Selecting a row of image pixels as ROI from GUI

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Philip
Philip on 27 Feb 2011
Hello,
Does anyone know of a way to use GUIDE to allow a user to select a 1-dimensional row (vector) of pixels in an image as a region of interest (i.e. the straight edge of an object)? I have an edge detected (logical) version of the colour image, and want to use the user's selection to find the closest edge coordinates that correspond to that image.
Many thanks in advance for any help you can throw my way.

Accepted Answer

Paulo Silva
Paulo Silva on 27 Feb 2011
Make a GUI with pushbutton and axis
Display the image on that axis
The button callback will be something like this
[x,y,button]=ginput(number)
This will allow you to get the coordinates of the pixels, x is a vector with the vertical positions and y is a vector with the horizontal positions, number is the number of points you let the user mark on the picture.
If you want the user to decide how many points he wants do something like this
button=1;xx=[];yy=[];
while button==1
[x,y,button]=ginput(1);
plot(x,y,'rx') %mark the point
if button==1
xx=[xx x];yy=[yy y];
end
end
This will save the points the user selected into xx and yy vectors until the user presses another button than 1 (left mouse button on my system)
  5 Comments
Philip
Philip on 27 Feb 2011
Great! Thanks for your help!! :)

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