Maximum Likelihood Classifier

[ahmed]

hi
i am working on supervised classification of remotely sensed
images(3 band). i want to extract features like water,urban
areas,land and vegetation.

this can be done by maximum likelihood classification of the images
and finding the corresponding classes.

can anybody help me in the code for this or any thing helpful.

i shall be thankful.

[Bill]

What are you trying to do exactly?

[ahmed]

well i want to turn the satellite image into a thematic map of
different classes like "water,urban,forest,land" etc each represented
by a different color.

[Bill]

I have done that before. Which part of code you need?

This is the main formula after calculating the mean value and the
covariance for each training area.

for i2=1:number_of_classes;


g{i2} = double((-log(det(covariance{i2}))-(x-m{i2})))*inv
(covariance{i2})*(x-m{i2})';

end

Hope this helps

Bill

[ahmed]

thanks for the help Bill,

but can u tell me that how u computed the covariance for the RGB
image i.e when ROI(region of intrest) is supplied to the algorithm
then how it calculates the covariance and then the likelihood for
each class.

i mean the code snippet for mean,covariance,and then the
corresponding likelihood for that ROI.

[ahmed]

[Bill]

Have you got the ROI's ? If yes then for each area you can reshape
the area into nX3 matrix that represenet red,green and blue, for
eaxample:
for i=1:number_of_ROI;
red=ROI(i)(:,:,1);
green=ROI(i)(:,:,2);
blue =ROI(i)(:,:,3);
rgb=[reshape(red',[],1)reshape(green',[],1)reshape(blue',[],1)];
%to reshape the matrix into thrre columns(red,green,blue).
ROI_mean=mean(rgb);
ROI_Covariance=cov(rgb);
end

Try this it might solve your problem

[ahmed]

thanks a lot Bill, I really appericiate ur help.

[Bill]

What technique you use to get the ROI's?

[ahmed]

well i used the matlab function 'roipoly'

[ranjini]

can you send me the code of this project.
Bill <billu...@yahoo.com> wrote in message <ef03...@webx.raydaftYaTP>...

[bushra....@gmail.com]

[bushr...@cs.uol.edu.pk]

i also need code of maximum likelihood classification on landsat images in matlab. can you send me?

[m201...@gmail.com]

hello. I need the maximum likelihood classification code in matlab. can any one help me? I shal be thankful.