We’ve all experienced taking photographs in which everyone ends up with bright red devil eyes. So the question arises "Why ....? " Why Do Eyes Look Red in Photos? In dim light or at night, pupil very often expands due to lack of light. As camera's flash goes on, pupil doesn't have time to react (contract). Therefore, a large burst of light reaches the retina, reflects back on camera There’s a layer on the back of the eye called the choroid which is full of blood causing the reflection color to be red. Many cameras now have a setting, it shoots a series of flashes before the camera takes a picture allowing time for the pupil to construct accordingly. But the good thing is we can remove it using ImageProcessing Techniques discussed below. How to remove Red-Eyes Automatically? Step1: Eye detection We will use the standard OpenCV Haar detector (haarcascade_eye.xml) for eyes detection . To keep things simple, assume the image is a face portra
(a)Final Blended Image (b) Background Image (c)Foreground Image Alpha blending Alpha blending is the process of overlaying a foreground image with transparency over a background Image. The transparent image is generally a PNG image.It consists of four channels (RGBA).The fourth channel is the alpha channel which holds the transparency magnitude. Image (b) is a background image and image (c) is the foreground / overlay image. Image (a) is the final blended image obtained by blending the overalay image using the alpha mask. Below is the image(Fig d) of the alpha channel of the overlay image. (d).Alpha Channel At every pixel of the image, we blend the background and foreground image color(F) and background color (B) using the alpha mask . At every pixel value of alpha lie in range(0,255), a pixel intensity of 0 means black color and pixel instensity of 255 means whit