Superimpose a coloured Marker on a tiff image

I have a 12 bit Tif image and want to highlight on the image itself with a red circle all the pixels that have a value >4000. This was my attempt, but Im missing something?

[ii,jj]=find(IM>4000)  %Get x,y coordinates of all values >4000 and plot
hold on
plot(ii,jj,'Color','r','o')

Thanks Jason

Answer 1

[Image Analyst]

You got (the very badly named) ii and jj reversed. find() returns [rows, columns] which is [y, x]. You plotted ii,jj which is y,x, not x,y like you incorrectly assumed, so you're plotting the transpose. Don't worry, confusing row,column with x,y is a very very common mistake. Try this:

[rows, columns] = find(IM>4000);
plot(columns, rows, 'ro');

Or better yet, just create an image with red pixels instead of plotting circles in the overlay.

[Jason]

Fantastic, silly mistake! Thanks for your help.