Error with the creation of vectors

Dear colleagues,

I need to calculate the relation of mean intensity of exterior border of regions between mean intensity of inside of regions . This regions are identified in a labels matrix called L. The number of regions is num=47.

For this purpose, I put in Matlab the following sentences:

pborde=strel('disk',3); 

for k=1:num

M=zeros(1960,1960); Matriz with size equal to original matriz

M(L==k)=1;  %L is the label matriz with all regions of my image

pborde2(k)=imdilate(M,pborde);

Bext(k)=M-pborde2(k);  

Bext(k)=double(Bext(k));

p2ext(k)=regionprops(Bext(k),yb,'MeanIntensity'); 

vp2(k)=p2intr(k).MeanIntensity./p2ext(k).MeanIntensity;

end;

    p2= vp2';

But Matlab gives me the following mistake "In an assignment A(I) = B, the number of elements in B and A must be the same". It seem that doesn´t made the vector. But this mistake is produced also if I put only this sentence:

for k=1:num

M=zeros(1960,1960);

M(L==k)=1;

end

What is the problem?

Thank you very much in advance

Answer 1

[Walter Roberson]

You would get that error if size(L) is not the same as size(M) -- and if you want the two to be the same size for sure then use

M = zeros(size(L));

[Cristina]

Thank you very much dear Walter,

I put your indication but Matlab gives me the same mistake

pborde=strel('disk',3);

for k=1:num

M=zeros(size(L));

M(L==k)=1;

pborde2(k)=imdilate(M,pborde);

Bext(k)=M-pborde2(k);

Bext(k)=double(Bext(k));

p2ext(k)=regionprops(Bext(k),yb,'MeanIntensity');

vp2(k)=p2intr(k).MeanIntensity./p2ext(k).MeanIntensity;

end;

p2= vp2';

What could I change? Where is the mistake?

[bym]

what do you get when you do size(L) in the command window?

[bym]

how did you create L? was it L = bwlabel(bw,n)?

[Cristina]

Yes, but n=num and bw is the original images of 1960 x 1960 x 3 and L is 1960 x 1960.

[Walter Roberson]

What error message does MATLAB give?

[Cristina]

size(L) is 1960 x 1960

[Cristina]

The mistake is "In an assignment A(I) = B, the number of elements in B and A must be the same"

[Cristina]

I don´t understant this error, because L and M have the same size. What is teh problem? If you run theses sentences Do you have the same error?