Lightweight single image super-resolution with attentive residual refinement network

The external example-driven single image super-resolution (SISR) method that uses a deep convolutional neural network (CNN) has exhibited superior performance as compared to previously developed SISR methods. However, the advantages of jointly using external and internal examples on a deep CNN framework have not been sufficiently investigated. In this letter, we present a novel method for single image super-resolution by exploiting a complementary relation between external and internal example-based SISR methods. The proposed deep CNN model consists of two subnetworks, a global residual network and a self-residual network, to utilize the advantages of both external and internal examples. In contrast with conventional joint SISR methods, the proposed method is the first deep CNN-based SISR method that does not require a retraining process, which tends to be inefficient. The proposed method outperformed existing methods in both quantitative and qualitative evaluations.

Lightweight image super-resolution with feature enhancement residual network

In recent years, single image super-resolution (SISR) methods using deep convolution neural network (CNN) have achieved impressive results. Thanks to the powerful representation capabilities of the deep networks, numerous previous ways can learn the complex non-linear mapping between low-resolution (LR) image patches and their high-resolution (HR) versions. However, excessive convolutions will limit the application of super-resolution technology in low computing power devices. Besides, super-resolution of any arbitrary scale factor is a critical issue in practical applications, which has not been well solved in the previous approaches. To address these issues, we propose a lightweight information multi-distillation network (IMDN) by constructing the cascaded information multi-distillation blocks (IMDB), which contains distillation and selective fusion parts. Specifically, the distillation module extracts hierarchical features step-by-step, and fusion module aggregates them according to the importance of candidate features, which is evaluated by the proposed contrast-aware channel attention mechanism. To process real images with any sizes, we develop an adaptive cropping strategy (ACS) to super-resolve block-wise image patches using the same well-trained model. Extensive experiments suggest that the proposed method performs favorably against the state-of-the-art SR algorithms in term of visual quality, memory footprint, and inference time. Code is available at \url{https://github.com/Zheng222/IMDN}.

Recent research on single image super-resolution (SISR) using convolutional neural networks (CNNs) with the utilization of residual structures and attention mechanisms to utilize image features has demonstrated excellent performance. However, previous SISR techniques mainly integrated extracted image features within a deep or wide network architecture, ignoring the interaction between multiscale features and the diversity of features. At the same time, SISR is also a typical ill-posed problem in that it allows for several predictions for a given LR image. These problems limit the great learning ability of CNNs. To solve these problems, we propose a closed-loop residual attention network (CLRAN) to extract and interact with all the available diversity of features features efficiently and limit the space of possible function solutions. Specifically, we design an enhanced residual attention block (ERA) to extract features, and it dynamically assigns weight to the internal attention branches. The ERA combines multi-scale block (MSB) and enhanced attention mechanism (EAM) base on the residual module. The MSB adaptively detects multiscale image features of different scales by using different 3 × 3 convolution kernels. The EAM combines multi-spectral channel attention (MSCA) and spatial attention (SA). Therefore, the EAM extracts different frequency component information and spatial information to utilize the diversity features. Furthermore, we apply the progressive network architecture and learn an additional map for model monitoring, which forms a closed-loop with the mapping already learned by the LR to HR function. Extensive experiments demonstrate that our CLRAN outperforms the state-of-the-art SISR methods on public datasets for both ×4 and ×8, proving its accuracy and visual perception.

MSAR-Net: Multi-scale attention based light-weight image super-resolution

Deep convolutional neural networks have been widely used in single image super-resolution (SISR) with great success. However, the performance and efficiency of such models need to be improved for practical applications. In this paper, a novel deep quantification down-plain-upsampling (QDPU) network for SISR is proposed. In the framework, a down-plain-upsampling (DPU) residual block based on U-Net is firstly designed to reduce the computational cost by transforming the spatial scale of feature maps without sacrificing the reconstruction performance. Then, to better transmit low-level features to the reconstruction layer, we construct quantification skip-connection modules to integrate the outputs of the DPU residual blocks. Finally, QDPU is developed by stacking the DPU residual blocks with multiple skip-connections to reconstruct high-resolution images and reduce the computational burden. Quantitative and qualitative evaluations of the reconstruction results on four benchmark datasets show that the proposed method can achieve better performance compared with several state-of-the-art SISR methods.

