MATLAB: Please I want to modify that code for run length to work on gray scale image

image analysisimage processingrun length

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I want to modify that code to make it work on grayscale image not binary image can anyone help me
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function out=rle(image)
%





% RLE(IMAGE) produces a vector containing the run-length encoding of
% IMAGE, which should be a binary image. The image is set out as a long
% row, and the conde contains the number of zeros, followed by the number
% of ones, alternating.
%
% Example:
%
% rle([1 1 1 0 0;0 0 1 1 1;1 1 0 0 0])
%
% ans =
%
% 03453
%
level = graythresh(image);
BW = im2bw(image, level);
L=prod(size(BW));
im=reshape(BW',1,L);
x=1;
out=[];
while L ~= 0,
temp=min(find(im == x));
if isempty(temp),
out=[out L];
break
end;
out=[out temp-1];
x=1-x;
im=im(temp:L);
L=L-temp+1;
end;
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Please I want to modify that code to make it work on grayscale image not binary image can anyone help me

Best Answer

There is no Run Length defined for matrices, but only for vectors. Even your code converts the input image to a vector at first in:
im=reshape(BW',1,L);
So simply call FEX: RunLength by:
img    = rand(640, 480);         % Example image data
imgV   = reshape(img.', 1, []);  % Convert to vector
[B, N] = RunLength(imgV);
If you do not have a compiler installed or speed doesn't matter, user the included RunLength_M. Or cut the needed lines only:
function [b, n] = rle(ImageMatrix)
x = reshape(ImageMatrix.', [], 1);
d = [true; diff(x) ~= 0];   % TRUE if values change
b = x(d);                   % Elements without repetitions
k = find([d', true]);       % Indices of changes
n = diff(k);                % Number of repetitions
end
By the way: Your code is not a Run Length Encoder. The example from the help section
rle([1 1 1 0 0;0 0 1 1 1;1 1 0 0 0])
does not reply 03453, but only 3. This means that the posted code does not work. In consequence I cannot replace it directly by a method working with gray scale images. The commands graythresh and im2bw seems, like the code should work with grey scale images already.
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