www.pudn.com > ms_segmenter.rar > Gray_segment.m

function [New_image, Sorted_modes] = ... 
   Gray_segm (Gray_image, Window_radius, Min_group_size) 
% Gray_segment - segment a gray-level image according to Meer's algorithm 
% reads image from the file, finds significant maxima by mean shift algo  
% (to generalize to the case of 3-d vectors), groups all the pixels  
% whose color falls within the given interval (with peak being the  
% center, and Window_radius being the radius),  
 
% Min_group_size : need at least that many pixels to qualify for a color 
 
Rows = size(Gray_image, 1); 
Cols = size(Gray_image, 2); 
Min_image_size = 0.005*Rows*Cols;		% to stop when image is small 
Gray_image = round(Gray_image); 
 
% creating a new array - color based 
Cumulative = sparse(1, max(max(Gray_image))+1); 
for i=1:Rows 
   for j=1:Cols 
      Cumulative(Gray_image(i, j)+1) = Cumulative(Gray_image(i, j)+1)+1; 
   end 
end 
 
Cumulative(1) = 0;		% corresponds to only manually zeroed out regions 
k = 0; L = length(Cumulative); 
while sum(Cumulative) > Min_image_size 
   Non_zero_pos = find(Cumulative > 0); 
   if length(Non_zero_pos) == 0 
      break; 
   end 
    
   Initial = Non_zero_pos(1); 
   [Mode, Number_values] = M_shift1(Cumulative, Window_radius, Initial); 
   Mode = full(round(Mode)); 
    
   if Number_values > Min_group_size% good group 
		k = k+1; 
      Modes(k) = Mode; 
      Cumulative(max(1, Mode-Window_radius):min(L, Mode+Window_radius)) = ... 
      zeros(size(Cumulative(max(1, Mode-Window_radius): ... 
      min(L, Mode+Window_radius)))); 
   else 
      Cumulative(max(1,Initial-Window_radius):min(L,Initial+Window_radius)) =... 
      zeros(size(Cumulative(max(1, Initial-Window_radius): ... 
      min(L, Initial+Window_radius)))); 
   end 
end 
 
Sorted_modes = sort(Modes); 
New_image = zeros(size(Gray_image)); 
for i=1:k 
	To_group = find((Gray_image >= Sorted_modes(i)-Window_radius)... 
		& (Gray_image < Sorted_modes(i)+Window_radius)); 
	New_image(To_group) = i; 
end 
% Gray_image == 0 added to provide for background detection 
To_zero = find(Gray_image == 0); 
New_image(To_zero) = 0;