How to do segmentation for detecting microaneurysms?

hi, please help me. i want to create a program for the detection of microaneuryms in diabetic retinopathy diseases. i have retinal image and success doing vascular segmentation. the point is, i've been using a region growing from http://www.mathworks.com/matlabcentral/fileexchange/32532-region-growing-2d3d-grayscale but it just give me one object of microaneurysm like this

i want the result like this

this is my original image after using adaptive histogram

what should i do? or is there a recommended method that i can use?

Answer 1

[Nitin]

Hope this gets you started:

I=imread('retinal.PNG'); I2 = rgb2gray(I); I_bin = I2>150;

In the next step, you can choose the smaller regions you are interested in using bwselect and or regionsprops based on your criteria

Answer 2

[Image Analyst]

People have done this before and published their methods. Look for them in section 20.5 here:

http://www.visionbib.com/bibliography/contentsmedical.html#Medical%20Applications,%20CAT,%20MRI,%20Ultrasound,%20Heart%20Models,%20Brain%20Models

Most likely, you'll find robust algorithms won't be just a hundred or two hundred lines long, as I don't expect that it's a simple problem.

A quick and dirty, non-robust method would be something like this

1. threshold image
2. find areas and perimeters
3. remove largest region (the main vessel network)
4. compare circularities (Perimeter^2/(4*pi*area)) of remaining regions and keep regions with low circularity values to keep compact blobs rather than stick-like blobs.

[Mustapha Seidu]

Hi, this is the second time I am coming across this link today. Can you provided an updated link pls? This particular one has nothing relating to the problem. Thank you.

[Image Analyst]

Where was the first one, if you still remember. Obviously the link worked once but I guess they changed it from

http://iris.usc.edu/Vision-Notes/bibliography/contentsmedical.html#Medical%20Applications,%20CAT,%20MRI,%20Ultrasound,%20Heart%20Models,%20Brain%20Models

to the new link:

http://www.visionbib.com/bibliography/contentsmedical.html#Medical%20Applications,%20CAT,%20MRI,%20Ultrasound,%20Heart%20Models,%20Brain%20Models

I'll change it in my original answer also.