MATLAB Image processing filtering

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Rusty
Rusty on 15 Jan 2016
Edited: Rusty on 17 Jan 2016
One sample image is http://goo.gl/0IOkBZy .Download the file and name it as
My code is
Now here , I am getting two regions, one the small area (1) and the other as the big one (2)

Accepted Answer

Walter Roberson
Walter Roberson on 15 Jan 2016
bwareafilt() if you have a newer MATLAB. If not then regionprops() 'Area' and select only the smaller of the two regions.
  3 Comments
Walter Roberson
Walter Roberson on 15 Jan 2016
Edited: Walter Roberson on 15 Jan 2016
Look at the eccentricity of the region. The split regions are probably not going to be as circular as the region you want.
Also, image dilation would have a good chance of joining back together the split large region long before the dilation reached the region of interest.
Rusty
Rusty on 15 Jan 2016
Actually I am new to image processing. I also tried image dilation and image erosion but I failed. Could you please help me more?

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More Answers (2)

Image Analyst
Image Analyst on 15 Jan 2016
For that particular image, you can use
labeledImage = bwlabel(binaryImage);
smallBlob = ismember(labeledImage, 2) > 0;
In general somehow you have to identify the blob you want, then use ismember() to extract it. For this one, I know that you have only 2 blobs and that the small inside one will be blob #2 because of the way it does labeling. But in general (like your second image), you may have to use regionprops() to get other measurements to identify the particular blob(s) you want, and then use ismember(). See my Image Segmentation Tutorial http://www.mathworks.com/matlabcentral/fileexchange/?term=authorid%3A31862 for examples of that where I pick out different coins in the image.
You may also want to learn about bwareafilt() or bwselect().
  7 Comments
Image Analyst
Image Analyst on 16 Jan 2016
But you never posted any image where they were connected. Anyway, if you do have images like that, you can split them apart with code Steve put on his blog: http://blogs.mathworks.com/steve/2013/11/19/watershed-transform-question-from-tech-support/ Please try Steve's code on your image and if you can't tweak it enough to get it working, then post that image and your script back here.
Rusty
Rusty on 16 Jan 2016
Sir, I have posted the new image ( in which I am facing problem). Please have a look at it. Thanks

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harjeet singh
harjeet singh on 16 Jan 2016
try to use this code for these type of image, but not for every slice
clear all
close all
clc
img=imread('ok2.jpg');
img=rgb2gray(img);
img1=img>mean(img(:));
img2=imfill(img1,'holes');
se=strel('disk',2);
img2=imdilate(img2,se);
img3=img2 & ~img1;
img4=imfill(img3,'holes');
img5=img4 & ~img3;
img6=bwareaopen(img5,100);
figure(7)
imshow(img6)
  3 Comments
Rusty
Rusty on 16 Jan 2016
Actually I did something else. YOu can see a video of my simulation: at https://goo.gl/kWd88X. I use the methods told by imageAnalyst in his tutorials. Could you please help me solving this algorithm using watershed?

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