1. In a computing environment, a method comprising: processing a lower-resolution image into a higher-resolution image, including by determining a gradient profile corresponding to the lower-resolution image, wherein the gradient profile is a one-dimensional profile along the gradient direction of the zero-crossing pixel; using a transform ratio and a gradient profile prior to transform the gradient profile into a high-resolution gradient profile, wherein the gradient profile prior is a parametric prior describing shape and sharpness of image gradients, and wherein the gradient profile prior is used to provide constraints on the image gradients in the high-resolution gradient profile; and reconstructing the higher-resolution image based upon the high-resolution gradient profile, wherein reconstructing the higher-resolution image includes minimizing an energy function by enforcing a gradient domain constraint shape and a reconstruction constraint, using the high-resolution gradient profile as the gradient domain constraint shape.