[S.Area] not supported for code generation

hey guides i use this function on the simulink but show the error:Referencing a component from array of non-scalar values is not supported for code generation.

Function 'MATLAB Function' (#35.204.212), line 8, column 25:
"[S.Area]"
Launch diagnostic report.

what can replace this to success simulation on simulink.

function y = areaimg(u)
bw2 = zeros(240,320);
ss = 20; 
B = 6000;
img_bw2 = bwareaopen(u,ss,8);
[L2,num2]=bwlabel(img_bw2,8);
S = regionprops(L2,'Area');
bw2 = ismember(L2, find([S.Area] < B)); 
y = bw2;
end

Answer 1

[Walter Roberson]

Just loop. You are generating code anyhow, so the loop should be efficient.

Have you considered using bwareafilt() instead ?

[tsai kai shung]

but The function 'bwareafilt' is not supported for standalone code generation.

[Walter Roberson]

Ah. Well, loop then.

[tsai kai shung]

how to loop then?

[Walter Roberson]

bw2 = false(size(L2));
for K = 1 : num2
  if S(K).Area >= B
    bw2( L2 == K) = true;
  end
end

[tsai kai shung]

thanks for your help. by the way the false(size(L2))=zeros(size(L2))?

[Walter Roberson]

false() and zeros() are not the same: false() creates an array of type logical and zeros() creates an array of type double.

Answer 2

[Image Analyst]

What is num2? Is it 0, and therefore S is empty? If S is empty, then trying to access S.Area would throw an error.

Answer 3

[Image Analyst]

The whole function can be done with this single line of code

y = bwareafilt(u, [1, 6000]);

[tsai kai shung]

but this function not use on the simulink

[tsai kai shung]

what function can replace?