Find white region of eye

Question

I have used eye-cascade classifier and found the eyes and also I found the eye center using eye tracker as shown in the below image.

Now I am trying to find the white part of the eye as shown below.

Can someone help me out by providing some links are code snippets to find the white region of eye?

Answer 1

I am not sure but you could try to use the following strategy. I have used a similar kind of strategy before to find out something else.

1. Find out the center of the eyes.
2. blur your image and apply canny edge detector.
3. Find out the contours in your images obtained through step 2 (Edge image).
4. Check the % of white color in each and every contour by calculating a simple histogram.
5. Keep only those contours where the % of white color is quite high.
6. then check the distance between the center of eyes and the center of each white contour (because there could be some other white contours also in your image e.g. White cloth, paper etc.)
7. if the distance between the center of eyes and the center of white contour is less than some threshold value, keep it and discard rest of the contours.
8. Draw an outerline across the remaining contours (which should be 2, one for each eye).

I am not sure if the above mentioned technique would work in your case but you can give it a try as it is not too hard.

PS: The things which i have mentioned about blurring, Canny, Countour ...you can have a look at the somehow similar SO Post.