Single Satellite Imagery Superresolution Based on Hybrid Nonlocal Similarity Constrained Convolution Sparse Coding

Abstract

The traditional superresolution methods based on image patches often ignore the consistency between the overlapped patches, causing block effects in produced images. The convolutional sparse coding based superresolution method uses the translation invariance of the convolution filter to directly encode the entire image, maintaining consistency and good performance. In this article, we propose a novel approach to single-image superresolution reconstruction based on hybrid nonlocal similarity constrained convolution sparse coding. We first decompose the input image into a smooth part and a texture part. The Bayesian nonparametric model can use more prior information of the original image, so we replace the previous bicubic interpolation with this method to better reconstruct the residual high-frequency information in the smooth part. When reconstructing the texture part, this article proposes a nonlocal similarity constrained convolutional sparse coding method, which transforms the reconstruction of the texture part to minimize the convolution sparse coding noise of the feature maps and classifies the image patches in the search space by using the correlation coefficients as the structural information, avoiding unnecessary weight calculation. Several methods were tested on satellite images extensively. Both visual inspection and quantitative analysis results demonstrate that our method outperforms other state-of-the-art methods and increases noise immunity effectively.

Keywords

• Bayesian nonparametric model
• convolution sparse coding
• correlation coefficient
• nonlocal (NL) similarity structure
• superresolution (SR) reconstruction