Matlab - Buscar primer pixel blanco en un borde

a=randi([0,1],5,5);

b=rot90(a);

[x,y]=ind2sub(size(b),find(b==1,1,'first'));

x=size(a,2)+1-x;

disp(x)

disp(y)

clear all

close all

im_rgb=imread('perfil.png');

umbral=graythresh(im_rgb);

Im_bin=im2bw(im_rgb,umbral);

bol=0;

for columna=1:size(Im_bin,2)

    for fila=1:size(Im_bin,1)

        if Im_bin(fila,columna)==1

         bol=1;

         break;

        end

    end

    if bol==1

        break;

    end

end

posicion=[fila, columna]

figure(1);

imshow(im_rgb)

hold on

plot(columna,fila,'*r')

 hold off

 figure(2)

 imshow(Im_bin)

hold on

plot(columna,fila,'*r')

 hold off

clear all

close all

im_rgb=imread('perfil.png');

umbral=graythresh(im_rgb);

Im_bin=im2bw(im_rgb,umbral);

bol=0;

for columna=1:size(Im_bin,2)

    for fila=1:size(Im_bin,1)

        if Im_bin(fila,columna)==1

         bol=1;

         break;

        end

    end

    if bol==1

        break;

    end

end

posicion=[fila, columna]

figure(1);

imshow(im_rgb)

hold on

plot(columna,fila,'*r')

 hold off

 figure(2)

 imshow(Im_bin)

hold on

plot(columna,fila,'*r')

 hold off

 im_rgb1=im_rgb(:,end:-1:1,:);

 umbral1=graythresh(im_rgb1);

Im_bin1=im2bw(im_rgb1,umbral1);

bol1=0;

for columna1=size(Im_bin1,2):-1:1

    for fila1=1:size(Im_bin1,1)

        if Im_bin1(fila1,columna1)==1

         bol1=1;

         break;

        end

    end

    if bol1==1

       break;

    end

end

posicion1=[fila1, columna1]

figure(3);

imshow(im_rgb1)

hold on

plot(columna1,fila1,'*r')

 hold off

figure(4);

imshow(Im_bin1)

hold on

plot(columna1,fila1,'*r')

 hold off