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Alessandro Mannini

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Computer Engineering - University of Florence - Italy

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24 Nov 2010 Screenshot Freeman Chain Code Gives Freeman chain code 8-connected representation of a boundary Author: Alessandro Mannini chain code, freeman, boundary, contour, representation, chaincode 95 21
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23 Apr 2014 Freeman Chain Code Gives Freeman chain code 8-connected representation of a boundary Author: Alessandro Mannini

Hi Monalisa, see the description and previous comments. Main steps are:
1) get the contour of the image
2) put coords of contour points in b
3) call chaincode(b,true/false)

Note: the contour must be 8-connected tha is, given a point on the boundary it must have only two neighbors, the previous and the next. There can be NO forks.

09 May 2012 Freeman Chain Code Gives Freeman chain code 8-connected representation of a boundary Author: Alessandro Mannini

Hi Ann, look to my previous comments (ex. 19/3/2011) the b parameter is an array containing coords of boundary points that should be 8-connected. 8-connected means that if Bn is the n-th element of b and Bn+1 the next their x y coords should satisfy this relations: | Xn - Xn+1 |<=1 AND | Yn - Yn+1 |<=1. Start checking that with a simple example. Regards Alessandro

17 Apr 2012 Freeman Chain Code Gives Freeman chain code 8-connected representation of a boundary Author: Alessandro Mannini

Hi Frb, please note than b contains coords of boundary points order so that they are 8-connected. The find function you use return coords of boundary points but in a different order. From Matlab Help seems it scans matrix column by column. Best regards Alessandro

19 Mar 2011 Freeman Chain Code Gives Freeman chain code 8-connected representation of a boundary Author: Alessandro Mannini

Look at description inside source code:

% b - boundary as np-by-2 array;
% np is the number of pixels and each element is a pair (y,x) of
% pixel coordinates

For example, if you have 4 points p=(y,x) like this p1=(5,1);p2=(5,2);p3=(4,2);p4=(3,1) b is:

b = [ 5 1;5 2;4 2;3 1]

note that points must be 8-connected.

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25 May 2014 Freeman Chain Code Gives Freeman chain code 8-connected representation of a boundary Author: Alessandro Mannini cspit

Maximum recursion limit of 500 reached. Use set(0,'RecursionLimit',N)
to change the limit. Be aware that exceeding your available stack space can
crash MATLAB and/or your computer.

Error in ==> imformats>find_in_registry

what should i do now??

28 Apr 2014 Freeman Chain Code Gives Freeman chain code 8-connected representation of a boundary Author: Alessandro Mannini Das, Monalisa

Hi, I keep getting the error "the xpression to the left of the equals sign is not a valid target" when I try to use the [cc]= chaincode(b,u)...what am I doing wrong?

23 Apr 2014 Freeman Chain Code Gives Freeman chain code 8-connected representation of a boundary Author: Alessandro Mannini Mannini, Alessandro

Hi Monalisa, see the description and previous comments. Main steps are:
1) get the contour of the image
2) put coords of contour points in b
3) call chaincode(b,true/false)

Note: the contour must be 8-connected tha is, given a point on the boundary it must have only two neighbors, the previous and the next. There can be NO forks.

23 Apr 2014 Freeman Chain Code Gives Freeman chain code 8-connected representation of a boundary Author: Alessandro Mannini sujith

if u don't want to unwrap,just change function name to [cc] = chaincode(b)
and remove the unwrapping section from program.trace the boundary of your image using 'bwtraceboundary' function and input it to chain code function.

21 Apr 2014 Freeman Chain Code Gives Freeman chain code 8-connected representation of a boundary Author: Alessandro Mannini Das, Monalisa

Hi, could you tell me how to use this function to get chaincode for an image? Thanks!

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