Image Zooming by Curvature Interpolation and Iterative Refinement
Young-Joon Cha, Gi Yun Lee, Seongjai Kim · SIAM Journal on Imaging Sciences · 2014
This article is concerned with an effective PDE-based image zooming method which is an improvement of the so-called curvature interpolation method (CIM) previously developed in [H. Kim, Y. Cha, and S. Kim, IEEE Trans. Image Process., 20 (2011), pp. 1895--1903]. The new algorithm incorporates an iterative application of the CIM in order to be an interpolator and to construct a reliable image surface utilizing a generalized curvature source term estimated from the low resolution image. It also employs an effective 9-point scheme for the curvature evaluation which in turn makes the constructed image surface involve no observable ringing artifacts. It has been experimentally verified that the new method results in a high resolution image of clear and sharp edges and cloudless textures, showing qualities of superresolution. Its convergence is analyzed; various results are given to show effectiveness and reliability of the new method. The proposed method has proved not only superior to state-of-the-art methods in image quality but also sufficiently efficient to be applicable for real-time image zooming of arbitrary magnification factors.