1. Softcopy Photogrammetry
Dr. Frank L. Scarpace
Civil and Environmental Engineering
Environmental Remote Sensing Center
University of Wisconsin-Madison
April 15, 2003
F.L.Scarpace

2. Outline Definition of Softcopy Photogrammetry
Why is this technology used ?
Determining Elevations using Softcopy Technology
Automatic Terrain Measurement
Demonstration of the technology
April 15, 2003
F.L.Scarpace

3. Softcopy Photogrammetry
Also known as Digital Photogrammetry
Mathematics is the same as in traditional Photogrammetric technology.
The images (diapositives) are replaced by scanned aerial images.
Measurements and image viewing are on a computer screen instead of through high quality optics.
April 15, 2003
F.L.Scarpace

4. Why Softcopy?
The principal reason this technology has been adapted is the potential for almost complete automation of the Aerial Triangulation process.
Aerial Triangulation is the least expensive method of determining the orientation of images within a block of aerial photos.
April 15, 2003
F.L.Scarpace

5. Softcopy Photogrammetry
Orientation
(ASPRS, 1980)
6 Parameters define the orientation for an aerial image at the time of exposure.
The location of the image:
Xc,Yc, and Zc
And the pointing direction:
, , and 
April 15, 2003
F.L.Scarpace

6. Measurement of Elevation
Once the Orientations for a stereo pair of digital images are known, the elevation for a point in the overlap area can be determined.
This is usually accomplished by viewing the images on the computer monitor in 3-D and clicking on the appropriate location.
April 15, 2003
F.L.Scarpace

7. Measurement of Elevation
April 15, 2003
F.L.Scarpace

8. Automatic Terrain Measurement
Almost all elevations within Softcopy systems used in production are determined manually by an experienced operator.
Potentially this process can be automated, saving both time and money.
The ATM technology uses area matching techniques to find corresponding points within a stereo pair.
April 15, 2003
F.L.Scarpace

9. Automatic Terrain Measurement
* Many more elevation points can be found using this technique compared to manual methods.
* The number of points are comparable to those measured with LIDAR.
* Currently, the Automatic Terrain Measurement technology generates too many errors to make it practical.
April 15, 2003
F.L.Scarpace

10. Automatic Terrain Measurement
Left Image Right Image
Reference Window
Search Window
Pull-In Region
Search Direction
Reference Image
Search Image
SEARCH EXAMPLE
April 15, 2003
F.L.Scarpace

11. Demonstration of ATM
April 15, 2003
F.L.Scarpace