insert columns between successive columns of image?!

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Duaa
Duaa le 24 Sep 2011
Hello
I am working on algorithm for texture analysis project. I got to a point and very much stuck in it. what I did was reading an image and decompose it into 4 bands with haar wavelet filter, then I am stuck.. I want to insert columns of zeros between successive columns of the images, convolve the rows with the corresponding 1-D haar filter, insert rows of zeros between rows of the resulting image, and convolve the columns with another 1-D haar filter..
In wavelet toolbox there is a command line for extending an image let us assume we have the following matrix
x=[1 2 3;4 5 6;7 8 9]
% to extend I used
%Y = wextend(TYPE,MODE,X,L,LOC)
y= wextend('ac','zpd',x,2)
y =
0 0 1 2 3 0 0
0 0 4 5 6 0 0
0 0 7 8 9 0 0
you can see clearly the extension was in edges. I read the tutorial MathWorks for this command can you illustrate it much more? can I control the extension location to be between successive columns or rows? if it doesn't work is there other way to solve this problem?
please help me and thank you.

Réponse acceptée

Wayne King
Wayne King le 24 Sep 2011
Hi, You can use the Wavelet Toolbox function dyadup
x = [1 2; 3 4];
y = dyadup(x,'r');
z = dyadup(x,'c');
A = dyadup(x,1,'r');
B = dyadup(x,2,'r');
However, essentially what you are doing is already done in the inverse 2-D DWT. Just out of curiousity, why are you not just using the full powerful machinery of the Wavelet Toolbox? (idwt2, waverec2)
Wayne
  1 commentaire
Duaa
Duaa le 24 Sep 2011
firstly I want to thank you for your great answer.
hmm my problem is I am new to wavelet analysis I only read one book
and in fact it is not a book it is more likely a tutorial
"Wavelet toolbox for use with matlab"
If you read the book it doesn't illustrate what happens it reconstruction phase..
so I want to ask you sir maybe to you it would be silly but to me it's very helpful
if I use "waverec2" I will end up with
obtaining a new image with four times the pixels in the input image.
I mean the synthesize image will have twice resolution of the input image??
and please can you guide me to a good book of wavelet with images
again thank you

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