Contour Tracing & Line Following

Contour tracing in a binary image given a point on the contour.

Contour Tracing of a Black White Image (Binary Image).

Save this file in the MATLAB/Work folder and on the MATLAB Command Prompt type "help contour_trace"
Assuming Foreground to be in Black and Background to be in White, this function traces the entire contour and requires row and column value of any pixel which lies on the contour and returns the (row,column) values of all the points which lie on the contour.

This can be used in Line Following Algorithms also.

Syntax :
[pixel,I]=contour_trace(BW,r,c)

Input :
r,c - row, column value of a single pixel on the contour.
BW - Black & White Image (Binary Image).

Output :
I - Binary Image containing just the desired contour.
pixel - N x 2 matrix which stores the pixel value of the contour, column1 gives the rows & column2 the corresponding column.