Background Flashcards
(49 cards)
What is a (non-digital) image? (1)
f(x,y) = colour/intensity
What is sampling?
TODO
What is quantisation?
TODO
What is required for vision? (3)
- Light source
- Eyes
- Object that reflects/transmits light
Draw diagrams to represent the 3 types of viewing mechanisms (3)
TODO 19
What determines the spectrum of wavelengths arriving at the eye? (2)
- Spectrum of wavelengths emitted by light
2. Spectrum of wavelengths reflected/transmitted by object
What is light? (1)
Electromagnetic radiation
What is the range of wavelengths of visible light? (2)
700nm -> 400nm
What colour is light of wavelength 700nm? (1)
Red
What colour is light of wavelength 400nm? (1)
Violet
What wavelength is red light? (1)
700nm
What wavelength is blue/violet light? (1)
400nm
Why does the colour characteristic of light emitted vary for different illuminants? (3)
- Light is composed of multiple electromagnetic wavelengths
- Different wavelengths are emitted with different intensities
- The composition of these determines the colour characteristics
What is an illuminant? (1)
TODO
Why are incandescent light bulbs very red? (1)
Wavelengths in the red region are emitted with the HIGHEST INTENSITY
Draw a diagram of the human eye indicating the retina, fovea and optic nerve. (1)
TODO 26
What is the retina? (1)
An array of light detection cells
What is the fovea? (2)
- High resolution area of the retina
2. Highest density of cone cells
What does the optic nerve do? (1)
It takes signals from the retina to the visual cortex of the brain
How many light receptors are in the retina? (1)
150 million
How many nerve fibres are in the optic nerve? (1)
1 million
Why does the retina need to perform pre-processing?
There are 150M light receptors in the retina but only 1M nerve fibres in the optic nerve -> the amount of information received by the retina needs to be condensed to fit onto the optic nerve
Name 3 ways the retina performs pre-processing. (3)
- Avg. multiple inputs
- Colour signal processing
- Local edge detection
How is colour signal processing performed in the retina? (1)
TODO