MATLAB: Improper assignment with rectangular empty matrix., how to solve

debugging skillsimproper assignment with rectangular empty matrix

hey everyone
please i am getting this error :
Improper assignment with rectangular empty matrix on this line :
midpoints1(k) = (leftEdge1 + rightEdge1)/2;
how can i solve that ? any help is appreciated, thanks
for k=700:800
   oneRow1 = binaryImage(k, :);
   leftEdge1 = find(oneRow1, 1, 'first');
   rightEdge1 = find(oneRow1, 1, 'last');
   hold on;
   midpoints1(k) = (leftEdge1 + rightEdge1)/2;
   plot(leftEdge1, k, 'rx','LineWidth',2);
   plot(rightEdge1, k, 'rx','LineWidth',2);
   plot(midpoints1(k), k, 'yx','LineWidth',2);
end
X1=(700:800);
midpoints1=midpoints1(midpoints1~=0);
new_x1 = linspace(500, 900);
coeffs1 = polyfit(X1, midpoints1, 1);
new_y1 = polyval(coeffs1, new_x1);
plot(new_y1,new_x1, '-','LineWidth',2);

Best Answer

In some rows, there are no 1's. When that happens, the results of find() are empty. You are trying to store the midpoint of that empty range into midpoints1(k), which requires a location which is a 1x1 value not a 0 x 0 value.
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