In my work for hand motion recognition, I have clashed with problems for object`s contour recognition in the image. After some search and after some reading I have found some papers, which can be usefull for you too.
The first paper is describing Edge detecyion algorithm of Canny, known as JFC. You can find it here .
Also there is Source code of this algorithm written in C#. You can find it in codeproject.
The Second paper is BLOB analyses for had and hand detection. You can find it here .