how to measure distance between points in X using interactive mouse

Hello

I have used edge function to detect the edge of a shape in matlab, now I want to create a GUI where as someone moves their mouse over the image it draws a horizontal line between the points and measures the distance in X between the points, then when the mouse is clicked saves the distance.

Is this possible?

James

Answer 1

[Thomas]

try the imdistline fucntion

http://www.mathworks.com/help/images/ref/imdistline.html

[James Webster]

Thank you for this, yes this gets the information but I was wondering is there a way to get it to trace the line with mouse movement, almost as though it snaps to the next point as you push your mouse up the screen

[Thomas]

try

 ii=imread('name_img.jpg');
 imshow(ii);
 h=ginput(2)           % click two point on image
 distance_betwn_mouse_clicks=pdist(h)

or

distance_betwn_mouse_clicks=sqrt((h(2)-h(1))^2+(h(4)-h(3))^2)

instead of imdistline

[Image Analyst]

I think you meant imshow() instead of imread() because the image must be displayed for you to click on it. I don't have distp (base MATLAB or Image Processing Toolbox). You can use hypot() in that case.

[Thomas]

Thanks Image analyst..

[emami.m]

Thanks Thomas.

It was great.

Answer 2

[Image Analyst]

Try imfreehand() if you want to trace an arbitrary path. It doesn't "snap" to the next point though, like Photoshop's magnetic lasoo.