Plot over an image

Hello, I am trying to place a plot over an image and is not working.

CODE: a=[xu,xl]; %start and end x coordinates of blue line

b=[yl,yr]; %start and end y coordinates of blue line

c=[xu,xl]; %start and end x coordinates of green line

d=[yr,yl]; %start and end y coordinates of green line

imshow(img), colormap jet

hold on

plot(a,b,'blue',c,d,'green')

hold off

Does anyone has any ideia of what's wrong?

Thanks!

Answer 1

[Joseph Cheng]

I would check your points. i see that b and d are swapped, but is there sufficient distances for you to see it with the image behind? are you sure that there isn't just a 1~2 pixel line somewhere or that start and end points are the same. you could be drawing a dot, or too small of a line to notice anything.

x = rand(500,500,3);
a=[0 500];
b = [0 500];
c = [500 0];
d = [250 0];
imshow(x),colormap jet
hold on
plot(a,b,'blue',c,d,'green')

works and draws the image and lines.

[turningpoint]

You are right! I was using the smaller version of the image(scatterbrain) Thanks a lot!