Matlab Region Growing Error Message - matlab

Question

I am experiencing an error in Matlab.
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.
The algorithm I am using is the one downloaded from:
http://www.mathworks.com/matlabcentral/fileexchange/19084-region-growing
Here is the code:
function J=regiongrowing(I,x,y,reg_maxdist)
% This function performs "region growing" in an image from a specified
% seedpoint (x,y)
%
% J = regiongrowing(I,x,y,t)
%
% I : input image
% J : logical output image of region
% x,y : the position of the seedpoint (if not given uses function getpts)
% t : maximum intensity distance (defaults to 0.2)
%
% The region is iteratively grown by comparing all unallocated neighbouring pixels to the region.
% The difference between a pixel's intensity value and the region's mean,
% is used as a measure of similarity. The pixel with the smallest difference
% measured this way is allocated to the respective region.
% This process stops when the intensity difference between region mean and
% new pixel become larger than a certain threshold (t)
%
%
% Author: D. Kroon, University of Twente
I = im2double(imread('ship.jpg'));
x=150; y=150;
J = regiongrowing(I,x,y,0.2);
figure, imshow(I+J);
if(exist('reg_maxdist','var')==0), reg_maxdist=0.2; end
if(exist('y','var')==0), figure, imshow(I,[]); [y,x]=getpts; y=round(y(1)); x=round(x(1)); end
J = zeros(size(I)); % Output
Isizes = size(I); % Dimensions of input image
reg_mean = I(x,y); % The mean of the segmented region
reg_size = 1; % Number of pixels in region
% Free memory to store neighbours of the (segmented) region
neg_free = 10000; neg_pos=0;
neg_list = zeros(neg_free,3);
pixdist=0; % Distance of the region newest pixel to the regio mean
% Neighbour locations (footprint)
neigb=[-1 0; 1 0; 0 -1;0 1];
% Start regiongrowing until distance between region and possible new pixels become
% higher than a certain threshold
while(pixdist<reg_maxdist&&reg_size<numel(I))
% Add new neighbours pixels
for j=1:4,
% Calculate the neighbour coordinate
xn = x +neigb(j,1); yn = y +neigb(j,2);
% Check if neighbour is inside or outside the image
ins=(xn>=1)&&(yn>=1)&&(xn<=Isizes(1))&&(yn<=Isizes(2));
% Add neighbour if inside and not already part of the segmented area
if(ins&&(J(xn,yn)==0))
neg_pos = neg_pos+1;
neg_list(neg_pos,:) = [xn yn I(xn,yn)]; J(xn,yn)=1;
end
end
% Add a new block of free memory
if(neg_pos+10>neg_free), neg_free=neg_free+10000; neg_list((neg_pos+1):neg_free,:)=0; end
% Add pixel with intensity nearest to the mean of the region, to the region
dist = abs(neg_list(1:neg_pos,3)-reg_mean);
[pixdist, index] = min(dist);
J(x,y)=2; reg_size=reg_size+1;
% Calculate the new mean of the region
reg_mean= (reg_mean*reg_size + neg_list(index,3))/(reg_size+1);
% Save the x and y coordinates of the pixel (for the neighbour add proccess)
x = neg_list(index,1); y = neg_list(index,2);
% Remove the pixel from the neighbour (check) list
neg_list(index,:)=neg_list(neg_pos,:); neg_pos=neg_pos-1;
end
% Return the segmented area as logical matrix
J=J>1;
I have attempted to change the value as suggested by set(0,'RecursionLimit',N) but this just crashes Matlab if it goes over 1000.

Answer 1

The error message makes sense since you've added the following lines to the function
I = im2double(imread('ship.jpg'));
x=150; y=150;
J = regiongrowing(I,x,y,0.2);
figure, imshow(I+J);
and so it will call itself (recurse) repeatedly. These four lines need to be removed from regiongrowing and should only be used from the Command Line (or another script/function).