exist an method for find extreme points in imagemagick?

[diegomage]

like this



Please help me

[fmw42]

If you threshold your hand image and make it white on black showing the hand properly thresholded, then you do -morphology edgein and get the hand outline. Then convert that to txt and filter using grep "white". You will get all edge pixels that way.

[diegomage]

yes i see better draw a rectangle for contain the image and use compare for compare points

[snibgo]

I think diegomage wants the top-most point of the hand, and the left-most and right-most and bottom-most points.

If so, then make a white hand on a black background. "-trim" finds the bounding rectangle. The first white pixel in that image is the top-most point of the hand. Crop to the first column, and any white pixel in that crop if the left-most point of the hand.

[fmw42]

But that does not find the cyan dot in at the lower left of the hand. I think he would need the convex hull corner points. So perhaps see http://www.imagemagick.org/Usage/morpho ... convexhull

[diegomage]

i see an example in this post

http://stackoverflow.com/questions/3156 ... -in-opencv


The answer is in imagemagick the title may confuse

[fmw42]

That link pertains more to your other question.

[fmw42]

You can get the convex hull from the link I provided after thresholding. Then you could try my script corners to find the line vertices of the convex hull. Alternately, use -canny to get the edges and -hough-lines to get straight lines for the edges of the convex hull, then from the straight lines you could find the intersections of the lines. See

viewtopic.php?f=4&t=25405
viewtopic.php?f=4&t=25476

[diegomage]

very thanks

[snibgo]

I don't know exactly what is wanted. Perhaps the cyan dot is (one of) the bottom-most pixels in the hand.

True, it could be the most south-west point. But the most south-east point isn't wanted?

[diegomage]

the instersection points between the convex hull and the countour of this hand

[diegomage]

the red points of this image for example

[snibgo]

These are two different problems.

the instersection points between the convex hull and the countour of this hand

This would be about 20 pixels. Okay, then get the convex hull (see http://www.imagemagick.org/Usage/morphology/ ) and the edge, and find the intersection.

the red points of this image for example

This would be seven pixels. Perhaps these are the vertices of the convex hull.