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Hyperspectral image classification is a challenging problem for machine learning methods due to the small number of labelled samples and high spectral variability. In this paper, to solve this problem, a novel superpixel and multi-classifier fusion (SMCF)-based classification method for hyperspectral images is proposed. This method takes full advantage of the spectral information of superpixels and the spatial information of hyperspectral images and includes the following three steps. First, superpixels are used to increase the number of training samples and their spectral diversity. Second, label propagation (LP) is used to classify the hyperspectral images. Although LP is an efficient semi-supervised classification method, the corresponding performance is poor for certain land cover types with dispersed spatial distributions. Thus, a support vector machine (SVM) classifier is introduced to classify the hyperspectral images. Finally, the results of the SVM and LP classifiers are combined using our new class-specific weighted fusion algorithm. In the experiments, we selected three widely used and real hyperspectral data sets for evaluation. The final classification performance was evaluated based on two common metrics: the overall accuracy (OA) and the Kappa coefficient. The experimental results show that the proposed SMCF method is superior to six well-known classification methods, even when only 1% or less of the labelled samples are used. [ABSTRACT FROM AUTHOR]

Multiple kernel learning (MKL) is a popular and effective method for hyperspectral image classification. However, the communication and interaction among multiple basic kernels are insufficient among multiple basic kernels during the whole training process for traditional MKL methods. In this paper, a multiple kernel learning framework based on self-learning and mutual learning (MKML) is proposed. First, each basic kernel starts pretraining with its own training samples and then uses a trained model to make predictions. Second, the basic kernel selects some informative unlabeled samples with high entropy and queries other basic kernels for labeling. All basic kernels except the one that raised the problem negotiate together to determine the class label of the unlabeled samples. Third, the new pseudo-labeled samples are added to the initial training sample sets to train the model again. Finally, all basic kernels are combined to obtain excellent classification performance by the voting mechanism. The methodology is validated on three real hyperspectral images. The experimental results show that the proposed method exhibits better classification performance than well-known MKL methods. [ABSTRACT FROM AUTHOR]

Hyperspectral image classification methods may not achieve good performance when a limited number of training samples are provided. However, labeling sufficient samples of hyperspectral images to achieve adequate training is quite expensive and difficult. In this paper, we propose a novel sample pseudo-labeling method based on sparse representation (SRSPL) for hyperspectral image classification, in which sparse representation is used to select the purest samples to extend the training set. The proposed method consists of the following three steps. First, intrinsic image decomposition is used to obtain the reflectance components of hyperspectral images. Second, hyperspectral pixels are sparsely represented using an overcomplete dictionary composed of all training samples. Finally, information entropy is defined for the vectorized sparse representation, and then the pixels with low information entropy are selected as pseudo-labeled samples to augment the training set. The quality of the generated pseudo-labeled samples is evaluated based on classification accuracy, i.e., overall accuracy, average accuracy, and Kappa coefficient. Experimental results on four real hyperspectral data sets demonstrate excellent classification performance using the new added pseudo-labeled samples, which indicates that the generated samples are of high confidence. [ABSTRACT FROM AUTHOR]