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Contour Tracing & Line Following

version 1.0 (3.98 KB) by

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



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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 :

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.

Comments and Ratings (8)

How can I use this algorithm as line follower? I don't know how I must edit it to get a line follower robot.



how can i merge between Image Acquisition Toolbox and line tracing ???

kikac4 Chawla

i downloaded your function, contour_trace from the matlab central website. i am attempting to run it and am getting the following error message:

??? Attempted to access BW(49,745); index out of bounds because size(BW)=[165,744].

do you have any ideas on how to fix this error? BW is a binary image

Tony Yin

Doesn't work :(

another contour_trace User

It doesn't work in most of cases.

Yuan Luo

it may work in tracing a one-pixel binary curvature, but not work in finding contour of large closed area

Stijn Helsen

With a test, it didn't work well. The contour points were found, but not in the right order (many quick jumps between two parts of the contour appeared).

contour_trace User

Very helpful for tracing the entire contour if one of the point on the contur is know. Can be used in contour segmentation - if one point on the contour is known/detected

MATLAB Release
MATLAB 6.5 (R13)

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