How to detect white regions in image

Question

Pat 2014-11-11

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/162286-how-to-detect-white-regions-in-image

评论： Pat 2014-12-7

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

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Image Analyst 2014-11-11

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/162286-how-to-detect-white-regions-in-image#answer_158559

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.

2 个评论
显示无隐藏无

Pat 2014-11-12

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 2014-11-12

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.

请先登录，再进行评论。