insert columns between successive columns of image?!

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.

Answer 1

[Wayne King]

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

[Duaa]

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