Patch and square detector program

Hello good afternoon I hope you can help me with this

I want to detect taches and squares using matlab vision, but the square is not detected yet.

Can someone support me with that?

clear all;
close all;
clc;

%Parametros de configuracion de la camara
cam=ipcam('http://192.168.68.102:8080/videofeed')
preview(cam)
%pause(5)

%Tomamos foto
E     = snapshot(cam);


EG   = rgb2gray(E);
EGF  = medfilt2(EG);

BW  = im2bw(EGF); 
BW1 = edge(EGF,'sobel'); 
BW2 = edge(EGF,'canny'); 

stats = regionprops(BW,'Perimeter','Area','Centroid','BoundingBox');

figure(1);
imshow (BW);

%Deteccion de formas
hold on 
for k=1: length(stats)
     thisboundingbox=stats(k).BoundingBox;
     if stats(k).Area <0
         rectangle('Position',[thisboundingbox(1),thisboundingbox(2),thisboundingbox(3),thisboundingbox(4)], 'EdgeColor', 'b','LineWidth',2);
     else
          rectangle('Position',[thisboundingbox(1),thisboundingbox(2),thisboundingbox(3),thisboundingbox(4)], 'EdgeColor', 'r','LineWidth',2);
     end
     
     if stats(k).Perimeter^2/stats(k).Area < 15
         text(stats(k).Centroid(1),stats(k).Centroid(2), '*  Ciculo','Color', 'r');
    
    
     end
end
pause (10) 


 %Mostramos imagen
 figure(2)
 subplot(1,3,1); imshow(E);
 title('Imagen Original');
 subplot(1,3,2); imshow(BW);
 title('Imagen blanco y negro');
 %subplot(1,3,3); imshow(BW1);
 %title('Contornos de las figuras');
 subplot(1,3,3); imshow(BW2);
 title('Contono suaves');
 
 clear all