Due to the unique feature of the three-dimensional convolution neural network, it is used in image classification. There are some problems such as noise, lack of labeled samples, the tendency to ...overfitting, a lack of extraction of spectral and spatial features, which has challenged the classification. Among the mentioned problems, the lack of experimental samples is the main problem that has been used to solve the methods in recent years. Among them, convolutional neural network-based algorithms have been proposed as a popular option for hyperspectral image analysis due to their ability to extract useful features and high performance. The traditional convolutional neural network (CNN) based methods mainly use the two-dimensional CNN for feature extraction, which makes the interband correlations of HSIs underutilized. The 3-D-CNN extracts the joint spectral-spatial information representation, but it depends on a more complex model. To address these issues, the report uses a 3-D fast learning block (depthwise separable convolution block and a fast convolution block) followed by a 2-D convolutional neural network was introduced to extract spectral-spatial features. Using a hybrid CNN reduces the complexity of the model compared to using 3-D-CNN alone and can also perform well against noise and a limited number of training samples. In addition, a series of optimization methods including batch normalization, dropout, exponential decay learning rate, and L2 regularization are adopted to alleviate the problem of overfitting and improve the classification results. To test the performance of this hybrid method, it is performed on the Salinas, University Pavia and Indian Pines datasets, and the results are compared with 2-D-CNN and 3-D-CNN deep learning models with the same number of layers.
The development of remote sensing images in recent years has made it possible to identify materials in inaccessible environments and study natural materials on a large scale. But hyperspectral images ...(HSIs) are a rich source of information with their unique features in various applications. However, several problems reduce the accuracy of HSI classification; for example, the extracted features are not effective, noise, the correlation of bands, and most importantly, the limited labeled samples. To improve accuracy in the case of limited training samples, we propose a multiscale dual-branch residual spectral-spatial network with attention to the HSI classification model named MDBRSSN in this article. First, due to the correlation and redundancy between HSI bands, a principal component analysis operation is applied to preprocess the raw HSI data. Then, in MDBRSSN, a dual-branch structure is designed to extract the useful spectral-spatial features of HSI. The advanced feature, multiscale abstract information extracted by the convolution neural network, is applied to image processing, which can improve complex hyperspectral data classification accuracy. In addition, the attention mechanisms applied separately to each branch enable MDBRSSN to optimize and refine the extracted feature maps. Such an MDBRSSN framework can learn and fuse deeper hierarchical spectral-spatial features with fewer training samples. The purpose of designing the MDBRSSN model is to have high classification accuracy compared to state-of-the-art methods when the training samples are limited, which is proved by the results of the experiments in this article on four datasets. In Salinas, Pavia University, Indian Pines, and Houston 2013, the proposed model obtained 99.64%, 98.93%, 98.17%, and 96.57% overall accuracy using only 1%, 1%, 5%, and 5% of labeled data for training, respectively, which are much better compared to the state-of-the-art methods.
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