Data 'xR' (#27) is inferred as a variable size matrix, while its specified type is something else ?

Hi There

The following function must give me tow output xR and yR from an image binary image type

function [xR,yR]=findXY(img)
accumulationVertical=sum(img,2);
accumulationHorizontal=sum(img,1);
x1=find(accumulationHorizontal>0,1,'first');
x2=find(accumulationHorizontal>0,1,'last');
y1=find(accumulationVertical>0,1,'first');
y2=find(accumulationVertical>0,1,'last');
xR=floor((x1+x2)/2);
yR=floor((y1+y2)/2);
width=x2-x1;
height=y2-y1;
end

I get the following error message

Data 'xR' (#27) is inferred as a variable size matrix, while its specified
type is something else?
and Data 'xR' (#27) is inferred as a variable size matrix, while its specified type is something else?

many thankans in advance.

Answer 1

[Walter Roberson]

find() with 'first' or 'last' can both return empty vectors. For example if the input image is all 0, then there is nothing to find in either vector and [] would be returned from the find(). Your outputs are therefor variable length, either [] or scalar.

Also, it is possible that Simulink does not know about the counts (1) and is assuming that find() is going to return an indefinitely long vector. If that is the case then accessing x1(1) instead of just x1, and likewise for the other variables, should do the trick. After you have corrected or the possibility of the matrix being all 0.

[bekhoukha mohammed]

this is simulink

[Walter Roberson]

Yes? And in Simulink, what does find(false,1,'first') return, a numeric index or [] ?

[bekhoukha mohammed]

yes, find is a numeric index ;

x1=find(accumulationHorizontal>0,1,'first');

accumulationHorizontal=sum(img,1); but accumulationHorizontal [];