1. A super resolution (SR) system with database-free texture synthesis using a processor, the system comprising: an up-sampling unit configured to up-sample an input image, thereby resulting in an up-sampled image; an edge enhancement unit configured to enhance edges of the up-sampled image; a smooth region detection unit configured to determine whether the input image possesses a smooth region, wherein the edge enhancement unit is bypassed if the smooth region has been detected; a texture synthesis unit configured to take the input image as texture example to perform texture synthesis on the enhanced up-sampled image from the edge enhancement unit or on the unenhanced up-sampled image from the up-sampling unit, thereby resulting in a synthesized image; and a refinement unit configured to refine the synthesized image to restrict the synthesized image to be faithful to the input image; wherein the refinement unit applies reconstruction constraint to the synthesized image with an energy function: 
 E ( I h |I l )=| D ( I h *G )− I l | 2 where I l is the input image, I h is the up-sampled image, G is a Gaussian kernel and D is a down-sample process.