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Photogrammetry Quantitative Measurements from Aerial Photography Quantitative Measurements from Aerial Photography Flightlines of Vertical Aerial Photography.

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Presentation on theme: "Photogrammetry Quantitative Measurements from Aerial Photography Quantitative Measurements from Aerial Photography Flightlines of Vertical Aerial Photography."— Presentation transcript:

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

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6 What Quantitative Measurements can be obtained from a Single Vertical Aerial Photograph? Scale Scale Object length Object length Area of photography or feature Area of photography or feature Perimeter of feature Perimeter of feature

7 What Quantitative Measurements can be obtained using Overlapping Stereoscopic Aerial Photographs Precise planimetric locations Precise planimetric locations Precise object height Precise object height Planimetrically accurate orthophotographs Planimetrically accurate orthophotographs Digital Elevation Models (DEMs) Digital Elevation Models (DEMs) Slope and aspect derived from DEMs Slope and aspect derived from DEMs

8 Flightline of Vertical Aerial Photography Jensen, 2000

9 Block of Vertical Aerial Photography Jensen, 2000

10 Block of Vertical Aerial Photography Compiled into an Uncontrolled Photomosaic Jensen, 2000 Columbia, SC Original scale = 1:6,000 Focal length = 6” ( mm) March 30, 1993 Columbia, SC Original scale = 1:6,000 Focal length = 6” ( mm) March 30, 1993

11 Flightline #4 Photo #5 Flightline #4 Photo #5 Jensen, 2000 Columbia, SC Original scale = 1:6,000 Focal length = 6” ( mm) March 30, 1993 Columbia, SC Original scale = 1:6,000 Focal length = 6” ( mm) March 30, 1993

12 Geometry of Overlapping Vertical Aerial Photographs Principal Points Principal Points Conjugate Principle Points Conjugate Principle Points Geometry of Overlapping Vertical Aerial Photographs Principal Points Principal Points Conjugate Principle Points Conjugate Principle Points Jensen, 2000

13 Geometry of A Vertical Aerial Photograph Obtained Over Flat Terrain Geometry of A Vertical Aerial Photograph Obtained Over Flat Terrain

14 Geometry of A Vertical Aerial Photograph Collected Over Flat Terrain Jensen, 2000

15 Enlargement of A Portion of Flightline #4, Photo #5 Enlargement of A Portion of Flightline #4, Photo #5 Jensen, 2000

16 Geometry of A Vertical Aerial Photograph Collected Over Variable Relief Terrain Jensen, 2000

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18 Measurement of Object Height From A Single Aerial Photograph Based on Relief Displacement Jensen, 2000 Line of flight

19 Measurement of Object Height From A Single Aerial Photograph Based on Shadow Length on Level Terrain Jensen, 2000 Sun’s rays

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

21 Stereoscopic Vision 3-D effect occurs when an object is viewed from two different, but overlapping, viewpoints 3-D effect occurs when an object is viewed from two different, but overlapping, viewpoints Human eyes – up to ~1,000 m Human eyes – up to ~1,000 m Aerial photography – two successive aerial photos with at least 60% forward overlap will provide stereoscopic aerial photography Aerial photography – two successive aerial photos with at least 60% forward overlap will provide stereoscopic aerial photography Basis for 3-D effect Basis for 3-D effect

22 Parallactic Angles Used During Depth Perception Jensen, ” 0.119” 59.1’ 59.1’

23 Stereoscopic Viewing Methods Jensen, 2000

24 Stereoscopes Deflect our normally converging lines of sight so each eye views a different image Deflect our normally converging lines of sight so each eye views a different image Lens (pocket) stereoscope Lens (pocket) stereoscope Reflecting stereoscope Reflecting stereoscope Zoom stereoscope Zoom stereoscope Stereoplotters Stereoplotters

25 Photo Alignment  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)

26 Geometry of Overlapping Vertical Aerial Photographs Principal Points Principal Points Conjugate Principle Points Conjugate Principle Points Geometry of Overlapping Vertical Aerial Photographs Principal Points Principal Points Conjugate Principle Points Conjugate Principle Points Jensen, 2000

27 Lens Stereoscope with Parallax Bar Jensen, 2000

28 Stereoscopic Parallax Principles Jensen, 2000


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