Color, Image Filtering Flashcards
What do rods and cones do in our eyes
Rods detect light, cones detect color
Where are cones more concentrated in our eyes
Closer to the centre of our peripheral vision
Human vision is based on 3 colors, what is the term for this
Trichromatic vision
Why is RGB not the most efficient way of storing images?
Each channel, R G and B has lots of information, the image can be recognized by looking at any channel, meaning there should be a more efficient way of storing the image channels.
What are the channels in Y Cb Cr image encoding
Y = Luminance
Cb = Blue Difference (from luminance)
Cr = Red Difference (from luminance)
What are the channels in YUV image encoding
Y = Luminance
U, V = Chroma
What is the alpha channel for in image encoding
The alpha channel represents the opacity/transparency of the image
Cross correlation vs. convolution
Cross correlation - The filter/kernel is slid across all elements, performing element wise multiplication at each step, then summing
Convolution - the kernel is flipped horizontally and vertically before sliding across elements, then performing element wise multiplication and summing
Properties of convolution
Associative - ab = ba
Commutative - a(bc) = (ab)c
Distributes over addition - a(b+c) = ab + ac
Scalars factor out - kab = akb = k(ab)
Noise
Visual artifacts that occur because the camera cannot fully approximate the image
What’s a way we can sharpen an image with a gaussian filter
Take the gaussian filter of the image = imgaus
Sharpened image = image + (image-imgaus)
What type of noise is median filter good at removing
Salt and pepper noise
