Remote Sensing, Principles and Applications

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Remote Sensing, Principles and Applications

• HUMAN VISION

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Remote Sensing, Principles and Applications
HUMAN VISION

• All image data must pass through the eye to be
  interpreted
• Physically the eye has features in common with a
  camera

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Remote Sensing, Principles and Applications
HUMAN VISION

• Very wide field of view
• Stereoscopic vision
• Blind spot

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Remote Sensing, Principles and Applications
HUMAN VISION

• The eye carries out high level image processing -
  cameras do not.
• Artefacts can be created during interpretation
• Remember the canals of Mars

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Remote Sensing, Principles and Applications
HUMAN VISION

• COLOUR VISION
• Two types of light sensors
• Rods
• Cones

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Remote Sensing, Principles and Applications
HUMAN VISION

• COLOUR VISION
• RODS
• Only detect grey levels
• Operate at low light levels
• Evenly distributed in the eye
• Can detect 16 - 24 shades of grey

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Remote Sensing, Principles and Applications
HUMAN VISION

• COLOUR VISION
• CONES
• Three separate versions - blue, green, red
• Responsible for colour vision
• Operate at high light levels
• Concentrated in the eye center
• Can detect at least 8 million colours

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Remote Sensing, Principles and Applications
HUMAN VISION

• COLOUR BLINDNESS
• Most common - green, red
• Red and green cones are shifted too close
  together
• Can detect greyscale better

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Remote Sensing, Principles and Applications
HUMAN VISION

• COLOUR VIEWING
• Additive viewing
• Subtractive viewing

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Remote Sensing, Principles and Applications
HUMAN VISION

• ADDITIVE COLOUR
• Blue, green, red primaries
• Mimics the operation of the eye
• Used in photography and Computer display

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Remote Sensing, Principles and Applications
HUMAN VISION

• SUBTRACTIVE COLOUR
• Cyan, yellow, magenta primaries
• Used in printing and painting

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Remote Sensing, Principles and Applications
HUMAN VISION

• COLOUR CO-ORDINATE THEORY
• Hue, saturation and intensity
• Munsell colour charts