How to draw a line on an image in matlab?

Question

I have two points lets say:

• P(x,y) [point lies at the top of image]
• P\'(x\',y\') [point lies at bottom of image]

Now i want to draw a l

Answer 1

The simplest way to draw a line onto an image is to use PLOT.

%# read and display image
img = imread('autumn.tif');
figure,imshow(img)

%# make sure the image doesn't disappear if we plot something else
hold on

%# define points (in matrix coordinates)
p1 = [10,100];
p2 = [100,20];

%# plot the points.
%# Note that depending on the definition of the points,
%# you may have to swap x and y
plot([p1(2),p2(2)],[p1(1),p2(1)],'Color','r','LineWidth',2)

If you want a different color, either change the letter to any of rgbcmykw, or use RGB triplets (red is [1 0 0]). Have a look at the lineseries properties for more formatting options.