A binary contour follower
[x,y] = follow(Img)
[x,y] = follow(Img, 4)
[x,y] = follow(Img, 8)
follow extracts parametric contours of binary
objects. This is useful for further extracting object features such as
curvature and bending energy.
It is assumed that Img has only one object
y both store the parametrized
contour. In other words,
(x(i), y(i)) is a point of the
contour, where the coordinate system is assumed as starting from bottom-left
corner (0,0) to uper-right corner of the image. To get the (row,col) matrix
coordinates, use the transformation below:
row = size(Img,'r') - y col = x+1
The second argument is an optional parameter, being 4 or 8 depending if the border following is to be made in 4- or 8-neighborhood sequence, yielding a 4- or 8-connected contour.
follow(Img) equals follow(Img, 8).