Home To find mean of image using .PixelValues in regionprops using matlab
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To find mean of image using .PixelValues in regionprops using matlab

Silpa
1#
Silpa Published in 2018-02-13 05:10:45Z

I am trying to find out mean,kurtosis,skew etc of different connected regions seperately. May I found it using .PixelValue command using following code? or .PixelValue command to be used? Please help me.This is my first work.Please correct my code to find mean. % Out is my region of interest output image.

[val num]=bwlabel(Out);    
STATS=regionprops(val,'All');    
for i=1:num
   kk=STATS(i);    
   kk1=kk.PixelList;
   % To find mean
   [r c]=size(kk1);    
   ax(i)=r*c;   
   pp(i)=sum(sum(kk1));    
   bx(i)=pp(i)/su;
   mean=bx(i);
end
Cris Luengo
2#
Cris Luengo Reply to 2018-02-15 14:27:27Z

If you want to compute the mean of the pixel values of a within connected components of Out, then you want to do as follows (assuming a is a grey-value image):

lab = bwlabel(Out);
stats = regionprops(lab,a,'PixelValues');

and then, for each stats.PixelValues, compute the mean:

m = zeros(size(stats))
for ii = 1:numel(stats);    
     m(ii) = mean(stats(ii).PixelValues);
end

or more simply:

m = cellfun(@mean,{stats.PixelValues})

Note that regionprops can be called with a second input image, which contains the grey values. The 'PixelValues' property is a list with pixel values for each connected component.

To further simplify the code, you can skip calling bwlabel, and directly pass the binary image to regionprops:

stats = regionprops(Out,a,'PixelValues');
bla
3#
bla Reply to 2018-02-13 10:29:22Z

you can just do:

for i=1:numel(STATS);    
     ms(i)=mean(Out(STATS(i).PixelIdxList));
end

a few comments: PixelIdxList is the linear index of the array you want, so just one number, no need for x,y. read about it here . dont call mean as a variable name it's a built in function.

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