The study presents the results of the development and testing of deep learning neural network architectures, which demonstrate high accuracy rates in classifying neurophysiological data, in particular hemodynamic brain activation patterns obtained by functional near-infrared spectroscopy, during solving mathematical problems on spatial-numerical associations. The analyzed signal represents a multidimensional time series of oxyhemoglobin and deoxyhemoglobin dynamics. Taking the specificity of the fNIRS signal into account, a comparative analysis of 2 types of neural network architectures was carried out: (1) architectures based on recurrent neural networks: recurrent neural network with long short-term memory, recurrent neural network with long short-term memory with fully connected layers, bidirectional recurrent neural network with long short-term memory, convolutional recurrent neural network with long short-term memory; (2) architectures based on convolutional neural networks with 1D convolutions: convolutional neural network, fully convolutional neural network, residual neural network. Trained long short-term memory recurrent neural network architectures showed worse results in accuracy in comparison with 1D convolutional neural network architectures. Residual neural network (model_Resnet) demonstrated the highest accuracy rates in three experimental conditions more than 88% in detecting age-related differences in brain activation during spatial-numerical association tasks considering the individual characteristics of the respondents’ signal.

Recently, the deep convolutional neural network (CNN) has made remarkable progress in single image super resolution(SISR). However, blindly using the residual structure and dense structure to extract features from LR images, can cause the network to be bloated and difficult to train. To address these problems, we propose a simple and efficient distilling with residual network(DRN) for SISR. In detail, we propose residual distilling block(RDB) containing two branches, while one branch performs a residual operation and the other branch distills effective information. To further improve efficiency, we design residual distilling group(RDG) by stacking some RDBs and one long skip connection, which can effectively extract local features and fuse them with global features. These efficient features beneficially contribute to image reconstruction. Experiments on benchmark datasets demonstrate that our DRN is superior to the state-of-the-art methods, specifically has a better trade-off between performance and model size.

Agricultural machines (AMs) refer to equipment usually used in agriculture such as tractors, hand tools, and power tools. It reduces the labor work, increases farms produce, enhances goods quality, and reduces farming time and cost-saving. However, the faults in the fuel system, blades, engine of the AM will often result in degraded vehicle performance, compromising the vehicle’s efficiency and strength. To overcome these problems, fault detection algorithms are developed to identify the faults even before they occur with high classification accuracy. The deep convolutional neural network (DCNN) is a popular deep learning model that offers a high classification recognition rate, and it is widely adopted in similar fields for monitoring the health status of machines. Very few state-of-the-art works are available to identify the health state of agricultural machines using deep learning techniques and extracting the acoustic features from an audio recording. The acoustic signal-based agricultural machine health monitoring and fault prediction model using smartphones is a cost-effective option that is deployed in this proposed work. To optimize the network structure of the DCNN, this paper proposes a Levy flight optimization algorithm (LFOA). The DCNN-LFOA model is implemented on the smartphone’s on-board device (OBD) along with the health monitoring application. The LFOA algorithm minimizes the number of neurons in the DCNN hidden layer and the number of input features from the audio recordings and enhances the classification accuracy. The LFOA algorithm provides the optimal solution which is essential in developing a lightweight DCNN model to implement in the edge processor (smartphone). The experimental results prove that the proposed model gives improved accuracy for the six faults to be classified and serves as a new research model to identify the health condition of the vehicles.

Convolutional neural networks (CNNs) have recently made great progress in single image super-resolution (SISR) due to their powerful feature representation. However, most existing CNN-based SR methods mainly focus on designing deeper architectures to obtain superior representations, neglecting the global feature correlations inside networks, thus limiting the discriminative learning ability. In this paper, we propose a spatial graph convolutional network (SGCN) to amplify feature representation for high quality image rendering. Specifically, we present a residual feature refinement module (RFRM) in SGCN to encode correlations in both channel and spatial dimensions of features. A novel spatial graph attention (SGA) is deployed to model the correlations with awareness of global information for the feature enhancement. Further-more, we utilize the Gram matrix to infer the global relations in features, which adaptively measures the pixel-wise spatial attention with free parameters. Experimental results demonstrate the superiority of our SGCN over state-of-the-art SISR methods in terms of quantitative metrics and visual quality.

