Face recognition and image normalization

How can I normalize image to align the eyes with a horizontal line.

EyeDetect = vision.CascadeObjectDetector('EyePairBig');
I = imread('1.jpg');
BB=step(EyeDetect,I);

As I understand I can rotate image by imrotate , but I need to know angle of the rotation.

Answer 1

[Dima Lisin]

If (x1,y1) is the center of the first eye, and (x2, y2) is the center of the second eye, then (y2 - y1) / (x2 - x1) is the tangent of the angle between the line connecting the two centers and the horizontal. You can get the angle using atan2(y2-y1, x2-x1).

[chinnurocks]

How to get centre points of the eyes... automatically... I mean without using the data cursor manually ?

[Image Analyst]

Segment out the eyes, then use regionprops().

Answer 2

[Image Analyst]

Be sure to see the Mathworks Webinar on Face detection/recognition on Nov. 13, 2014: Click Here