Communications: directive radio wave systems and devices (e.g. – Synthetic aperture radar
Patent
1997-07-09
2000-04-04
Lobo, Ian J.
Communications: directive radio wave systems and devices (e.g.,
Synthetic aperture radar
G01S 1390
Patent
active
060466952
ABSTRACT:
A SAR image auto-focus method uses statistics extracted from the image data to develop a phase pure hyperbolic correction function. The method processes an uncorrected azimuth line vector selected from an unfocused array into a corrected azimuth line vector. The method includes forming a bright spot list based on the selected uncorrected azimuth line vector where the bright spot list has at least one bright spot entry. Then, the uncorrected azimuth line vector is unpacked into an uncorrected segment set that has a first uncorrected segment corresponding to a first bright spot entry in the bright spot list. Then, the first uncorrected segment is processed into a first corrected segment based on an average phase slope corresponding to the first bright spot entry, the first corrected segment is packed into the corrected azimuth line vector, and the process repeated for all bright spots. The step of processing the first uncorrected segment into a first corrected segment includes processing the first uncorrected segment through a Fourier transform into an uncorrected spectrum vector, correcting the uncorrected spectrum vector to form a corrected spectrum vector, processing the corrected spectrum vector through an inverse Fourier transform into the first corrected segment. The step of correcting the uncorrected spectrum vector includes computing phase gradient .phi..sub.dot (f) at each frequency f in the uncorrected spectrum vector based on:
REFERENCES:
patent: 4924229 (1990-05-01), Eichel et al.
patent: 4999635 (1991-03-01), Niho
patent: 5189424 (1993-02-01), Brown
patent: 5260708 (1993-11-01), Auterman
patent: 5332999 (1994-07-01), Prati et al.
patent: 5394151 (1995-02-01), Knaell et al.
patent: 5424743 (1995-06-01), Ghiglia et al.
patent: 5448241 (1995-09-01), Zeoli et al.
patent: 5463397 (1995-10-01), Frankot
patent: 5552787 (1996-09-01), Schuler et al.
patent: 5608405 (1997-03-01), Pritt
patent: 5627543 (1997-05-01), Moreira
Dale A. Ausherman, et al. "Developments In Radar Imaging", IEEE Transactions On Aerospace And Electronic Systems, vol. AES-20, No. 4, Jul. 1984, pp. 363-400.
Mansfield Arthur W.
Poehler Paul L.
Lobo Ian J.
Science Application International Corporation
LandOfFree
Phase gradient auto-focus for SAR images does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Phase gradient auto-focus for SAR images, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Phase gradient auto-focus for SAR images will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-369540