Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/JPLNEWS1/0402.PR

Text File | 1993-04-21 | 6KB | 114 lines

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P└OFFICE OF PUBLIC INFORMATION
JET PROPULSION LABORATORY, CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA.  TELEPHONE [phone]


FOR RELEASE:  AM's, Tuesday, August 9, 1966


     JPL COMPUTER PROCESS BRIGHTENS SURVEYOR MOON PICTURES


┴┴         PASADENA, Calif.--The sparkling success of Surveyor I
in taking television pictures of the Moon's surface has been
further enhanced by a computer process developed at Caltech's
Jet Propulsion Laboratory.
         Clear as most of Surveyor's 11,150 pictures were, the
JPL process, applied to a dozen of the most scientifically
exciting shots, brought out detail down to one-half millimeter
-- or one-fiftieth of an inch -- in height.
         Some the enhancements apparently doubled the
observable details.  The flow pattern of dirt clods in one
enhancement, for example, enabled scientists to figure that
they were scattered by the landing impact of one of Surveyor's
footpads.
         The results were not toally unexpected.  Moon photo-
graphs from the last three Ranger spacecraft missions had been
intensified by the same process to show bumps three inches high
on the lunar surface.  The same technique was applied to Mariner
IV pictures of Mars to bring out interesting details of that
planet last year.
         These sharper prints are produced by a computerized
system which corrects distortions and improves resolution in  ▄h▄îoriginal photographs taken by television cameras.  The system
was developed by Dr. Robert Nathan, who led the JPL video
digital (computer) data reasearch for the National Aeronautics
and Space Administration.  Robert Selzer was in charge of
Surveyor picture enhancement.
         Quality enhancement is steadily being upgraded by
computer research engineers at JPL, which the California
Institute of Technology operates for NASA.  Basically, they
employ a large computer (IBM 7094) to filter out noise and
frequency distortions in radio signals which send the pictures
through space.
         Mathematicians and computer programmers devise precise
formulas and reduce them to computer instructions to remove
blemishes from pictures.  Other procedures stretch picture
contrast--that is, make dark areas darker and light ones
lighter.  The process cannot add features not originally
photographed and recorded, but it clarifies details to an
impressive degree.
         The result has been a dramatic improvement in both
lunar and Martian picture resolution since Ranger VII first
video-scanned the Moon for the United States in July, 1964.
"We are removing the fog in our pictures of our planetary
system," says Nathan.
         Space scientists use the improved pictures for mapping,
as well as interpretive analysis.  Enhanced Ranger pictures
helped Surveyor project leaders to choose landing sites along
the Moon's Equator.  Similarly, Surveyor enhancements should aid ▄h▄îscientists to select the best Moon site for landing U. S. astro-
nauts in the Apollo program.
         Computer enhancement began in 1963 after Nathan saw
Russian pictures of the Moon's far side.  "I was certain we
could do much better," he recalls.  "It was quite clear that
extraneous noise had distorted their pictures and severely

handicapped analysis."
         During 1964 and 1965, Rangers VII, VIII and IX took
more than 17,000 lunar pictures.  On each mission, six tele-
vision cameras transmitted picture data over the 235,000-mile
distance in a matter of seconds.  The Ranger series produced
picture resolution up to 2,000 times better than Earth-based
photos of the areas where the Rangers impacted.
         Another JPL scientist, Thomas Rindfleisch, developed a
technique for utilizing the unique reflective properties of the
lunar surface to produce topographic maps via the computer
process.
         The single vidicon camera aboard Mariner IV took and
recorded 22 pictures of Mars in 26 minutes on July 14, 1965.
Picture resolution was two miles, although snapped from
distances of over 7,400 miles.  Playback transmission of each
picture involved sending 240,000 pieces of information over 8
and 1/2 hours.  Mars was 134 million miles away from the JPL
Deep Space Network receiving stations at Goldstone, Calif., and
abroad.
         Before the JPL team tackled the problem, space photo
data analysis yielded about 5 per cent of the maximum potential; ▄h▄înow it is approaching 95 percent.  Much of the computer hardware
development was done by Fred Billingsley, computer engineer, and
John Morecroft, Mariner IV data specialist.
         Some Ranger photographs have been reprocessed six or
more times.  Preliminary Mars picture processing lasted five
months.  During this period more than 3,000 computer instruc-
tions were written to correct flaws and 1,500 prints were made.
From these came a file of 300 prints, which are still be
upgraded.
         The technique employs several steps.  The vidicon
signals from the spacecraft are recorded on magnetic tape with
each impulse registered as binary digits, or bits, in computer
language.  Each six bits on the tape determines the darkness of
a point.  The digits (010101, 101110, etc) represent 64 shades
from white to black.
         The digital tape is fed into a computer which reconsti-
tutes the image according to the points and lines of the vidicon
system used.  The computer compares lines, picks out and elimin-
ates noise in the transmission.  After electronic correction,
data are transferred onto another magnetic tape.  This is run
through a film reproducer for the corrected photograph.
         Moreover, a new computer system is being set up to
handle eight bits instead of six.  An eight-bit system would
provide 256 shades of gray in pictures and also speed up
processing.  Billingsley expects the stepped-up system to be
ready for 1967 Surveyor lunar scanning and the 1969 Mariner
probe of Mars.                                      402-8/1/66