How can I accurately plot the centroid of black dots in MATLAB?

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PamunkeBoy
PamunkeBoy 2018-6-6
评论： PamunkeBoy 2018-6-18
I have an Image in which I am trying to determine the centroid of the black dots. My Code seems to have trouble recognizing the centroid for all black dots as their respective shade of grey differs. Would anyone be able to guide me into how I could diagnose this? Thank you!
%%Centroid
clear,clc
grid on
X = imread('redbox_5.bmp');
figure
imagesc(X)
se = strel('disk',3);
J = imsubtract(imadd(X,imtophat(X,se)),imbothat(X,se));
figure
imshow(J)
newmap2 = contrast(J,2);
colormap(newmap2)
figure(2);imshow(J);
%grey point less than 30
BW=J<30;
%Find Weighted Centroid of the chosen dots and plot them together with original image
%https://www.mathworks.com/matlabcentral/answers/332938-how-to-identify-black-dots-using-matlab
rp=regionprops(BW,J,'WeightedCentroid');
n=numel(rp);
for j=1:n
Position(j,1)=rp(j).WeightedCentroid(1);
Position(j,2)=rp(j).WeightedCentroid(2);
end
for i=1:n-1
if (Position(i+1,1)-Position(i,1))<5 || (Position(i+1,2)-Position(i,2))<5
Position(i+1,1)=1/2*(Position(i,1)+Position(i+1,1));
Position(i+1,2)=1/2*(Position(i,2)+Position(i+1,2));
Position(i,1)=0;Position(i,2)=0;
end
end
[m,n]=size(Position);
figure(3);imshow(J); axis image; hold on;
for i=1:m
for j=1:n-1
plot(Position(i,j),Position(i,j+1),'r*')
end
end
Position(all(Position==0,2),:)=[];
display(Position);

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采纳的回答

Anton Semechko
Anton Semechko 2018-6-7
% Get the image
im=imread('https://www.mathworks.com/matlabcentral/answers/uploaded_files/120388/MATLAB_QUESTION.PNG');
im=max(im,[],3);
% Segment blobs
bw=imclose(im<60,strel('disk',5));
% Cenroids of individual blobs
RP=regionprops(bw,'Centroid');
N=numel(RP);
C=zeros(N,2);
for i=1:N, C(i,:)=RP(i).Centroid; end
% Centroid of all blobs
C_net=regionprops(double(bw),'Centroid');
C_net=C_net.Centroid;
figure
imshow(bw)
hold on
plot(C(:,1),C(:,2),'or','MarkerSize',10,'LineWidth',2)
plot(C_net(:,1),C_net(:,2),'*g','MarkerSize',10,'LineWidth',2)
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Image Analyst
Image Analyst 2018-6-16
It
(1) removes blobs that are not in the range (2 numbers) you specify, or
(2) removes or keeps the N largest or smallest blobs if you pass in a single number.
PamunkeBoy
PamunkeBoy 2018-6-18
Okay. I was also having trouble coding with imclose(). How am I supposed to code this?

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