computer_vision

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course notes of Introduction of computer vision

image formation

  • four factors for production of image
    • composition
    • illumination
    • image formation
    • dithering
      : a process to increase the number of grey levels and colours that can be produced via a digital device
      eg. for 2x2 array of pixels, by dithering get 5 gray level instead of 2

optic
: study of behaviour of light

human visual system

  • components

    • eye

      • Cornea

      • Lens

        • flexible
      • Iris:
        • adjust the size of the pupil
      • pupil
        • adjustable opening
      • Retina
        • structure
          • central part: Fovea
            • ~2 degree
          • others: Periphrey
          • a small area: blind spot
            no visual sensation
        • Photoreceptors
          • rods and cones
            |rods|cones|
            |—|—|
            |low luminacs vision <1cd m2|high="" luminiance="" vision="">100cd/m2|
            |scotopic(green) vision|photopic(red))vision|
            |~120 million per retina|~7 million per ritina|
            |one type, peak spectral response at 510nm|three type, peak spectral res at S/red, M/blue, L/blue nm|
            |primarily located outside the forvea|primarily located inside the forvea|
            • ganglion cell
              • receptive field:
                1. spatial contrast
                2. color contrast
    • optical nerve
    • LGN: Lateral geniculate nucleus
    • V1 primary visual contax