Time-frequency filtering-based autofocus

Authors:
Ran Tao;Wei Zhang;Yanlei Li
Affiliations:
School of Information and Electronics, Beijing Institute of Technology, Beijing 100081, PR China;School of Information and Electronics, Beijing Institute of Technology, Beijing 100081, PR China;School of Information and Electronics, Beijing Institute of Technology, Beijing 100081, PR China
Venue:
Signal Processing
Year:
2011

Citing 4
Cited 1

A short-time Fourier transform

Signal Processing
Auto-Wigner-Ville distribution via non-adaptive and adaptive signal decomposition

Signal Processing
Autofocusing of SAR images based on parameters estimated from the PHAF

Signal Processing
Short-time fractional fourier transform and its applications

IEEE Transactions on Signal Processing

Optimal design of Hermitian transform and vectors of both mask and window coefficients for denoising applications with both unknown noise characteristics and distortions

Signal Processing

Quantified Score

Hi-index	0.08

Visualization

Abstract

Autofocus is very important to the imaging of air-borne synthetic aperture radar (SAR). There have been many kinds of the autofocus technique, which could fall into two categories according to whether the phase error is approximated with a parametric model or not. On the condition that prominent points exist in the image, the non-parametric methods have superiority over the parametric ones in dealing with high-order phase errors due to their high precision and appropriate computational complexity. As will be shown in this paper, the signal-to-clutter ratio (SCR) plays a pivotal roll in this kind of autofocus. The time-frequency filtering is introduced because of its extraordinary performance in raising the SCR of time-variant signals. Since the main part of the phase error is quadratic, the short-time fractional Fourier domain (STFRFD) filtering is utilized, and then a novel autofocus method termed time-frequency filtering-based autofocus (TFFA) is proposed. Theoretical analysis and simulations show the validity of this approach.