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From: Wayne King on 2 May 2010 06:53
nasim <nasim.breeze112004(a)gmail.com> wrote in message <2065269218.54427.1272717879380.JavaMail.root(a)gallium.mathforum.org>...
> thanks for reply
> I have a 2D signal. I want get wt(x(t)) and wt(y(t)) (wavelet transform of signal) in dyadic scale level j(detail signal).
> how I use function dyad2 in wavelab ?
> does first input argument of this function is j in my problem?
> and is the output of this function is answer of my problem?
> if yes how I set type of wavelet(e.g haar)?
> how can I found help or example of using function of this toolbox?

Hi Nasim,

dyad2 (and the 1-D counterpart dyad) are used to find the indices in the wavelet transform which correspond to the coefficients of interest, not perform the wavelet transform. Your workflow in WaveLab should be:

1.) Use MakeONFilter to construct the wavelet filter
2.) Call FWT2_PO() to return the 2-D wavelet transform of your image.
3.) Use dyad2 to find the indices in the wavelet transform that correspond to the detail coefficients you are interested in: horizontal, vertical, or diagonal.
4.) Extract those indices from the wavelet transform returned in step 2.

If your image is 256X256, the "j" for the finest level detail coefficients is 7, which corresponds to 2^7 (one power of two down from 2^8x2^8). The next finest level is 6, and so on.

By the way, you really should consider using the Matlab Wavelet Toolbox, especially for processing images. I think that functionality handles 2-D and 3-D data much more naturally.

Hope that helps,
Wayne
From: nasim on 4 May 2010 07:32
thanks for reply, but i have some question again
1- when i use function fwt2_po() , i have this warning:
values other than 0 or 1 converted to logical 1. so all value of result is 1 or 0.

2- is it possible to get wavelet from coordinate of curve in 1D wavelet and using dyad instead of 2D ?
(i have image a curve(edge of shape) that represented with two array of coordinate of curve, is it possible to get wavelet transform of each array?
the length of array is not equal 2^j then i cant use function fwt_po().

3- i didn't understand the difference of level in argument fwt2_po() and dyad2(). if size of image was 2^7 and i get dyad level 4 then fwt2_po is 3 and dyad2 is 4???!! or this values is just dependent to size of image and is constant? (i want get 3 different level)

sorry for my question
regards
From: nasim on 6 May 2010 21:49
was my question very primitive?
can anyone guide me?
i need help for my project, plz help me
From: Wayne King on 7 May 2010 06:55
nasim <nasim.breeze112004(a)gmail.com> wrote in message <1359875746.86438.1273211396511.JavaMail.root(a)gallium.mathforum.org>...
> was my question very primitive?
> can anyone guide me?
> i need help for my project, plz help me

Hi Nasim, do you have the MATLAB Wavelet Toolbox?
From: nasim on 7 May 2010 04:37
yes but i don't know how choose scales and positions based on powers of two, i want dyadic scales and positions.
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