Antialiasing recovery

We present a method for restoring antialiased edges that are damaged by certain types of nonlinear image filters. This problem arises with many common operations such as intensity thresholding, tone mapping, gamma correction, histogram equalization, bilateral filters, unsharp masking, and certain nonphotorealistic filters. We present a simple algorithm that selectively adjusts the local gradients in affected regions of the filtered image so that they are consistent with those in the original image. Our algorithm is highly parallel and is therefore easily implemented on a GPU. Our prototype system can process up to 500 megapixels per second and we present results for a number of different image filters.