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Photogrammetry. Quantitative Measurements from Aerial Photography Flightlines of Vertical Aerial Photography Stereoscopic Vision and Stereoscopes Photo Alignment for 3D Visualization Orthophotographs and DEMs Reminder: Read Chapter 7 (pp. 193-218) for next class.

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Photogrammetry
Photogrammetry

  • Quantitative Measurements from Aerial Photography

  • Flightlines of Vertical Aerial Photography

  • Stereoscopic Vision and Stereoscopes

  • Photo Alignment for 3D Visualization

  • Orthophotographs and DEMs

  • Reminder: Read Chapter 7 (pp. 193-218) for next class


http://www.dailymotion.com/video/xc4ixx_weatherman-freaking-out-over-dc-sno_shortfilmshttp://www.dailymotion.com/video/xc4ixx_weatherman-freaking-out-over-dc-sno_shortfilms


What quantitative measurements can be obtained from a single vertical aerial photograph
What Quantitative http://www.dailymotion.com/video/xc4ixx_weatherman-freaking-out-over-dc-sno_shortfilmsMeasurements can be obtained from a Single Vertical Aerial Photograph?

  • Scale

  • Object length

  • Area of photography or feature

  • Perimeter of feature


What quantitative measurements can be obtained using overlapping stereoscopic aerial photographs
What Quantitative http://www.dailymotion.com/video/xc4ixx_weatherman-freaking-out-over-dc-sno_shortfilmsMeasurements can be obtained using Overlapping Stereoscopic Aerial Photographs

  • Precise planimetric locations

  • Precise object height

  • Planimetrically accurate orthophotographs

  • Digital Elevation Models (DEMs)

  • Slope and aspect derived from DEMs


Flightline of Vertical Aerial Photography http://www.dailymotion.com/video/xc4ixx_weatherman-freaking-out-over-dc-sno_shortfilms

Jensen, 2000


Block of Vertical Aerial Photography http://www.dailymotion.com/video/xc4ixx_weatherman-freaking-out-over-dc-sno_shortfilms

Jensen, 2000


Block of Vertical Aerial Photography Compiled into an Uncontrolled Photomosaic

Columbia, SC

Original scale = 1:6,000

Focal length = 6” (152.82 mm)

March 30, 1993

Jensen, 2000


Flightline #4 Uncontrolled Photomosaic

Photo #5

Columbia, SC

Original scale = 1:6,000

Focal length = 6” (152.82 mm)

March 30, 1993

Jensen, 2000


Geometry of Overlapping Vertical Aerial Photographs Uncontrolled Photomosaic

• Principal Points

• Conjugate PrinciplePoints

Jensen, 2000


Geometry of A Vertical Aerial Photograph Obtained Over Uncontrolled Photomosaic

Flat Terrain



Enlargement of A Portion of Terrain

Flightline #4, Photo #5

Jensen, 2000


Geometry of A Vertical Aerial Photograph Collected Over Variable Relief Terrain

Jensen, 2000


Measurement of Object Height From A Single Aerial Photograph Based on Relief Displacement

Line of flight

Jensen, 2000


Measurement of Object Height From A Single Aerial Photograph Based on Shadow Length on Level Terrain

Sun’s rays

Jensen, 2000


Stereoscopic vision
Stereoscopic Vision Based on Shadow Length on Level Terrain

What is stereoscopic vision and what is its significance for remote sensing?


Stereoscopic vision1
Stereoscopic Vision Based on Shadow Length on Level Terrain

  • 3-D effect occurs when an object is viewed from two different, but overlapping, viewpoints

  • Human eyes – up to ~1,000 m

  • Aerial photography – two successive aerial photos with at least 60% forward overlap will provide stereoscopic aerial photography

  • Basis for 3-D effect


Parallactic Angles Used During Depth Perception Based on Shadow Length on Level Terrain

0.119”

59.1’

Jensen, 2000


Stereoscopic Viewing Methods Based on Shadow Length on Level Terrain

Jensen, 2000


Stereoscopes
Stereoscopes Based on Shadow Length on Level Terrain

  • Deflect our normally converging lines of sight so each eye views a different image

  • Lens (pocket) stereoscope

  • Reflecting stereoscope

  • Zoom stereoscope

  • Stereoplotters


Photo alignment
Photo Alignment Based on Shadow Length on Level Terrain

  • Identify principal point of each photograph

  • Locate conjugate principal point (or point(s) that corresponds to principal point on adjacent photos)

  • Align points with flight line (straight line)


Geometry of Overlapping Vertical Aerial Photographs Based on Shadow Length on Level Terrain

• Principal Points

• Conjugate PrinciplePoints

Jensen, 2000


Lens Stereoscope with Parallax Bar Based on Shadow Length on Level Terrain

Jensen, 2000


Stereoscopic Parallax Principles Based on Shadow Length on Level Terrain

Jensen, 2000


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