find spots in image

and I use the code, then I can find the spots.
----------
clear all;
Cimg=imread('CropTest1.jpg','jpg');
Gimg=rgb2gray(Cimg);
BW=Gimg>150;
rp=regionprops(BW,Gimg,'WeightedCentroid');
disp('Centroiding is done.');
figure(1); image(Cimg); axis image; hold on;
n=numel(rp);
for i=1:n
plot(rp(i).WeightedCentroid(1), rp(i).WeightedCentroid(2), 'r*')
end
----------
and I have coordinates of all spots.
then I want to do these
- express Center spot -> (0,0)
- find missing spots (-1,3),(5,1),(1,-5) and output the message: '(-1,3),(5,1),(1,-5) are missing!'
- delete one spot in double spots that use this idea: distance of two spots(well, I seem to be able to do this.)
thank you for your advice and help.

 采纳的回答

I can't see your images, though I'm in Beijing this week and imageshack.us seems to be another domain in a long list of web sites I've encountered that are banned by the government of China. Nonetheless, I'll try to help as best I can without seeing your images. I'm assuming that you have a 10 by 10 array of possible locations of the circles. You first define a logical array initialized to false that says whether or not you have a circle there. Then set it to true when you find a circle there. Try something like this (untested)
circlePresent = false(10,10);
% Then loop over circles you have found setting the array to true.
centroids = [rp.WeightedCentroid];
[rows, columns] = size(BW);
for k = 1 : length(rp)
if centroids(k, 2) < rows/10
row = 1;
elseif centroid(k, 2) < 2*rows/10
row = 2;
elseif centroid(k, 2) < 3*rows/10
row = 3;
% and so on up to 10.
% Then do the same for columns.
if centroids(k, 1) < columns/10
column = 1;
% etc.
% Now set the array to true for this circle
circlePresent(row, column) = true;
end
% Now find missing elements
[missingRows, missingColumns] = find(~circlePresent);
% Print out all the missing circles array locations.
for k = 1 : length(missingRows)
fprintf('There is a circle missing at row %d, column %d.\n', ...
missingRows(k), missingColumns(k));
end

5 个评论

Wow... How do you know without looking images? After some modify your answer, I complete the work. Thanks a lot. :D
Image Analyst
Image Analyst 2013-7-27
编辑:Image Analyst 2013-7-27
I guess because I'm that good. :-)
I'm leaving for Japan tomorrow so I'll be able to access sites again.
Thank you for your continuous attention. :D
If you reply later, I compare your answer with mine.
i did not get anything. matlab only tells that CONTINUE ENTERING STATEMENT what should do
I have no idea what you're referring to. Start your own thread, post your own code and image, and I'll see what I can do.

请先登录,再进行评论。

更多回答(1 个)

Elad
Elad 2013-7-27

0 个投票

I would try imfindcircles(), (or hough transform to find circles if you don't have the toolbox). You can adjust the sensitivity and edge until you find all the spots. Than you can calculate the average intesity in each circle and have full control on your results.
Here is an example in the image processing blog, using imfindcircles: http://imageprocessingblog.com/detecting-and-counting-objects-with-circular-features/

4 个评论

Thank you for your help.
I tried imfindcircles function. Despite I adjust sensitivity and edge, but there is still one missing point at (1,-5). Even if I find all points, how can I get WeightedCentroid? :'(
You might be able to get the missing point by changing the ObjectPolarity to 'dark', and to approximate the "Weighted Centroid" by the circles centers.
But Nevermind, I see it worked out for you anyway. :)
Elad
Elad 2013-7-27
编辑:Elad 2013-7-27
[centers, radii] = imfindcircles(clb1,[8 15],'Sensitivity',0.91,'Edge',0.01);
gets all the spots but one.
[centers, radii] = imfindcircles(clb1,[8 15],'Sensitivity',0.9,'Edge',0.01,'ObjectPolarity','dark');
gets the last spot.
Wow! actually, I feel the limit of regionprops when bright backgrounds. I will try this way.
Thank you for your help. :D

请先登录,再进行评论。

类别

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by