# how can I remove all the objects that are not connected to my central object in a binary image?

9 views (last 30 days)
jack nn on 8 Jun 2015
Commented: sajid rahim on 6 Jul 2017
I have a binary Image that includes some objects. the shape of these objects are irregular. the object that is in central of this image is important for me . how can I remove all the objects that are not connect to my central object? for example if this is my image:
I want to have this as output:
I have a lot of images that are like these example and I should separate central object.so I should find a general way for this.

#### 1 Comment

sajid rahim on 6 Jul 2017
hi i see ur comments can you plz send me the code plzzzzz

Image Analyst on 8 Jun 2015
Just find the centroids with regionprops() and then find the distances from each blob to the center of the image. Then use min to find the index of the blob closest to the middle. Here is some untested code just off the top of my head.
% Give each blob a unique ID number (a label).
labeledImage = bwlabel(binaryImage);
% Get centroids.
measurements = regionprops(labeledImage, 'Centroid');
centroids = [measurements.Centroid];
xCentroids = centroids(1:2:end);
yCentroids = centroids(2:2:end);
% Find distances to middle of image
distances = sqrt((columns/2-xCentroids).^2 + (rows/2-yCentroids).^2);
% Find the min distance
[minDistance, indexOfMin] = min(distances);
% Extract binary image of only the closest blob
centralBlob = labeledImage == indexOfMin;
imshow(centralBlob);

Show 1 older comment
jack nn on 9 Jun 2015
thanks, Image Analyst and Ashish Uthama.I used this code and I got the result that I wanted.I should test this for other images.I really appreciated your help.
Image Analyst on 9 Jun 2015
You're welcome. If it works, then can you click the "Accept this Answer" link? Thanks in advance.
sajid rahim on 6 Jul 2017
Hi jack nn i try the codes but not work proprely I think I may make some mistake... sooo plz send me the code plzzzzzzzzzz