SPACE.com -- Venus Revisited: Modern Technology Sharpens Images from Soviet Missions

Seen above is a topographic map made by Donald Mitchell using altimetry data from the Venera missions and NASA's Magellan mission. It shows the continent-sized highlands of Ishtar Terra, near the north pole of Venus. Photos: Courtesy Donald Mitchell

The Soviet Union's Venera 9 sent image telemetry for 50 minutes from Venus. It scanned 174 of the panorama from left to right, and then 124 scanning right to left. This image shows how Donald Mitchell improved the quality of the initial transmissions. Photos: Courtesy Donald Mitchell

Here is a section of a reworked Venera-13 image by Donald Mitchell. The raw data from Venera-13 and 14 is currently being processed. Photos: Courtesy Donald Mitchell

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	Venus Revisited: Modern Technology Sharpens Images from Soviet Missions By Leonard David Senior Space Writer posted: 06:30 am ET 22 April 2004

Subj:

From the mid-1970s into the early 1980s, the former Soviet Union succeeded in landing automated craft on the hellish surface of cloud-veiled Venus.

Decades later, imagery produced by several of the Soviet Venera series of craft have undergone reprocessing by an imagery specialist, yielding a clearer, crisper look at the eerie-looking landscape.

Donald Mitchell, a former image specialist for AT&T Bell Labs, has utilized new techniques on original telemetry broadcast from Soviet Venus lander craft.

Mitchell points out that the Soviet exploration of Venus, from 1961 to 1984, was an impressive effort that put to the test the fundamentals of interplanetary spacecraft design and remote sensing. Successful Soviet missions to Venus included 3 atmospheric probes, 10 landings, 4 orbiters, 11 flybys or impacts, and 2 balloon probes of the clouds, he noted.

Modernizing imagery

For his Venus work, Mitchell started with original digital data, applying corrective techniques that modernized the photos. His goal is preparing super-slick digital images that are up to snuff with todays sRGB standard -- an accepted default color space for the computer and Internet age.

"Most of the images one saw were derived from film recordings or scans of poor quality printed pictures," Mitchell told SPACE.com. "There are several things I believe can be accomplished by yet another go at the data," he said.

His work has paid off.

Using a variety of techniques, Mitchell has reconstructed much more flawless versions of the old Soviet Venus imagery. Furthermore, the optical aficionado is trying to recover accurate color of the Venusian terrain by studying the spectral response of Venera camera filters. Even the skylight spectrum that the Venera landers measured using onboard instruments is being taken into account.

"From their 1980s publications, you can see that the Russians understood the problem," Mitchell said. "But in the early 1980s they may have lacked the computer resources. Chartless camera calibration algorithms had not been invented at that time."

Challenge ahead

Mitchell said he is currently working on the higher quality images from Venera-13 and 14, starting from the original 9-bit Russian data. "I think those results will be considerably more interesting than the Venera-9 and 10 images."

Mitchell said that hes contemplating further work on the Venera imagery. A possible step, he said, would be an attempt to compute a super-resolution panorama based on multiple scans of the terrain on Venus.

"That is quite challenging because of the mechanics of the camera system. But I will give it a try someday," Mitchell said.

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