WENO based adaptive image zooming algorithm

Zooming or upsampling images is a common technique and an essential step in many image processing algorithms. This process introduces new information that can lead to numerical effects such as ringing artifacts, aliasing effects and blurring of the image. In this paper, we propose a polynomial interpolation algorithm based on the WENO algorithm for upsampling images, which provides high accuracy in smooth regions, preserves edges and reduces aliasing effects. Although this is not the first application of WENO interpolation for image resampling, it is designed to have comparable complexity and memory load with better image quality than the separable WENO algorithm.

We show that the algorithm performs equally well on smooth functions, artificial pixel art and real digital images. The comparison with similar methods on test images shows good results on standard metrics and also provides visually satisfying results. Furthermore, the low complexity of the algorithm is ensured by a small local approximation stencil and the appropriate choice of smoothness indicators.