MATLAB: How to find distance between two points in an image

distanceimage analysisimage processingImage Processing Toolbox

hello! i have an image something like this.

how to obtain the distance between the dot above i and the line in i? the image of i is attached below.

please help me with the code… thank you!

Best Answer

try to use this

img=imread('i2.png');
figure(1)
imshow(img)
hold on
[lab,num]=bwlabel(img);
[r,c]=find(lab==1);
[r1,c1]=find(lab==2);
D = pdist2([r c],[r1 c1],'euclidean'); % euclidean distance
[r2,c2]=find(D==min(D(:)));
point_1=[r(r2) c(r2)];
point_2=[r1(c2) c1(c2)];
plot([point_1(2) point_2(2)],[point_1(1) point_2(1)],'r')
hold off
distance=sqrt( (point_1(1)-point_2(1)).^2 + (point_1(2)-point_2(2)).^2)

distance =

   42.1070

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MATLAB: How to find minimum distance between two cylindrical objects from binary image

By using bwperim, regionprops and pdist2 functions, you can obtain the minimum distance and corresponding points on each object, like:

% Import your image and binarize
I = imread('aa.jpg');
BW = imbinarize(rgb2gray(I));
% Measure the minimum distance
BW2 = bwperim(BW,8);
stats = struct2table(regionprops(BW2,'PixelList'));
dist = pdist2(stats.PixelList{1},stats.PixelList{2});
[dmin,idx] = min(dist(:));
[r,c] = ind2sub(size(dist),idx);
pt1 = stats.PixelList{1}(r,:);
pt2 = stats.PixelList{2}(c,:);
% Show the result
imshow(BW)
hold on
plot([pt1(1) pt2(1)],[pt1(2) pt2(2)],'r-o','LineWidth',2)
disp(sprintf('Min. distance: %f [pixel]',dmin))

The minimum distance in pixel was measured to be:

Min. distance: 476.822818 [pixel]

MATLAB: How do you find the centroid of a particular Blob

Since you're working with a binary image here, BW2, you can use the bwpropfilt function to clean up the small areas.

BW2 = bwpropfilt(BW2, 'Area', 1);

The last input argument determines the largest # of regions to keep, so it can be lowered to just the one. From there regionprops would only detect the single centroid.

You could also pass area as an input to regionprops as it is and use the centroid of the largest area.

measurements = regionprops(BW2, 'Centroid', 'Area');
[~,ind] = max(cat(1,measurements.Area));
centroid = measurements(ind).Centroid;

Best Answer

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MATLAB: How to find minimum distance between two cylindrical objects from binary image

MATLAB: How do you find the centroid of a particular Blob

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