98 PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING, 1976 
  
      
i i : = en S SE 
^ Sn. ve E 
duse 
NOMINA SENS NS ® = a v sn 
Fic. 3. Enlarged movie frames representing various stages of the experiment. 
each frame. The measurements were performed on an NRC monocomparator using a copy of 
the original 16 mm movie film. 
Various tests were made to determine the accuracy of the obtained information. The 
following standard errors were found: 
for the car position: I, £m, lom 
m, — 7 cm 
for the car orientation: me = M, = 2.4' (minutes of arc) 
m,, = 3.9' (minutes of arc) 
The x and y coordinates are parallel to the image plane and the z coordinate is parallel to the 
optical axis of the camera. The angles k, ¢, and o represent the yaw, pitch, and roll of the 
vehicle, respectively. 
Uncontrolled experiment. The Photogrammetric Research Section has repeatedly become 
involved in the evaluation of uncontrolled non-metric photography in connection with aircraft 
accidents. In these cases single frames or movies were provided and either the absolute 
aircraft position(s), or changes in the aircraft position from frame to frame, were asked for. 
In each case only a single camera of unknown make had been used. Therefore, the interior 
orientation was unknown. In addition, the camera position was only approximately known. 
Since a crashing aircraft approaches the surface of the earth, a camera following its path may 
eventually show the aircraft surrounded by topographical features suitable to derive, by 
spatial resection, both interior and exterior orientation. This, however, necessitates first the 
determination of coordinates for suitably located topographical features, usually within a local 
net (Figure 4). 
Once interior and exterior orientation have been determined for each photograph, from 
control point coordinates and measured photograph coordinates for these points, it is possible 
not only to project the object bundle back into space but also to intersect the object bundle 
with suitable planes. One such plane, perpendicular to the chosen direction of the local 
coordinate grid and approximately 1 km away from the determined camera station, was used to 
compute projected coordinates for the aircraft. These coordinates X, Z were then also derived 
from the given airplane dimensions (Figure 5):