how to select the object with the largest area ?

hi...i have i used bwconvhull to detect a certain part of the image, as you can see in the image that there are number of objects with certain centroids. what i want to do is to detect the object with the largest area(1st big one from the left) and neglect the others.

which method should i follow?

i will will be very thankful for your help.

following is the code(its very roughly written as i am still working on it. Sorry for any inconvenience in advance)

CH_objects = bwconvhull(c,'objects');
imshow(CH_objects);
title('Objects Convex Hull');
bwarea(CH_objects)

Ilabel =bwlabel(CH_objects,8);

stat = regionprops(Ilabel,'centroid');
imshow(CH_objects); hold on;
for x = 1: numel(stat)
    plot(stat(x).Centroid(1),stat(x).Centroid(2),'ro');
end

Answer 1

[Image Analyst]

I have a demo for exactly that purpose. Please click the blue link (ExtractBiggestBlob.m) below copy the program to MATLAB and run it.

[Image Analyst]

The main function is at the bottom:

% Function to return the specified number of largest or smallest blobs in a binary image.
% If numberToExtract > 0 it returns the numberToExtract largest blobs.
% If numberToExtract < 0 it returns the numberToExtract smallest blobs.
% Example: return a binary image with only the largest blob:
%   binaryImage = ExtractNLargestBlobs(binaryImage, 1)
% Example: return a binary image with the 3 smallest blobs:
%   binaryImage = ExtractNLargestBlobs(binaryImage, -3)
function binaryImage = ExtractNLargestBlobs(binaryImage, numberToExtract)

all the stuff above it to make a nice demo for you.

[hasan]

thank you sir. it helped me a lot.