Photogrammetric Determination of Glacial Sediment Transfer
-    Kari Kajuutti, University of Turku
-    Henrik Haggrén, Helsinki University of Technology
 

Photogrammetric tasks

1. 3-D digitizing of the glazier surface geometry.
2. Texture mapping of the surface model.

Content

1. Phase 1: "Projective stereo", 1994-1995
2. Phase 2: "Rectified wide-angle image mosaicks", 1998-1999

Phase 1: "Projective stereo"

• Terrestrial stereo photography
• f = 500 mm, 135-size, b/w-negative
• base/distance ratio of 25 m : 1500 m (< 1 : 60)
• two stereo sequences: A and B
• 13 images for A(LEFT) and A(RIGHT)
• 14 images for B(LEFT) and B(RIGHT)
• f = 200 mm stereo photography for "ground control"
• Procedure
• relative orientation based on singular correlation
• projective rectification to the normal case of stereo photography
• DTM sampling using a digital stereometer: (X, Y, Z) = f(x', y', px)
• geometric modeling of the glazier surface as triangles
• texture mapping of the triangles by back projection
• Critical issues
• narrow angle photography
• lack of ground control
• Images

1. Nisqually Glacier on Mount Rainier.


2. Nisqually Glazier (Kari Kajuutti, 1995)


3. Terrestrial photography, block "13 images for A(LEFT)", f = 500 mm.


4. Terrestrial photography, block "14 images for B(LEFT)", f = 500 mm.


5. Projective relative orientation of two images.


6. Measurement on rectified stereo pair (Tuula Hannonen, 1995).


7. Terrestrial stereo photography for "ground control", block "A(LEFT)", f = 200 mm.


8. Textures on TIN surface model (Tuula Hannonen, 1995).

Phase 2: "Rectified wide-angle image mosaicks"

• Terrestrial stereo photography
1. as in "Phase 1"
• Aerial photography for "ground control"
1. f = 150 mm
2. h = 4200 m, b/h =  1 : 2,5
3. distances on ground for scaling
• Procedure
1. aerial triangulation for building a control network
2. primary DTM sampling using aerial photography
3. densification of DTM using terrestrial photography
• building of wide-angle image mosaicks by projective rectification
• 1 image for A(LEFT) and A(RIGHT)
• 1 image for B(LEFT) and B(RIGHT)
• orientation of both stereo pairs to the control network
4. texture mapping using original images
• Critical issues
1. unknown interior orientation of terrestrial photography
2. poor base/distance ratio of terrestrial photography
• Images

1. Aerial photogaphy (USGS, 1995).

 

2. Projective rectification of two cocentric images onto a common image plane.


3. Projective rectification of cocentric image mosaick


4. Rectification of two images (P. Pöntinen, 1998)