MATLAB: How can i remove the white object from binary image

Question

I have a image with my needed object (green) and the noise (white). I want to delete the noise but have no idea for that. anyone can help

Answer 1

You can use regionprops to compute circularity, eccentricity, or use major axis and minor axis lengths to find required shape of blob.

I used major and minor axis:

img = logical(rgb2gray(imread('green.png')));
dilate_img = imdilate(img,strel('disk',2));
BW = bwlabel(dilate_img);
blobprops = regionprops(BW, 'MajorAxisLength','MinorAxisLength', 'Eccentricity');
allMajorAxisLength = [blobprops.MajorAxisLength];
allMinorAxisLength = [blobprops.MinorAxisLength];
allEccentricity = [blobprops.Eccentricity];
MajorbyMinor = allMajorAxisLength./allMinorAxisLength;
[B,I] = sort(MajorbyMinor);
BW2 = ismember(BW,I(1));
% Using eccentricity
% [B,I] = sort(allEccentricity); % eccentricity = 0: circle, = 1: line
% BW2 = ismember(BW,I(1));
figure, 
subplot(131), imshow(img), title('Original');
subplot(132), imshow(BW), title('Label');
subplot(133), imshow(BW2), title('desired');