Densely Connected Pyramidal Dilated Convolutional Network for Hyperspectral Image Classification

Recently, with the extensive application of deep learning techniques in the hyperspectral image (HSI) field, particularly convolutional neural network (CNN), the research of HSI classification has stepped into a new stage. To avoid the problem that the receptive field of naive convolution is small,...

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Main Authors: Feng Zhao, Junjie Zhang, Zhe Meng, Hanqiang Liu
Format: Article
Language:English
Published: MDPI AG 2021-08-01
Series:Remote Sensing
Subjects:
Online Access:https://www.mdpi.com/2072-4292/13/17/3396
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author Feng Zhao
Junjie Zhang
Zhe Meng
Hanqiang Liu
author_facet Feng Zhao
Junjie Zhang
Zhe Meng
Hanqiang Liu
author_sort Feng Zhao
collection DOAJ
description Recently, with the extensive application of deep learning techniques in the hyperspectral image (HSI) field, particularly convolutional neural network (CNN), the research of HSI classification has stepped into a new stage. To avoid the problem that the receptive field of naive convolution is small, the dilated convolution is introduced into the field of HSI classification. However, the dilated convolution usually generates blind spots in the receptive field, resulting in discontinuous spatial information obtained. In order to solve the above problem, a densely connected pyramidal dilated convolutional network (PDCNet) is proposed in this paper. Firstly, a pyramidal dilated convolutional (PDC) layer integrates different numbers of sub-dilated convolutional layers is proposed, where the dilated factor of the sub-dilated convolution increases exponentially, achieving multi-sacle receptive fields. Secondly, the number of sub-dilated convolutional layers increases in a pyramidal pattern with the depth of the network, thereby capturing more comprehensive hyperspectral information in the receptive field. Furthermore, a feature fusion mechanism combining pixel-by-pixel addition and channel stacking is adopted to extract more abstract spectral–spatial features. Finally, in order to reuse the features of the previous layers more effectively, dense connections are applied in densely pyramidal dilated convolutional (DPDC) blocks. Experiments on three well-known HSI datasets indicate that PDCNet proposed in this paper has good classification performance compared with other popular models.
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spelling doaj.art-651eeba60a2a4a129d01f50c10221f872023-11-22T11:08:16ZengMDPI AGRemote Sensing2072-42922021-08-011317339610.3390/rs13173396Densely Connected Pyramidal Dilated Convolutional Network for Hyperspectral Image ClassificationFeng Zhao0Junjie Zhang1Zhe Meng2Hanqiang Liu3School of Communications and Information Engineering (School of Artificial Intelligence), Xi’an University of Posts and Telecommunications, Xi’an 710121, ChinaSchool of Communications and Information Engineering (School of Artificial Intelligence), Xi’an University of Posts and Telecommunications, Xi’an 710121, ChinaSchool of Communications and Information Engineering (School of Artificial Intelligence), Xi’an University of Posts and Telecommunications, Xi’an 710121, ChinaSchool of Computer Science, Shaanxi Normal University, Xi’an 710119, ChinaRecently, with the extensive application of deep learning techniques in the hyperspectral image (HSI) field, particularly convolutional neural network (CNN), the research of HSI classification has stepped into a new stage. To avoid the problem that the receptive field of naive convolution is small, the dilated convolution is introduced into the field of HSI classification. However, the dilated convolution usually generates blind spots in the receptive field, resulting in discontinuous spatial information obtained. In order to solve the above problem, a densely connected pyramidal dilated convolutional network (PDCNet) is proposed in this paper. Firstly, a pyramidal dilated convolutional (PDC) layer integrates different numbers of sub-dilated convolutional layers is proposed, where the dilated factor of the sub-dilated convolution increases exponentially, achieving multi-sacle receptive fields. Secondly, the number of sub-dilated convolutional layers increases in a pyramidal pattern with the depth of the network, thereby capturing more comprehensive hyperspectral information in the receptive field. Furthermore, a feature fusion mechanism combining pixel-by-pixel addition and channel stacking is adopted to extract more abstract spectral–spatial features. Finally, in order to reuse the features of the previous layers more effectively, dense connections are applied in densely pyramidal dilated convolutional (DPDC) blocks. Experiments on three well-known HSI datasets indicate that PDCNet proposed in this paper has good classification performance compared with other popular models.https://www.mdpi.com/2072-4292/13/17/3396hyperspectral image classificationconvolutional neural networkdilated convolutiondense connection
spellingShingle Feng Zhao
Junjie Zhang
Zhe Meng
Hanqiang Liu
Densely Connected Pyramidal Dilated Convolutional Network for Hyperspectral Image Classification
Remote Sensing
hyperspectral image classification
convolutional neural network
dilated convolution
dense connection
title Densely Connected Pyramidal Dilated Convolutional Network for Hyperspectral Image Classification
title_full Densely Connected Pyramidal Dilated Convolutional Network for Hyperspectral Image Classification
title_fullStr Densely Connected Pyramidal Dilated Convolutional Network for Hyperspectral Image Classification
title_full_unstemmed Densely Connected Pyramidal Dilated Convolutional Network for Hyperspectral Image Classification
title_short Densely Connected Pyramidal Dilated Convolutional Network for Hyperspectral Image Classification
title_sort densely connected pyramidal dilated convolutional network for hyperspectral image classification
topic hyperspectral image classification
convolutional neural network
dilated convolution
dense connection
url https://www.mdpi.com/2072-4292/13/17/3396
work_keys_str_mv AT fengzhao denselyconnectedpyramidaldilatedconvolutionalnetworkforhyperspectralimageclassification
AT junjiezhang denselyconnectedpyramidaldilatedconvolutionalnetworkforhyperspectralimageclassification
AT zhemeng denselyconnectedpyramidaldilatedconvolutionalnetworkforhyperspectralimageclassification
AT hanqiangliu denselyconnectedpyramidaldilatedconvolutionalnetworkforhyperspectralimageclassification