How to detect white regions in image

I have a code below to detect exudates from retina Images

clc;
close all;
clear all;
workspace; % Display workspace panel.
% filename = 'C:\Documents and Settings\tk2013\My Documents\Temporary
% stuff\fundus.jpg';
rgbImage = imread('2.jpg');
[rows columns numberOfColorPlanes] = size(rgbImage);
subplot(3, 3, 1);
imshow(rgbImage, []);
title('Original color Image');
set(gcf, 'Position', get(0,'Screensize')); % Maximize figure.
tic;
redPlane = rgbImage(:, :, 1);
greenPlane = rgbImage(:, :, 2);
figure,imshow(redPlane)
 K = imadjust(redPlane);
 figure
 imshow(K)
  SE = strel('rectangle',[7 5]);
BW3 = imdilate(K,SE);
 figure,imshow(BW3)
s=strel('square',12);
h=(imclose(BW3,s));
 figure,imshow(h)

      greenPlane=h;
   [pixelCountsG GLs] = imhist(greenPlane);
  % Ignore 0
  pixelCountsG(1) = 0;
  % Find where histogram falls to 10% of the peak, on the bright side.
  tIndex = find(pixelCountsG >= .1*max(pixelCountsG), 1, 'last');
  thresholdValue = GLs(tIndex)

binaryGreen = greenPlane>thresholdValue;
binaryImage = imfill(binaryGreen, 'holes');
% Get rid of blobs less than 5000 pixels.
binaryImage = bwareaopen(binaryImage, 5000);
figure,imshow(binaryGreen)

but the final output is only black,kindly help to extract the exudates from the above code,I have attached the images,I tried with different thresholds but could not get answer

Answer 1

[Image Analyst]

So much wrong but I don't have time to fix it all. For starters, comment out the bwareaopen() function. And plot the histogram so you can see its shape.

[Pat]

Sir in the link u have given the code for green channel for fundus image http://www.mathworks.in/matlabcentral/newsreader/view_thread/273785

I tried it for red channel but could not process ,can u tell what must be changed in your code for processing red channel

[Image Analyst]

The red plane will have the least contrast. The blue or green channel will have more. That's why in my code I chose the green channel. But then you inserted code to adjust and do morphology on the red channel and then stick that modified red channel image into a variable deceptively named greenChannel.

I'm not going to have time to look at this for several days, if at all, so I ask you to look at algorithms published here http://www.visionbib.com/bibliography/contentsmedical.html#Medical%20Applications,%20CAT,%20MRI,%20Ultrasound,%20Heart%20Models,%20Brain%20Models in Section 20.5, where people show how they've successfully done it. There is no need to invent your own algorithm when people have been working for months or years on algorithms and have published them for you to simply implement.

Answer 2

[Siam]

Your question is not clear. According to your code you need to concentrate (threshold and bwareaopen). You will get exactly what you are looking for.

[Pat]

Absolutely and onother thing is that can that optic nerve be removed,can u attach the code plz

[Pat]

Thanks can you tell how to remove optic nerve plz

[Pat]

i is oh for colour,but how to process for red channel

[Siam]

your question is how to detect white regions. Now you want to remove nerves. Nerves have different color and therefore; it will not show in binary image but will show black according to the code. Not sure what do you mean by remove optic nerves.

[Pat]

sorrry siam i meant optic disc that circular portion

[Siam]

Is it something like this?

What exactly you are trying to do while removing the nerves? You need to explain a little more. Do you want complete white region?

[Pat]

yes exactly the same as in binary image

[Pat]

kindly update the code

[Pat]

hello Siam i need the same output as u have given above,kindly can you give the code plz

[Pat]

helo siam can u guide me in getting the output,i tried hreshlding,but could not get answer

[Siam]

Are you still having issues to get the result?

[Pat]

no siam got results