added part of Canny documentation
added part of Canny documentation

hmeine/vigra,cbecker/vigra,hmeine/vigra,martinsch/vigra,stuarteberg/vigra,martinsch/vigra,capturePointer/vigra,funkey/vigra,hmeine/vigra,stuarteberg/vigra,kod3r/vigra,mmuellner/vigra,martinsch/vigra,DaveRichmond-/vigra,stuarteberg/vigra,cbecker/vigra,xiwei-zhang/vigra,cbecker/vigra,psteinb/vigra,hmeine/vigra,dagophil/vigra,cha007/vigra,mmuellner/vigra,kod3r/vigra,xiwei-zhang/vigra,stuarteberg/vigra,cha007/vigra,cbecker/vigra,DaveRichmond-/vigra,dagophil/vigra,mmuellner/vigra,psteinb/vigra,cha007/vigra,DaveRichmond-/vigra,dstoe/vigra,funkey/vigra,mmuellner/vigra,xiwei-zhang/vigra,dstoe/vigra,capturePointer/vigra,funkey/vigra,cha007/vigra,timoMa/vigra,mmuellner/vigra,xiwei-zhang/vigra,cbecker/vigra,hmeine/vigra,ThomasWalter/vigra,capturePointer/vigra,stuarteberg/vigra,kod3r/vigra,funkey/vigra,xiwei-zhang/vigra,psteinb/vigra,mmuellner/vigra,DaveRichmond-/vigra,dagophil/vigra,timoMa/vigra,dstoe/vigra,hmeine/vigra,dagophil/vigra,timoMa/vigra,timoMa/vigra,DaveRichmond-/vigra,xiwei-zhang/vigra,stuarteberg/vigra,capturePointer/vigra,ThomasWalter/vigra,timoMa/vigra,funkey/vigra,kod3r/vigra,funkey/vigra,kod3r/vigra,stuarteberg/vigra,capturePointer/vigra,xiwei-zhang/vigra,funkey/vigra,psteinb/vigra,DaveRichmond-/vigra,dagophil/vigra,dstoe/vigra,cbecker/vigra,martinsch/vigra,DaveRichmond-/vigra,ThomasWalter/vigra,dagophil/vigra,capturePointer/vigra,psteinb/vigra,mmuellner/vigra,psteinb/vigra,timoMa/vigra,martinsch/vigra,ThomasWalter/vigra,psteinb/vigra,kod3r/vigra,cha007/vigra,ThomasWalter/vigra,dstoe/vigra,hmeine/vigra,kod3r/vigra,martinsch/vigra,cha007/vigra,ThomasWalter/vigra,cha007/vigra,dstoe/vigra,timoMa/vigra,dstoe/vigra,dagophil/vigra,ThomasWalter/vigra,capturePointer/vigra