I have to detect my elbow. I'm able to produce an image in which I'm facing the camera, standing before it and my arms are in my body plane(body plane is plane containing my head,chest,and legs)(i.e. to say that my arms don't stick out of this plane though they may be placed on my chest parallel to the body plane). Then using skin detection I'm getting my both arm, hand and palm.(I'm wearing half shirt so little portion of my arm is detected between elbow and shoulder). Then using convex hull defect method the point giving the largest defect should be my elbow.

This thing is fine theoretically but does not work practically. Before using the convex hull and defects method my hand and arm contour is a bit wavy (and if the waves become a bit more high then that point is detected as my elbow than the real one). Or if i use polynomial approximation method then also it is not detecting.

Skeletonization of image takes considerable time and I'm doing this real time.(My image has two contours of my both hands, that's it).

I'm doing this in opencv c++. Any Help is appreciated.

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    $\begingroup$ Could you provide (an) example image(s)? Also, the image(s) of the intermediate steps would help. $\endgroup$ – penelope Jun 5 '12 at 12:13
  • $\begingroup$ I wouldn't use skin color, is not really robust. If your problem is very specyfic and just for it's ok. I would try to do background subtraction, then arm (the whole arm) segmentation, and the elbow should be the middle point. Skeletonization should work also realtime, if you do it just for the arms. $\endgroup$ – Jav_Rock Jun 5 '12 at 15:27
  • $\begingroup$ in background subtraction your body will also come so if your hand is on top of your chest it won't be detected,Hence I decided to use skin colour $\endgroup$ – Roney Island Jun 5 '12 at 16:11
  • $\begingroup$ is there some function like matlab's spline to detect v shaped objects and mebbe from therein i may locate elbow? $\endgroup$ – Roney Island Jun 6 '12 at 2:55
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    $\begingroup$ For detecting bodyparts you have several approaches. Some of them use appearance models, others shape templates, skin color, etc. You should read papers on the topic firstto get state-of-the-art ideas. $\endgroup$ – Jav_Rock Jun 6 '12 at 13:12

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