Understanding How Image Quality Affects Deep Neural Networks

Image quality is an important practical challenge that is often overlooked in the design of machine vision systems. Commonly, machine vision systems are trained and tested on high quality image datasets, yet in practical applications the input images can not be assumed to be of high quality. Recently, deep neural networks have obtained state-of-the-art performance on many machine vision tasks. In this paper we provide an evaluation of 4 state-of-the-art deep neural network models for image classification under quality distortions. We consider five types of quality distortions: blur, noise, contrast, JPEG, and JPEG2000 compression. We show that the existing networks are susceptible to these quality distortions, particularly to blur and noise. These results enable future work in developing deep neural networks that are more invariant to quality distortions.Comment: Final version will appear in IEEE Xplore in the Proceedings of the Conference on the Quality of Multimedia Experience (QoMEX), June 6-8, 201

Reconstruction Low- Resolution Image Face Using Restricted Boltzmann Machine

Low-resolution (LR) face images are one of the most challenging problems in face recognition (FR) systems. Due to the difficulty of finding the specific features of faces, the accuracy of face recognition is low. To solve this problem, some researchers are using an image reconstruction approach to improve the resolution of their images. In this research, we are trying to use the restricted Boltzmann machine (RBM) to solve the problem. Furthermore, a labelled face in the wild (lfw) database has been used to validate the proposed method. The results of the experiment show that the PSNR and SSIM of the image result are 34.05 dB and 96.8%, respectively

Effects of Degradations on Deep Neural Network Architectures

Recently, image classification methods based on capsules (groups of neurons) and a novel dynamic routing protocol are proposed. The methods show promising performances than the state-of-the-art CNN-based models in some of the existing datasets. However, the behavior of capsule-based models and CNN-based models are largely unknown in presence of noise. So it is important to study the performance of these models under various noises. In this paper, we demonstrate the effect of image degradations on deep neural network architectures for image classification task. We select six widely used CNN architectures to analyse their performances for image classification task on datasets of various distortions. Our work has three main contributions: 1) we observe the effects of degradations on different CNN models; 2) accordingly, we propose a network setup that can enhance the robustness of any CNN architecture for certain degradations, and 3) we propose a new capsule network that achieves high recognition accuracy. To the best of our knowledge, this is the first study on the performance of CapsuleNet (CapsNet) and other state-of-the-art CNN architectures under different types of image degradations. Also, our datasets and source code are available publicly to the researchers.Comment: Journa

Kernel Coupled Cross-Regression for Low-Resolution Face Recognition

Low resolution (LR) in face recognition (FR) surveillance applications will cause the problem of dimensional mismatch between LR image and its high-resolution (HR) template. In this paper, a novel method called kernel coupled cross-regression (KCCR) is proposed to deal with this problem. Instead of processing in the original observing space directly, KCCR projects LR and HR face images into a unified nonlinear embedding feature space using kernel coupled mappings and graph embedding. Spectral regression is further employed to improve the generalization performance and reduce the time complexity. Meanwhile, cross-regression is developed to fully utilize the HR embedding to increase the information of the LR space, thus to improve the recognition performance. Experiments on the FERET and CMU PIE face database show that KCCR outperforms the existing structure-based methods in terms of recognition rate as well as time complexity

Low-resolution facial expression recognition: A filter learning perspective

Abstract(#br)Automatic facial expression recognition has attracted increasing attention for a variety of applications. However, the problem of low-resolution generally causes the performance degradation of facial expression recognition methods under real-life environments. In this paper, we propose to perform low-resolution facial expression recognition from the filter learning perspective. More specifically, a novel image filter based subspace learning (IFSL) method is developed to derive an effective facial image representation. The proposed IFSL method mainly includes three steps: Firstly, we embed the image filter learning into the optimization process of linear discriminant analysis (LDA). By optimizing the cost function of LDA, a set of discriminative image filters (DIFs) corresponding to different facial expressions is learned. Secondly, the images filtered by the learned DIFs are added together to generate the combined images. Finally, a regression learning technique is leveraged for subspace learning, where an expression-aware transformation matrix is obtained using the combined images. Based on the transformation matrix, IFSL effectively removes irrelevant information while preserving useful information in the facial images. Experimental results on several facial expression datasets, including CK+, MMI, JAFFE, SFEW and RAF-DB, show the superior performance of the proposed IFSL method for low-resolution facial expression recognition, compared with several state-of-the-art methods