IEEE Trans Neural Netw Learn Syst. 2023 Jun;34(6):2753-2766. doi: 10.1109/TNNLS.2021.3107912. Epub 2023 Jun 1.
Neighborhood reconstruction is a good recipe to learn the local manifold structure. Representation-based discriminant analysis methods normally learn the reconstruction relationship between each sample and all the other samples. However, reconstruction graphs constructed in these methods have three limitations: 1) they cannot guarantee the local sparsity of reconstruction coefficients; 2) heterogeneous samples may own nonzero coefficients; and 3) they learn the manifold information prior to the process of dimensionality reduction. Due to the existence of noise and redundant features in the original space, the prelearned manifold structure may be inaccurate. Accordingly, the performance of dimensionality reduction would be affected. In this article, we propose a joint model to simultaneously learn the affinity relationship, reconstruction relationship, and projection matrix. In this model, we actively assign neighbors for each sample and learn the inter-reconstruction coefficients between each sample and their neighbors with the same label information in the process of dimensionality reduction. Specifically, a sparse constraint is employed to ensure the sparsity of neighbors and reconstruction coefficients. The whitening constraint is imposed on the projection matrix to remove the relevance between features. An iterative algorithm is proposed to solve this method. Extensive experiments on toy data and public datasets show the superiority of the proposed method.
邻里重建是学习局部流形结构的好方法。基于表示的判别分析方法通常学习每个样本与所有其他样本之间的重建关系。然而,这些方法构建的重建图有三个限制:1)它们不能保证重建系数的局部稀疏性;2)异类样本可能具有非零系数;3)它们在降维之前学习流形信息。由于原始空间中存在噪声和冗余特征,预先学习的流形结构可能不准确。因此,降维的性能会受到影响。在本文中,我们提出了一个联合模型,同时学习相似性关系、重建关系和投影矩阵。在这个模型中,我们主动为每个样本分配邻居,并在降维过程中学习每个样本与其具有相同标签信息的邻居之间的内部重建系数。具体来说,采用稀疏约束来确保邻居和重建系数的稀疏性。在投影矩阵上施加白化约束以去除特征之间的相关性。提出了一种迭代算法来求解该方法。在玩具数据和公共数据集上的大量实验表明了该方法的优越性。