Understanding Hanning Window

[NBS]

Hello Daniel

I got the answer.

thank you.

Bye.

[imshakir86]

hello @kudos

i have no info of 1/4th vertical and horizantal hanning window can you help me what is meant by them in this regard.....

[NIquist]

There is no "Kudos".  That is just a forum method for saying thank you to other posters that help you.

There is also no "1/4 Hanning window".  Here is some Wiki info on Window Functions in general. http://en.wikipedia.org/wiki/Window_function

[imshakir86]

thanx for correction .......... i read the wiki link but i am still confused about how to apply a horizantal and vertical window on say a 64X256 matrix...........what should be its width in order to get a weighted average of the data.

[NIquist]

http://zone.ni.com/reference/en-XX/help/371361B-01/lvanlsconcepts/char_smoothing_windows/

http://zone.ni.com/devzone/cda/tut/p/id/4278

A 64x256 matrix of what?  Windowing is frequency-based and is generally used for spectral analysis, etc.   Is your matrix a picture or something?  Are you sure you're not really needing a convolution?  (see the example National Instruments\LabVIEW 8.5\examples\analysis\dspxmpl.llb\Edge Detection with 2D Convolution.vi)

It would be best if you posted what your application is and what you're trying to accomplish with LabVIEW.  There may be people on the boards here who have already done something similar.  More information means better help around here.

[imshakir86]

thanx for rhe reply.................

as for as my application is concerned i am actually applying hanning window in feature extraction for iris recognition.......i am applying this window for obtaining weighted average of an iris normalized (patched extracted) image before applying the discrete cosine transform........

plz help me how to proceed, any code fragment or idea will highly be appreciated.......

[NIquist]

That is a very interesting application.  There are many ways to enhance these types of images.  Filtering, windowing, edge detection, convolution, wavelets, etc.  Unfortunately, I can't give you very much help since most of the math is above my level.  Perhaps there are some math wizards around that can give you more help.  You may also want to try posting on the NI-Vision forum.

Do you have any NI-Vision software?  There are built-in functions for enhancing and quantifying video images.

I did a Google search on 'iris recognition hanning window convolution' and found many technical documents are available.  Most of these white papers are very advanced and you have to buy them so it's up to you if you want to invest your time and money in them.

[NIquist]

BTW, you've jumped on to an old thread that is marked SOLVED.  Most people here won't even bother reading this.  You should start a new thread explaining your specific problem.

[imshakir86]

ok many thanks to all of you.............