How to creat a sparse matrix?

2013 5 18
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sir,i have an image and want to find out its "SPARSE-MATRIX".i have tried the code like S=sparse(a);where 'a' is my image.but i got an error like "Undefined function or method 'sparse' for input arguments of type 'uint8'."MY AIM IS JUST TO FIND OUT THE SPARSE MATRIX OF THE IMAGE.Thanks in advance

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Youssef Khmou
Youssef Khmou 2013-5-18

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hi,
i think you have to transform your matrix from Unsigned integer 8 to double, try :
G=sparse(im2double(a)); % or simply double(a)

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jagannath mishra
jagannath mishra 2013-5-19
i am using it and it also give me outputs without error.thank you very much.
Youssef Khmou
Youssef Khmou 2013-5-19
编辑：Youssef Khmou 2013-5-19
hi jagannath,
I think it works, here is an example using the picture 'circuit.tf' whose class is uint8 :
I=imread('circuit.tif');
G=sparse(im2double(I));
jagannath mishra
jagannath mishra 2013-5-20
编辑：jagannath mishra 2013-5-20
but sir the image while converting to double it lost data and becomes white .this is the url of my original image"http://tinypic.com/r/1hotvo/5"and after applying the double it will be like "http://tinypic.com/r/f57lg7/5".so i want to ask if i finding out its sparse is correct or is there any problem with my implimentation of program .
Youssef Khmou
Youssef Khmou 2013-5-20
the result you have is something else different, maybe you are applying binary transformation, try :
I=imread('test.jpg'); % where test.jpg is your sample
doubleI=im2double(I);
F=rgb2gray(doubleI);
G=sparse(F);

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