pratica6_ex2.m

pkg load image

f = imread('Solda.bmp');
hf = imhist(f);
figure,imshow(f),figure,plot(hf);
S = 255;
T = 65;

J = regiongrow(f, S, T) 
%REGIONGROW Perform segmentation by region growing. 
%   [G, NR, SI, TI] = REGIONGROW(F, SR, T).  S can be an array (the 
%   same size as F) with a 1 at the coordinates of every seed point 
%   and 0s elsewhere.  S can also be a single seed value. Similarly, 
%   T can be an array (the same size as F) containing a threshold 
%   value for each pixel in F. T can also be a scalar, in which 
%   case it becomes a global threshold.    
% 
%   On the output, G is the result of region growing, with each 
%   region labeled by a different integer, NR is the number of 
%   regions, SI is the final seed image used by the algorithm, and TI 
%   is the image consisting of the pixels in F that satisfied the 
%   threshold test.  
 
%   Copyright 2002-2004 R. C. Gonzalez, R. E. Woods, & S. L. Eddins 
%   Digital Image Processing Using MATLAB, Prentice-Hall, 2004 
%   $Revision: 1.4 $  $Date: 2003/10/26 22:35:37 $ 
 
f = double(f); 
% If S is a scalar, obtain the seed image. 
if numel(S) == 1 
   SI = f == S; 
   S1 = S; 
else 
   % S is an array. Eliminate duplicate, connected seed locations  
   % to reduce the number of loop executions in the following  
   % sections of code. 
   SI = bwmorph(S, 'shrink', Inf);   
   J = find(SI); 
   S1 = f(J); % Array of seed values. 
end 
  
TI = false(size(f)); 
for K = 1:length(S1) 
   seedvalue = S1(K); 
   S = abs(f - seedvalue) <= T; 
   TI = TI | S; 
end 
 
% Use function imreconstruct with SI as the marker image to 
% obtain the regions corresponding to each seed in S. Function 
% bwlabel assigns a different integer to each connected region. 
[g, NR] = bwlabel(imreconstruct(SI, TI)); 

subplot(2,2,1);imshow(J)
subplot(2,2,2);imshow(g)
subplot(2,2,3);imshow(SI)
subplot(2,2,4);imshow(TI)