Re: Alternative to unwrap()

[Sepp Käsbauer]

Am Samstag, 17. Juli 2010 schrieb Børge Strand-Bergesen:

> I'm working with Fourier Transforms. In my application,
> discontinuities add a lot of problems. (I'm writing a program that
> compares the gain and delay responses of a computer generated filter
> to those preferred by a user.) I wouldn't know which journals to start
> reading to improve on unwrap().
>
> One idea I have been toying with is to add n*pi to the angle of each
> polar coordinate instead of n*2pi (for integer n). Whenever n is odd,
> I compensate by negating the absolute value. This "bipolar absolute"
> actually works very well, and I'm able to extract continuous phase and
> delay plots. Unfortunately, my method is a bit cumbersome and a far
> cry away from a one-size-fits-all. I need to be confident that the
> method works for a wide range of filters. Eventually it will have to
> be optimized for high-speed paralell execution.
>
> So any pointers to research on clever unwrap functions would be
> greatly appreciated.

Just a few pointers to documents. If you cant find them, drop me a note.

A New Recurrent Approach for Phase Unwrapping
                  Kattoush Abbas *
-------
A Simple and Reliable Phase
  Unwrapping Algorithm
        Eduard KRAJNIK
-------
Phase Unwrapping: A Review of Methods and a Novel Technique
                               Sam T. Kaplan*
             University of Alberta, Edmonton, AB, Canada
                            address@hidden
                                    and
                             Tadeusz J. Ulrych
         University of British Columbia, Vancouver, BC, Canada
-------
Computation of the One-Dimensional
       Unwrapped Phase
                by
         Zahi Nadim Karam
-------
PHASE UNWRAPPING ALGORITHMS IMPLEMENTED ON
           A SYMBIAN BASED MOBILE DEVICE
    Carol RUS, Lacrimioara GRAMA, Andrei DUSLEAG, Corneliu RUSU
--------
Exact Computation of the Unwrapped Phase of a Finite-Length Time Series
  David G. Long
--------

>
>
> Thanks,
> Borge

cu Sepp

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