Guided image upsampling using bitmap tracing

Traditional upsampling methods apply spatial-invariant filtering across the entire image for efficiency, but often produce unsatisfactory artifacts around the edges. We propose a novel image upsampling algorithm that preserves the image structure, particularly around the edges, better than previous techniques. Our method computes a spline approximation to the edges in the image via bitmap tracing. A scaled version of the traced image is then used as a guide for joint bilateral up-sampling to produce the final result. Our method is easy to implement and the visual fidelity and quality of our results compare favorably to state-of-the-art techniques.