Edge-Directed Sub-Pixel Extraction and Still Image Super-Resolution

This paper proposes a novel edge-directed sub-pixel extraction method for still images. The basic idea is to decompose the mixed pixels present at the low spatial resolution images into four sub pixels using edge-directed models, thus to localize the mixed pixels in a smaller region. The pixels marked as edge pixels in low resolution images are mixture of different end-members with different spectral signature and a set of corresponding fractions, abundances. According to the linear spectrum mixing model, that is, the reflectance spectrum of a mixture is a systematic combination of the component reflectance spectra in the mixture and the systematic is basically linear, the sub-pixels can be extracted by quad-decomposition geometrically depend on the decomposition models directed by different edge-types in the 3 x 3 neighborhood centered on the mixed pixels. The algorithm can be used in image interpolation and image super-resolution construction. Super-resolution experiments demonstrate that the new algorithm substantially improves the subjective quality of the enlarged images over the conventional bilinear and bicubic interpolation.