Title: Remote Sensing, Principles and Applications
1Remote Sensing, Principles and Applications
2Remote 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
3Remote Sensing, Principles and Applications
HUMAN VISION
- Very wide field of view
- Stereoscopic vision
- Blind spot
4Remote 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
5Remote Sensing, Principles and Applications
HUMAN VISION
- COLOUR VISION
- Two types of light sensors
- Rods
- Cones
6Remote 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
7Remote 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
8Remote 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
9Remote Sensing, Principles and Applications
HUMAN VISION
- COLOUR VIEWING
- Additive viewing
- Subtractive viewing
10Remote Sensing, Principles and Applications
HUMAN VISION
- ADDITIVE COLOUR
- Blue, green, red primaries
- Mimics the operation of the eye
- Used in photography and Computer display
11Remote Sensing, Principles and Applications
HUMAN VISION
- SUBTRACTIVE COLOUR
- Cyan, yellow, magenta primaries
- Used in printing and painting
12Remote Sensing, Principles and Applications
HUMAN VISION
- COLOUR CO-ORDINATE THEORY
- Hue, saturation and intensity
- Munsell colour charts