Author: a_valentino-guest Date: Tue Dec 28 10:35:30 2010 New Revision: 2565
URL: http://svn.debian.org/wsvn/blends/?sc=1&rev=2565 Log: Improved snaphu description Modified: projects/gis/trunk/debian-gis/tasks/sar Modified: projects/gis/trunk/debian-gis/tasks/sar URL: http://svn.debian.org/wsvn/blends/projects/gis/trunk/debian-gis/tasks/sar?rev=2565&op=diff ============================================================================== --- projects/gis/trunk/debian-gis/tasks/sar (original) +++ projects/gis/trunk/debian-gis/tasks/sar Tue Dec 28 10:35:30 2010 @@ -66,32 +66,35 @@ Responsible: Antonio Valentino <[email protected]> WNPP: 606882 Pkg-URL: http://bazaar.launchpad.net/~a.valentino/+junk/snaphu/files -Pkg-Description: Statistical-Cost, Netowrk-Flow Algorithm for Phase Unwrapping +Pkg-Description: Statistical-Cost, Netowrk-Flow Algorithm for 2D Phase Unwrapping Two-dimensional phase unwrapping is the process of recovering unambiguous phase data from a 2-D array of phase values known only modulo 2pi rad. . + There are many applications, like Magnetic Resonance Imaging (MRI), + Synthetic Aperture Radar (SAR), fringe pattern analysis, tomography + and spectroscopy, which as part of their fundamental operation depend + upon the extraction of a phase signal from their input image. Usually + the phase is available in a form that suffers from 2-pi phase jumps + due to the use of the mathematical arctangent function, which produces + an inherently wrapped output. This wrapped phase is unusable until the + phase discontinuities are removed. + . SNAPHU is an implementation of the Statistical-cost, Network-flow - Algorithm for Phase Unwrapping proposed by Chen and Zebker. This - algorithm poses phase unwrapping as a maximum a posteriori probability - (MAP) estimation problem, the objective of which is to compute the most - likely unwrapped solution given the observable input data. Because the - statistics relating the input data to the solution depend on the - measured quantity, SNAPHU incorporates three built-in statistical - models, for topography data, deformation data, and smooth generic data. - The posed optimization problem is solved approximately with use of - network-flow techniques. - . - SNAPHU always produces complete unwrapped solutions, and, in our tests, - its accuracy is comparable to or better than that of other available - algorithms. As SNAPHU uses an iterative optimization procedure, its - execution time depends on the difficulty of the interferogram. In - single-tile mode the required memory is on the order of 100 MB per - 1,000,000 pixels in the input interferogram. - . - The software is written in C and should run on most Unix/Linux - platforms. It is freely available to the public, subject to the - conditions outlined in the README file included with the distribution. + Algorithm for Phase Unwrapping particularly suitable for SAR + interferometry applications. This algorithm poses phase unwrapping as + a maximum a posteriori probability (MAP) estimation problem, the + objective of which is to compute the most likely unwrapped solution + given the observable input data. Because the statistics relating the + input data to the solution depend on the measured quantity, SNAPHU + incorporates three built-in statistical models, for topography data, + deformation data, and smooth generic data. The posed optimization + problem is solved approximately with use of network-flow techniques. + . + As SNAPHU uses an iterative optimization procedure, its execution time + depends on the difficulty of the interferogram. In single-tile mode + the required memory is on the order of 100 MB per 1,000,000 pixels in + the input interferogram. Depends: epr-api Homepage: http://github.com/bcdev/epr-api _______________________________________________ Blends-commit mailing list [email protected] http://lists.alioth.debian.org/mailman/listinfo/blends-commit
