How to create a linkage between different blob?

Question

Tan Wen Kun 2015-12-1

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/258336-how-to-create-a-linkage-between-different-blob

编辑： Tan Wen Kun 2015-12-3

采纳的回答： Walter Roberson

matrix.jpg

在 MATLAB Online 中打开

For example I using watershed and get different color piece.

I want to create a matrix to show the linkage.

1 1 1 1 1 1 1 1 1 1
2 2 1 3 3 1 4 4 0 1
2 1 3 3 1 0 4 4 0 1
1 1 1 1 1 1 1 1 1 1

so when loop vertical and horizontal I wish to get the result like matrix.jpg

I want check before 1 and after 1,

if check got 2,3 so return 1 to matrix(3,2)=1 matrix(2,3)=1

if check got 3,4 so return 1 to matrix(3,4)=1 matrix(4,3)=1

if 0 then ignore.

How to do this?

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Tan Wen Kun 2015-12-2

编辑：Tan Wen Kun 2015-12-2

blob.jpg

now I get the relationship table so I decide to merge them together based on the original image color pixel.

example blob.jpg:

blob 1(rgb=122,122,122) and blob 2(rgb=121,121,121) the color is nearly same(threshold maybe set to rgb+-10) so I reassign label blob 2 to label blob 1.

blob 3 maybe pixel value(10,12,13) on original image is huge different with blob 1 so I decide not merge to blob 1.

Problem I faced now is how to compare matrix of color blob (x,y)position with matrix impixel of original image so I can decide whether want to merge different blob together or not?

Walter Roberson 2015-12-2

You need to define when two colors are "nearly the same" or not. It is not an easy question, especially when you are working with the darker colors. For example, is [10,0,0] "nearly the same" as [0,0,0] because the values are within 10, or is [10,0,0] definitely "red" whereas [0,0,0] is "black" ?

You should look for some of what Image Analyst has posted about "Delta E"

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Answer 1

Walter Roberson 2015-12-2

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https://ww2.mathworks.cn/matlabcentral/answers/258336-how-to-create-a-linkage-between-different-blob#answer_201897

Use glcm on the blob numbers. This will give you counts instead of just yes/no, but you can get the yes/no by just testing whether the count > 0.

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Image Analyst 2015-12-2

Tan's question has nothing whatsoever to do with what he asking. It has nothing at all to do with delta E or merging blobs of the same color or adjacent blobs. He just asked a question without supplying context of prior questions. It's the old case of "Tell me how to do X" and then you say how to do X and then the poster says that it didn't work, and you say "Why not" and they say "Well because I want to do Y", after which you say, "well if you want to do Y, you definitely don't want to do X, you need to do Z".

Basically he wants to separate the two elephants in this labeled image:

So he started with the faulty premise that watershed would do the best job - and that's where all the trouble started. Watershed is notorious for over-segmenting regions, and then you have to do special tricks to repair that. Then he wants to "decide to merge them together based on the original image color pixel." But it appears from his comments that the colors he calls original are the pseudocolor label colors, not the original RGB image, so this is destined to fail. If anything he should look at the original RGB mean colors in each labeled region, not the arbitrary labeled image colors.

Or better yet, just use something like this:

http://www.mathworks.com/matlabcentral/fileexchange/37197-dem--diffused-expectation-maximisation-for-image-segmentation

Walter Roberson 2015-12-3

在 MATLAB Online 中打开

If you have a function that can return whether two rgb colors are "close" or not, then you pass in to that table the pseudocolor map indexed at the blob number. For example,

[ind_image, cmap] = rgb2ind(TheColorImage);
labeled_image = ind_image + 1;   %because first color of ind is 0
first_lab = labeled_image(7,38);   %label of one place in the image
second_lab = labeled_image(11,20);  %label of a different place in the image
first_color = cmap(first_lab,:);   %rgb corresponding
second_color = cmap(second_lab,:);  %rgb corresponding
if YourFunctionToTellIfColorsAreClose(first_color, second_color)
   ....
end

Tan Wen Kun 2015-12-3

编辑：Tan Wen Kun 2015-12-3

在 MATLAB Online 中打开

Because I got the blob table so I just need to compare like blob 1 is connected to blob 2 and 3 so I only compare the original rgb of blob 1 and 2 and then blob 3 and blob1.

This 2 line is label a position only~I need compare the median whole blob 1 in original image and median whole blob2 in original image.

first_lab = labeled_image(7,38);   %label of one place in the image
second_lab = labeled_image(11,20);  %label of a different place in the image

can I chg this to a loop so i can loop all the blob

for(x=1,x++,x<=maxblob)
first_lab=blob x
second_lab=blob x+1
first_color = cmap(first_lab,:);   %rgb corresponding
second_color = cmap(second_lab,:);  %rgb corresponding
end
if YourFunctionToTellIfColorsAreClose(first_color, second_color)
   //compare median rgb of blob x&&blobx+1 =threshold+-5
   //if first_color<= second_color threshold+-5 || first_color>=                
       second_color threshold+-5
   //chg label blob x+1 =blob x
end