How to creat a sparse matrix?

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

Answer 1

[Youssef Khmou]

hi,

i think you have to transform your matrix from Unsigned integer 8 to double, try :

 G=sparse(im2double(a)); %  or   simply  double(a)

[jagannath mishra]

i am using it and it also give me outputs without error.thank you very much.

[Youssef Khmou]

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]

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]

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);