plotting 2 points

hey all !!! Can anyone please tell me the ways to plot points on the edge/boundary of an object from a segmented image.

i need to do further process with the result.

Answer 1

[David Young]

If you have the Image Processing Toolbox, have a look at the edge() function. The associated demos will give you examples that you can adapt to your problem.

[Aaditya]

i have image processing toolbox and i have tried it out.... the points has to be plotted over the detected edges automatically, without the need for specifying the x and y points... give me some ideas please

[David Young]

I am not sure what you mean by "without the need for specifying the x and y points". For more help, you'll have to explain more fully what you need to do.

[Aaditya]

My job is to plot points across the edges of the image and join pair of points to form chords. then some features of the chord( length, orientation and normalized normals) are binned to a k- dimensional histogram( chordiogram).

[David Young]

Plotting is a graphical operation, but making measurements of chords is not. It's hard to understand what your goal is.

All the same, the output of the edge function would still seem a good place to start. What is wrong with it? Have you looked at the demos?

Here's a simple example of plotting the edge points, to get you started:

>> imshow(im);

>> e = edge(im, 'canny');

>> [y, x] = find(e);

>> imshow(im);

>> hold on; plot(x, y, '.'); hold off;