF方法建立顾及空间特征和光谱特征的全变差(total variation,TV)正则化,空间TV通过计算相邻像元之间丰度的水平和垂直差异来促进丰度平滑,光谱TV是基于最小体积TV通过施加端元之间的约束力使体积最小化来增强端元提取。采用美国地质调查局光谱库合成数据作为模拟数据,Jasper Ridge数据集、APEX数据集和Cuprite数据集作为真实数据进行验证,实验结果表明,相比较于其他基于NMF改进的方法,所提方法在定性和定量评价方面都有提高。Abstract: Nonnegative matrix factorization (NMF) is commonly used in hyperspectral image (HSI) unmixing due to its high interpretability and computability. To effectively address HSI noise and improve unmixing efficiency, this study proposed a method for hyperspectral unmixing based on spectral-spatial total variation nonnegative matrix factorization (SSTVNMF) with feature space augmentation. First, the original data space was converted to the feature space through feature extraction, allowing the unmixing process to be performed in the feature space for enhanced unmixing efficiency. Second, to reduce the impact of noise, the spatial information was extracted using the bilateral filtering (BF) method for enhanced feature extraction, thereby ensuring the accuracy of extracted features. Third, to ensure the effectiveness of the unmixing method, total variation (TV) regularization that considers both spatial and spectral features was established based on the NMF method. The spatial TV promotes abundance smoothing by calculating the horizontal and vertical differences in abundance between neighboring pixels. Based on the minimum-volume TV, the spectral TV enhances endmember extraction by applying constraint forces between endmembers to minimize the volume. Finally, the proposed method was verified using the synthetic data from the USGS spectral library as simulated data and the Jasper Ridge, APEX, and Cuprite datasets as actual data. The experimental results demonstrate that the proposed method outperformed other improved NMF-based methods in terms of qualitative and quantitative assessments.
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