8
January 2016
PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING
Due to the arrangement
shown in Figure 2, five
kinds of image distortion
were present:
1) Panorama distortion.
The cameras rotated
around the horizontal
axis during exposure.
2) Distortion attributable
to Earth curvature at
satellite heights.
3) Camera tilt.
4) Satellite motion
during exposure while
scanning a strip.
5) Image motion
compensation
(introduced to reduce
4)
The first three are most
significant, the last two
are less significant. Images
on 70 mm high-resolution
film, were stored for release in flight, descent by parachute,
and capture by aircraft over the Pacific Ocean. (Corona, 2015).
The photographic resolution was almost equal to later satellite
imaging systems. After declassification, the films were first
copied and later scanned for users at 7.0 or 14.0 microns and
made available on the USGS website with search software for
locating the image paths. A typical set of paths looks like:
They are georeferenced using the 1960 Hough ellipsoid
(Sealander, 1996; Fischer, 1959). This adds positional errors
if the USGS meta-data is referenced to the WGS84/GRS80
ellipsoids.
The cameras and distortion correction hardware were
designed and built by the ITEK Corporation (ITEK 1957-
1996), a spin-off from Boston University, financed by the CIA
and NRO. The production teams were directed by Frances.
Figure 2. Cross-section of the camera and film compartments showing the rotating, tilted high resolution
lens systems in KH 4-B.
J. Madden (1997). The senior scientific adviser was Claudius
(Claus) Aschenbrenner (CV n.d.) curriculum vitae no date.
Aschenbrenner, born on March 21, 1894, was of the second
generation of German photogrammetrists. He studied with
S. Finsterwalder and O. von Grüber in Munich. In the 1920s
and 1930s, after World War I, he developed and flew designs
for panoramic cameras. From the mid-1930s until the end
of World War II, he directed the wide area photogrammetry
section of the Luftwaffe as a professional officer, rising to the
rank of full colonel in 1943.
After World War II, under the Program “Operation Paperclip”
(Operation Paperclip 1945), Aschenbrenner was taken to the
United States and assigned to Wright Field, Ohio. He was
later transferred to the Boston University Optical Research
Laboratory, the predecessor of ITEK, as Senior Scientist. He
retired on January 9, 1965 at the aged of 72. It is not known
exactly when he died.
Aschenbrenner’s career can be followed in the German military
photogrammetry personnel archive (Schrödter 2002). His
patents for the KH4 cameras and Gamma Rectifier distortion
correction hardware were assigned to ITEK (Aschenbrenner
CV n.d.). These patents include neither classified details nor
mathematics.
Earlier, Aschenbrenner designed a projection transforming
printer, the EN-71, for wide area panoramic camera images
made from the U.S. Army USD-5 drone aircraft. (ITEK
Panoramic Progress I 1961) A publication appeared in the
open photogrammetric literature, (ITEK Panoramic Progress
II 1962).
Figure 3. Image strips (each ca. 200km x 15 km) no distortion
correction, from Central Armenia.
