MATLAB Answers

Circle detection for eye

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Teik Jin Lim
Teik Jin Lim on 18 Nov 2019
Commented: Image Analyst on 19 Nov 2019
Hi everyone, I am stuck with this for weeks. After I input a face image,
First: I perform the viola jones eye region detection by using the vision.CascadeObjectDetector
Second: I perform the Canny edge detection based on the eye region that was detected during the first stage.
a = imread('face.jpg');
imshow(a);
detector = vision.CascadeObjectDetector('EyePairSmall');
bbox = step(detector,a);
out = insertObjectAnnotation (a,'rectangle',bbox,'detection');
subplot(2,2,1),subimage(out);
outb = imcrop(out,bbox);
[hog1,visualization] = extractHOGFeatures(outb,'CellSize',[8 8]);
subplot(2,2,2),subimage(outb);
I = rgb2gray(outb);
BW = edge(I,'canny');
subplot(2,2,3);
imshow(BW);
After that, the image shown is like this:
May I know how can I detect the iris (circle shape) based on the output of Canny edge detection ?
As the region has will only have two circles detected, how is it possible to be implemented ?
I read about the imfindcircle before, but it doesn't work out. Might need the community helps and some guidance on this.
Much appreciated. Thank you !

  2 Comments

KALYAN ACHARJYA
KALYAN ACHARJYA on 18 Nov 2019
Iris circle?
Teik Jin Lim
Teik Jin Lim on 19 Nov 2019
Yaya. Iris circle

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Answers (1)

Image Analyst
Image Analyst on 19 Nov 2019
Why are you using edge detection???
I'd first try thresholding the red channel, and if that is not robust enough, try imfindcircles().

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Image Analyst
Image Analyst on 19 Nov 2019
mask = rgbImage(:,:,1) < someThresholdValue; % You pick what someThresholdValue is.
Try adjusting some of the parameters to imfindcircles().
Teik Jin Lim
Teik Jin Lim on 19 Nov 2019
Can you write it in complete form ? I donno what are you talking about. Too random haha.
I am new to Matlab
Image Analyst
Image Analyst on 19 Nov 2019
OK, what is the name of your image? What did you call the variable?
Can you attach the cropped eye image alone? (Use imwrite()).

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