Colour Perception

Colour Perception

https://en.wikipedia.org/wiki/Color_vision

Physiology

• Light sensitivity
  • Seeing Purple (source: https://www.quora.com/Why-does-purple-light-appear-blue-in-cameras/answer/Bill-Otto-5))
  • Human Eye Quantum Efficiency (see how cones percieve some blue light as red):
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  • Normal Quantum Efficiency:
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    • Canon D450 Quantum Efficiency:
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• Rod and Cone Cells
  • Cone Cells
    • Are three types - Short (S), Medium (M), Long (L)
    • Gives colour vision
    • Most are sensitive to 555 nm (Green)
  • Rod Cells
    • Gives low-light vision at 500 nm

Mathematics

• Physical color is a combination of pure spectral colours (in the visible range)
• Hilbert Space \(H_{colour}\) (Infinite Dimensional Vector Space) holds all colours
• Euclidian Spaces
• Each element \(C\) of \(H_{colour}\) is a function that gives an interval of all the colours \([W_{min}, W_{max}]\) to real numbers \(w\)
• So human percievable colours can be modelled by 3 numbers, to the extend to which each cone cell - S,M,L is stimulated by a wavelength \(w\) as \(s(w)\), \(m(w)\) and \(l(w)\).
• This can be thought of as points in a 3-dimensional Euclidian Space, and we call this the \({R^3}_{colour}\)