Super-Resolution for Synthetic Zooming

Abstract

Optical zooming is an important feature of imaging systems. In this paper, we investigate a low-cost signal processing alternative to optical zooming-synthetic zooming by super-resolution (SR) techniques. Synthetic zooming is achieved by registering a sequence of low-resolution (LR) images acquired at varying focal lengths and reconstructing the SR image at a larger focal length or increased spatial resolution. Under the assumptions of constant scene depth and zooming speed, we argue that the motion trajectories of all physical points are related to each other by a unique vanishing point and present a robust technique for estimating its 3D coordinate. Such a line-geometry-based registration is the foundation of SR for synthetic zooming. We address the issue of data inconsistency arising from the varying focal length of optical lens during the zooming process. To overcome the difficulty of data inconsistency, we propose a two-stage Delaunay-triangulation-based interpolation for fusing the LR image data. We also present a PDE-based nonlinear deblurring to accommodate the blindness and variation of sensor point spread functions. Simulation results with real-world images have verified the effectiveness of the proposed SR techniques for synthetic zooming.

Super-resolution: a comprehensive survey

“…- [129], [163], [244], [246], [448], [596] change the imaging model of Eq. (4) to include the effect of different zooming in the LR images.…”

Motion Blur and Deblur Through Green's Matrices

“…It is also known that depth discontinuities increase the complexity of the motion estimation process (Li, 2006).…”

Video super-resolution using motion compensation and classification-aided fusion

“…The method, however, exhibits enormous computational complexity. Li [2006] proposed an SR algorithm for the special case where a set of LR frames acquired at different focal lengths is available. Static SR methods, if directly applied to each video sequence frame, can not ensure the temporal consistency of the enlarged video, which impedes their direct application to video resolution enhancement.…”