How can I get image value and change value?

Hi.

I have an image file. I want to draw a filled inside black circle. Must use this command : img(sub2ind(size(img),y,x))=0;

I cannot filled circle. I can make black circle only. How can I filled the circle?

Please help me. Thank you.

Answer 1

[David Sanchez]

hold on your image,

to draw a circle centered at (2,3):

t=0:.1:2*pi;
r=1;
x_c = 2;
y_c = 3;
x = x_c - r*cos(t);
y = y_c - r*sin(t);
fill(x,y,'k')

[PJM]

Thank you for your answer, but I already know about that. I want to draw a filled circle using 'change image value' method.