Accession Number:

ADA574493

Title:

Robust Global Image Registration Based on a Hybrid Algorithm Combining Fourier and Spatial Domain Techniques

Descriptive Note:

Corporate Author:

AIR FORCE RESEARCH LAB KIRTLAND AFB NM SPACE VEHICLES DIRECTORATE

Report Date:

2012-09-01

Pagination or Media Count:

15.0

Abstract:

A variety of image registration techniques have been investigated for applications such as image analysis, fusion compression, enhancement, and creating mosaics. In particular, robust registration is a key component of successful multi-frame processing aimed at super-resolution or high dynamic range imaging of space objects. Image registration techniques are broadly categorized as global area or feature-based, and can also be classified as being performed in either the Fourier or spatial image domain. Spatial domain methods are typically used for applications requiring accurate estimation of sub-pixel motion, such as multi-frame super-resolution based on dealiasing. However, these techniques often rely on the availability of a priori information good initial guess, and are therefore limited in terms of dynamic range of the global relative motions between camera and scene. A Gaussian pyramid approach is one standard method to extend the region of convergence of spatial domain techniques. On the other hand, Fourier domain-based correlation techniques such as the log-polar FFT L-P FFT method provide fast and reasonably accurate estimates of global shifts, rotation, and uniform scale change, and tend to perform well over a large range of frame-to-frame motion magnitudes. In this paper we begin to explore possible hybrid algorithms for robust global registration based on combining the L-P FFT and spatial domain techniques. Initial results are presented for a hybrid algorithm using the output of the L-P FFT method as an initial guess for a spatial domain technique. In addition, we explore the potential benefits of normalized gradient correlation NGC in performing the coarse L-P FFT registration. The use of NGC, as opposed to phase-only correlation, has recently been explored for improving performance of the L-P FFT method in terms of robustness and dynamic range of scale factor estimates. The results presented here are based on both simulated image sequences and

Subject Categories:

  • Optics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE