Image Super-Resolution Algorithm Based on an Improved Sparse Autoencoder

• Published in: Information (Basel) Vol. 9; no. 1; p. 11
• Main Authors: Huang, Detian, Huang, Weiqin, Yuan, Zhenguo, Lin, Yanming, Zhang, Jian, Zheng, Lixin
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.01.2018
• Subjects: Algorithms; Dictionaries; dictionary learning; Image acquisition; Image quality; Image resolution; Preprocessing; Redundancy; Regularization; sparse autoencoder; super-resolution; Training; Visual perception driven algorithms; Visual signals; ZCA whitening
• ISSN: 2078-2489; 2078-2489
• DOI: 10.3390/info9010011

Due to the limitations of the resolution of the imaging system and the influence of scene changes and other factors, sometimes only low-resolution images can be acquired, which cannot satisfy the practical application’s requirements. To improve the quality of low-resolution images, a novel super-resolution algorithm based on an improved sparse autoencoder is proposed. Firstly, in the training set preprocessing stage, the high- and low-resolution image training sets are constructed, respectively, by using high-frequency information of the training samples as the characterization, and then the zero-phase component analysis whitening technique is utilized to decorrelate the formed joint training set to reduce its redundancy. Secondly, a constructed sparse regularization term is added to the cost function of the traditional sparse autoencoder to further strengthen the sparseness constraint on the hidden layer. Finally, in the dictionary learning stage, the improved sparse autoencoder is adopted to achieve unsupervised dictionary learning to improve the accuracy and stability of the dictionary. Experimental results validate that the proposed algorithm outperforms the existing algorithms both in terms of the subjective visual perception and the objective evaluation indices, including the peak signal-to-noise ratio and the structural similarity measure.