Gamma Correction
You have an intensity value I with a range [0,1] and there is a perceived intensity p

Ideal case - 0.5 is half has bright as 1.0 (THIS IS NOT THE REALITY THOUGH)
Therefore we have to use the gamma function p = I^gamma

Gamma Correction
Given a pixel intensity I, the displayed intensity after gamma correction is equivalent to
I_d = I^(1/gamma)

There will be 3 different coordinates systems that will be encountered during this class.

Image Coordinate System
In an image coordinate system, the origin is at the top left corner.
We use the following formula
I_r(x,y) = data[3*(x + width*y)] for RED
I_g(x,y) = data[3*(x + width*y) + 1] for GREEN
I_b(x,y) = data[3*(x + width*y) + 2] for BLUE

OpenGL Texture Coordinate System
OpenGL textures place the origin (0,0) in the lower left corner, so to convert from the Image Coordinate System, we must use the following function
I_{LL}(x,y) = I(x_{LL}, image_height - y_{LL})



OpenGL/Viewport/Window Coordinate System
Has the origin in the center and has a bounding box [-1,1] in both dimensions.
The function to transform points from the Image Coordinate System to the OpenGL/Viewport coordinate system is

x_new = 2.0 * (x_image + 0.5) / width  - 1.0
y_new = - [ 2.0 * (y_image + 0.5) / height - 1.0 ] 


Image Compositing & Blending - the process of overlaying one image onto another (used a lot in green screen movies)
r=[0,1]
g=[0,1]
b=[0,1]
alpha=[0,1]

alpha is the transparency value where
alpha=0 -> fully transparent
alpha=1 -> fully opaque

alpha values are useful for blending images and compositing