Recently deep convolutional neural network (CNN) has made significant achievement in Single Image Super-Resolution (SISR). Most CNN-based SISR methods used the default L2 norm of the error. However, for Hyperspectral Image (HSI), this loss function may bring spectral inconsistencies. The main reason is that most methods did not pay much attention to spectral loss. To HSI, the loss function should capture not only spatial information but also spectral consistency. In this paper, a Multi-Losses Function Network (MLFN) simultaneously considering spatial and spectral information is proposed, and is composed of two parts: one is Concatenate Dense Residual Network (CDRN), and the other is Loss Network (LN). CDRN is an image reconstruction network which can utilize the hierarchical features extracted from the low-resolution image. LN includes pixel-wise spatial loss and spectral loss which drive the learning of the entire reconstruction model. The experimental results prove that the proposed MLFN can enhance spatial resolution with the consistency of the spectrum of HSI preserved.

Potatoes are one of the most popular and widely consumed vegetable, yet their cultivation faces challenges due to diseases like Early and Late blight, causing significant yield losses. Timely and precise diagnosis of such diseases is critical for adopting effective mitigation approaches and maintaining food security. This research introduces a lightweight deep convolutional neural network for real time potato leaf disease classification. Trained on high-resolution images of healthy and diseased leaves, our optimized model balances accuracy and computational efficiency, making it suitable for resource-constrained devices. The key innovation of our approach lies in the design of an optimized convolutional neural network model, which significantly minimizes the number of trainable parameters by reducing model’s depth, and computational complexity while preserving high classification accuracy. With only 204,227 trainable parameters, it achieves 98.6% test accuracy, along with 98.9% training and 98.6% validation accuracy after 50 epochs . The model demonstrates high precision of 0.99 for early blight, 0.98 for late blight, and 1.00 for healthy potato leaves. A comparative analysis with established architectures like VGG-16, Alex Net, and ResNet-50 underscores the superiority of our approach in terms of performance and computational efficiency. The research provides a significant step forward in leveraging AI for precision agriculture, reducing the impact of potato diseases, and promoting global food security through the adoption of scalable and practical disease detection solutions.

Automatic recognition of surface defects for hot-rolled steel strip based on deep attention residual convolutional neural network

Predictive analysis on cellular traffic is important for the control and monitoring of wireless networks. Cellular traffic prediction is a challenging problem due to the non- stationarity and dynamic spatial-temporal correlation of the traffic. In this paper, we address the problem of accurate traffic prediction in a base station by proposing a deep neural network called RAConv. Its structure includes residual network, attention mechanism, and deep convolutional network. In the proposed architecture, a deep 3D residual convolutional network (ResConv3D) with three residual blocks are employed to learn the local spatial-temporal features. An attention-aided convolutional long short-term memory network (AConvLSTM) is then used to capture the long-term spatial-temporal dependencies. The use of the attention modules enable the network to focus on the most important spatial-temporal information. We evaluate the performance of the proposed RAConv network using a dataset provided by a Canadian wireless service provider. We consider the traffic prediction on two time scales (i.e., hourly and daily), which exhibit different spatial-temporal dependency patterns. Experimental results show that the proposed RAConv network can achieve accurate prediction under both time scales. Results also show that our proposed network provides a lower root-mean-square error (RMSE) than the conventional ConvLSTM baseline scheme.

The single image super resolution recovers missing high resolution details so as to reconstruct a high resolution image from a single low resolution image. This paper proposes a novel directionally adaptive, learning-based, single image super resolution method using multiple direction wavelet transform, called directionlets. Here, critically sampled directionlets are used to capture directional features effectively and to extract edge information along different directions from a set of available high resolution images. This information is used as the training set for super resolving a low resolution input image. The directionlet coefficients at finer scales of its high resolution image are learned locally from this training set and the inverse directionlet transform recovers the super resolved high resolution image. The simulation results showed that the proposed directionlet approach outperforms standard interpolation techniques like cubic spline interpolation as well as standard wavelet-based learning, both visually and in terms of the mean squared error (MSE) values. The SNR scores for cubic spline interpolation, wavelet and directionlet method are 13.6998 dB, 23.8324 dB and 30.8654 dB respectively for Barbara.