U-Fresh: An Fri-Based Single Image Super Resolution Algorithm and An Application in Image Compression
Xin Deng, Junjie Huang, Mengying Liu, Pier Luigi Dragotti · 2018
Learning based single image super resolution (SISR) methods have achieved notable results, however, they require large datasets for training, and may struggle when there is a mismatch between the testing and training data. To overcome these drawbacks, we propose an approach, named U - FRESH, which only requires a small dataset but can achieve state-of-the-art performance also in the presence of training and testing mismatches. We accomplish this by leveraging a method called FRESH, which enhances the image resolution using FRI theory. We start upscaling from the FRESH generated low resolution image. To minimize the reconstruction error, we propose a new regression selection technique to make the mapping more reliable and robust, and a wavelet based back projection technique to improve the quality of the reconstructed image. Based on U - FRESH, we also propose a new framework based on JPEG 2000 for image compression. Numerical results show that our U-FRESH method achieves state-of-the-art performance in SISR and provides better compression results than JPEG 2000.