MATLAB: Insert columns between successive columns of image?!

digital image processingImage Processing Toolboxinsert columns between successive columnswaveletWavelet Toolbox

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.

Best Answer

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
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