[Blends-commit] r2565 - /projects/gis/trunk/debian-gis/tasks/sar

[a_valentino-guest at users.alioth.debian.org]

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 <antonio.valentino at tiscali.it>
 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