value changes when running each time

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kash
kash on 5 Mar 2013
x=imread('im9.bmp');
HSV = rgb2hsv(x);
H = HSV(:,:,1); H = H(:);
S = HSV(:,:,2); S = S(:);
V = HSV(:,:,3); V = V(:);
idx = kmeans([H S V], 3,'distance','sqEuclidean');
tabulate(idx)
the percentage for each idx gets changed every time i run the program,whay i am getting like this,kindly assist
  3 Comments
kash
kash on 22 Mar 2013
I used
idx = kmeans(reshape(HSV, [], 3), 3,'distance','sqEuclidean');
even then i get same error each cluster changes and different color is applied each time
Walter Roberson
Walter Roberson on 22 Mar 2013
kmeans still uses random initialization when you use reshape(), unless you provide the starting centroids like I showed below.

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Answers (1)

Youssef  Khmou
Youssef Khmou on 5 Mar 2013
Edited: Youssef Khmou on 5 Mar 2013
hi kash,
i quote , from Wikipedia : " Commonly used initialization methods are Forgy and Random Partition" so each time you run the code : Random partition is the cause of that small change , so here is what you can do :
you run the code 10 times , each time you store that variable, it is then a R.V calculate its mean and STD , and conclude .
  9 Comments
Teja Muppirala
Teja Muppirala on 22 Mar 2013
Are you sure you have typed everything correctly?
x = imread('peppers.png');
HSV = rgb2hsv(x);
C=HSV(102:104,102:104);
idx = kmeans(reshape(HSV, [], 3),3,'distance','sqEuclidean','Start',C);
tabulate(idx)
For me, no matter how many times I run this, I always get the same result:
Value Count Percent
1 74013 37.64%
2 99481 50.60%
3 23114 11.76%
kash
kash on 22 Mar 2013
sorry the mistake i made was placed C inside single quotes,thanks

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