WHAT CAN PHOTOS TELL US?
PHOTOGRAMMETRY IS A WAY TO DETERMINE THE SIZE AND SHAPE OF AN OBJECT FROM PHOTOGRAPHS OF IT RATHER THAN FROM THE ORIGINAL. BUT WHILE A PHOTOGRAPH GIVES THE ILLUSION OF DEPTH, IT IS STILL ONLY A TWO-DIMENSIONAL REPRESENTATION. IF, HOWEVER, THE CAMERA HAS A CONSTANT GEOMETRICAL RELATION BETWEEN THE IMAGE PLANE AND THE LENS, IT CAN SERVE AS A KIND OF THEODOLITE. MEASURING THE COORDINATES OF A POINT ON THE PHOTO THEN ALLOWS ONE TO FIND THE DIRECTION TO IT BY WORKING BACK THROUGH THE CAMERA GEOMETRY. BY TAKING TWO SUCH PHOTOS WITH THE CAMERA, BUT FROM DIFFERENT POSITIONS A KNOWN DISTANCE APART, THE SPATIAL LOCATION OF THE POINT CAN BE FOUND BY THE INTERSECTION OF THE TWO LINES OF SIGHT. THE SUBJECT IS RECONSTITUTED THREE-DIMENSIONALLY BY THUS ESTABLISHING A SERIES OF POINTS - USUALLY BY MEANS OF HIGHLY PRECISE, STEREOSCOPIC MEASURING AND PLOTTING INSTRUMENTS. /AUTHOR/
-
Supplemental Notes:
- No 69, pp 56-66, 6 FIG, 7 PHOT
-
Authors:
- Brandenberger, A J
- Publication Date: 0
Media Info
Subject/Index Terms
- TRT Terms: Coordinates; Data plotters; Distance; Photogrammetry; Photographs; Shape; Size; Theodolites
- Old TRIS Terms: Determination; Stereoscopic plotters
- Subject Areas: Geotechnology; Highways;
Filing Info
- Accession Number: 00229028
- Record Type: Publication
- Files: TRIS
- Created Date: Aug 15 2004 1:48AM