how to perform integerr to integer wavelet transform on a image

2013 4 2
2 个回答
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更新时间：2017 11 17
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1 个投票

I have followed the steps in the lwr2 page of documentation but i hace error
My image size is 512 x 512
j=imread('F:\MAT WORK\COVER OBJECT\cranial scan.jpg');
>> haarint=liftwave('haar','int2int');
>> [cA cH cV cD]=lwt2(j,haarint);
??? Error using ==> plus
Integers can only be combined with integers of the same class, or scalar doubles.
Error in ==> lsupdate at 43 y = y + t(:,1:sx(2),:);
Error in ==> lwt2 at 106 case 'd' , H = H + lsupdate('r',L,liftFILT,DF,sH,LStype);

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HyperionZhou
HyperionZhou 2017-3-15
编辑：HyperionZhou 2017-3-15

2 个投票

Hi! I met the same problem. I found that data in image is uint8. And when we process lwt2, data must be double. Also, ' plus Integers can only be combined with integers of the same class, or scalar doubles.' shows that the problem lies in the type of data. So you just need to add these code:
j = double(j); [cA cH cV cD]=lwt2(j,haarint);
Also, cA, cH, cV, and cD are double. If you need process them in unsigned int, add this code:
cA = uint8(cA);
uint8() and double() won't change the data's value. However, if you try to use im2double, you will find that it changes. I am not sure about the reason, but I guess it just change the way to read the data instead keeping the value.

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alisha ahmad
alisha ahmad 2017-11-17
Dear HyperionZhou ! Thankyou so much for providing such a good explanation.It worked.

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Wayne King
Wayne King 2013-4-2

0 个投票

You should tell us more about your image. What is it's size and class?
Does the following work for you? It should.
liftscheme = liftwave('haar','int2int');
imdata = imread('ngc6543a.jpg');
[cA cH cV cD]=lwt2(imdata,liftscheme);

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Obuli Yuvaraj
Obuli Yuvaraj 2013-4-2
my image is a medical image It's class is uint8
Thank you for yur response sir
Obuli Yuvaraj
Obuli Yuvaraj 2013-4-2
I'm sorry Wayne
Your answer again provides the same bug
??? Error using ==> plus Integers can only be combined with integers of the same class, or scalar doubles.
Error in ==> lsupdate at 43 y = y + t(:,1:sx(2),:);
Error in ==> lwt2 at 106 case 'd' , H = H + lsupdate('r',L,liftFILT,DF,sH,LStype);
Inference: I don't understand what is cell type and whether it is of standard 3 x 3 array
My Objective: Transform the 512 x 512 medical image of uint8 class using the DWT (dwt2 matlab command). this results in double type co-efficients.But the images gets degraded after the transformation.In orrder to get the co-efficients in integer form i ought to use Integer wavelet transform.
Please do clarify...!

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