Air Photos

Air Photos
- Stereo Viewing
  - vision
    - reflected light from object -> eye -> nerve -> brain
    - monocular vs. binocular
    - stereoscopy
      - use of binocular vision
      - overlapping pair of air photos
      - form a 3D image in our brain (gives depth & distance)
      - conditions
        
        stereo pair
        
        properly aligned
        
        stereoscope (separates view for each eye)
  - stereoscopes
    - lens
      - cheap
      - portable (brief case)
      - 2x's magnification
    - mirror
      - no overlap
      - entire stereo area viewable
      - room to work
      - no lens distortion
  - Proper Set-Up
    - select stereo pair (or a triplet)
    - locate fiducial marks
    - locate PP on each photo (hey! what's a "PP"?)
    - locate CPP on each photo (visual assessment)
    - (orient shadows towards you)
    - align photos with straight edge - recreates flight line
    - adjust photo distance - match dist. to stereoscope (inter-pupil dist.)
    - align stereoscope with flight line
    - fine tune photo distance
  - orthophoto