Optics: measuring and testing – By dispersed light spectroscopy – Utilizing a spectrometer
Patent
1998-07-08
2000-01-04
Kim, Robert H.
Optics: measuring and testing
By dispersed light spectroscopy
Utilizing a spectrometer
356359, 342 25, G01B 902
Patent
active
060116250
ABSTRACT:
An improved method is provided for phase unwrapping in coherent imaging systems which use two complex images to form an interferogram. In the improved method, the interferogram of phase differences is divided into a relatively large plurality of transform blocks, wherein each transform block comprises a matrix of o.times.p data samples, with o and p=2.sup.n +1, and n being an integer greater than 2. Further, adjacent transform blocks are preferably defined to partially overlap. The wrapped phase values of adjacent data samples within each transform block are then compared and if the difference therebetween exceeds a predetermined value, the entire block of data samples may be discarded for further use. Data samples of the retained transform blocks are then unwrapped to obtain phase values via an unweighted, least-squares technique implemented by Fast Fourier Transform. Using a known height value corresponding with a single data sample, an integration constant can be determined for a corresponding first transform block. Path-following may then be used to determine an integration constant for the other retained transform blocks. The phase values and integration constants may then be employed to determine height values for the interferogram. The disclosed method yields enhanced accuracy with reduced computational burden.
REFERENCES:
patent: 5608405 (1997-03-01), Pritt
patent: 5659318 (1997-08-01), Madsen et al.
patent: 5680138 (1997-10-01), Pritt
Ghiglia, D., and Pritt, M., "Two-Dimensional Phase Unwrapping, Theory, Algorithms, and Software," 1998.
Jakowats, Charles V., Jr., Wahl, Daniel E., Eichel, Paul H., Thompson, Paul A., "Spotlight-Mode Synthetic Aperture Radar: A signal Processing Approach," 1996.
Ghiglia, D.C. and Romero, L.A., "Robust two-dimensional weighted and unweighted phase unwrapping that uses fast transforms and interactive methods," J. Optical Society of America, Jan. 1994, vol. 11, No. 1, pp. 107-117.
Goldstein, Richard M., Zebker, Howard A., Werner, Charles, L. "Satellite radar interferometry: Two-dimensional phase unwrapping," Radio Science, Jul.-Aug. 1998, vol. 23, No. 4, pp. 713-720.
Ghiglia, Dennis C., Romero, Louis A., "Direct phase estimation from phase differences using fast elliptic partial differential equation solvers," Optics Letters, Oct. 15, 1980, vol. 14, No. 20, pp. 1107-1109.
Pritt, Mark D., Shipman, Jerome S., "Least-Squares Two-Dimensional Phase Unwrapping Using FFT's," IEEE Transactions on Geoscience and Remote Sensing, May vol. 32, No. 3, 1994, pp. 706-708.
Hunt, B. R., "Matrix formulation of the reconstruction of phase values from phase differences," J. Optical Society of America, vol. 69, No. 3, Mar. 1979, pp. 393-399.
Pritt, Mark D., "Congruence in Least-Squares Phase Unwrapping," Lockheed-Martin Federal Systems, date unknown.
Zebker, Howard A., Werner, Charles L., Rosen, Paul A., Hensley, Scott; "Accuracy of Topographic Maps Derived from ERS-1 Interferometric Radar," IEEE Transactions on Geoscience and Remote Sensing, vol. 32, No. 4, Jul. 1994, pp. 823-836.
Pritt, Mark D., "Comparison of Path-Following and Least-Squares Phase Unwrapping Algorithms," Lockheed-Martin Federal Systems, date unknown.
Kim Robert H.
Lee Andrew H.
Lockheed Martin Corporation
LandOfFree
Method for phase unwrapping in imaging systems does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for phase unwrapping in imaging systems, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for phase unwrapping in imaging systems will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1077026