Hybrid Function Sparse Representation towards Image Super Resolution
This work addresses image super-resolution for applications requiring high-quality upscaling, but it is incremental as it builds on existing sparse representation techniques with a novel dictionary design.
The paper tackled image super-resolution by proposing a hybrid function sparse representation (HFSR) method that uses a dictionary generated from preset functions without training, achieving excellent performance on detailed images in the Set14 dataset compared to non-learning state-of-the-art methods.
Sparse representation with training-based dictionary has been shown successful on super resolution(SR) but still have some limitations. Based on the idea of making the magnification of function curve without losing its fidelity, we proposed a function based dictionary on sparse representation for super resolution, called hybrid function sparse representation (HFSR). The dictionary we designed is directly generated by preset hybrid functions without additional training, which can be scaled to any size as is required due to its scalable property. We mixed approximated Heaviside function (AHF), sine function and DCT function as the dictionary. Multi-scale refinement is then proposed to utilize the scalable property of the dictionary to improve the results. In addition, a reconstruct strategy is adopted to deal with the overlaps. The experiments on Set14 SR dataset show that our method has an excellent performance particularly with regards to images containing rich details and contexts compared with non-learning based state-of-the art methods.