In addition to the algorithms listed here, there are lots of filters used for image upsampling that optimize for specific qualities. For example, the bilateral filter can preserve sharp edges and smooth out everything else so that the blur artifacts that arise from e.g. bilinear interpolation are less apparent.
In addition to the algorithms listed here, there are lots of filters used for image upsampling that optimize for specific qualities. For example, the bilateral filter can preserve sharp edges and smooth out everything else so that the blur artifacts that arise from e.g. bilinear interpolation are less apparent.