1. A method for upscaling an image, comprising steps of upscaling the image by pixel interpolation to obtain a coarse upscaled image; and for each pixel of the coarse upscaled image, determining a nonlinear regression function for a patch of at least 3×3 pixels around a current pixel of the coarse upscaled image; and enhancing the value of the current pixel by adding the result of the nonlinear regression function, wherein a pixel of an upscaled image is obtained and wherein pixels adjacent to the current pixel are not modified.