How to find all regions of the same color?

Question

arman Yaraee 2011-10-21

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评论： Stephen23 2015-11-30

Hi guys. I wrote a piece of code which finds all the points with the same color as I selected:

In this part we just find the coordinates of the required co

im = imread('Lighthouse.jpg');
n = 1;
figure, imshow(im)
[x,y] = ginput(n);
x = floor(x);
y = floor(y);
%colour(length(x),3);
colour = zeros(1,length(x),3, 'uint8');
for i=1:length(x)
    for  k=1:3
           colour(1,i,k) = im(y(i),x(i),k);
      end
  end
  %image(colour);
  %axis off;

Now that I have the colour, I want to search the picture for all the points with the same colour.

[r,c,t] = size(im);
counter = 1;
for i=1:r
    for j=1:c
              if (im(i,j,:) == colour(1,1,:))
                  coordr(counter) = i;
                  coordc(counter) = j;
                   counter = counter+1;
              end
      end
  end

This way I found all the points with the color the user selected! Now my problem is:

it takes long time to process!!
I want to select colors which are close to my color but I dunno the algorithm to do it! (this is my main problem) because the points which are found are not enough!

for example they are about 200 points in a big picture. they will be seen as dots! any ideas?

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Answer 1

Walter Roberson 2011-10-21

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John D'Errico has a MATLAB File Exchange contribution for Fuzzy Color Matching

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Answer 2

Image Analyst 2011-10-21

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arman: I suggest you abandon that approach and use my delta E based approach in my File Exchange: http://www.mathworks.com/matlabcentral/fileexchange/?term=authorid%3A31862 That uses an industry standard method (delta E) for determining color difference. I believe it will do exactly what you want.

Walter, fuzzy color was one of the submissions that John removed and never replaced. As I recall it didn't do color segmentation anyway but was some sort of a name assignment scheme, though. I still have his code though. He says "Fuzzycolor is a tool for identifying the "color name" of any RGB intensity triad, i.e., sets of 3 color values....."

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Answer 3

lya lya 2015-11-28

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Dear Image Analyst,

Do you still have the Fuzzy Color code from John? If so, I hope you can share it with me.

Thanks.

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lya lya 2015-11-28

Thanks!

Stephen23 2015-11-30

You can also try my FEX submission, which identifies colornames based on RGB values but uses the "industry standard method (delta E) for determining color difference":

http://www.mathworks.com/matlabcentral/fileexchange/48155-convert-between-rgb-and-colornames

It also supports many standard sets of named colors, such as CSS, dvips, HTML, Kelly, MacBeth, MATLAB, Wolfram, X11, xcolor, xkcd,...

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