VEGA MISSION

International project VENUS-HALLEY was devoted to Venus exploration from the orbiter and from the lander and to Halley Comet investigation from the flight-by probe. Two interplanetary probes were launched in 1984, they have retained the lander and the balloons on Venus and investigated Halley Comet during the flight-by in March,1986. The on-board TV system produced about 1500 images, including the close-up pictures of the comet nucleus from a distance ~ 8000 km.

The on-board TV system was created in international cooperation of the scientific and industrial facilities from the USSR, Hungary, France and Czechoslovakia. The system has provided the comet observation as well as the nucleus search and tracking. The TV system was located on the 3 axis platform, controlled by the system itself.

TV data were processed by international team, including the USSR, Hungary, France, GDR and USA scientists. The basic steps of data acquisition and preprocessing were performed in IKI using the image processing computer system, based on PDP11/40 compatible host. The Image Processing SW for this system was developed by Planetary Data Image Processing Lab personal under RSX11M.

Some image processing results are presented below.

The noise reduction. The linear structure noise (c) is cleaned up from the source image (a) with using a image decomposition procedure at space domain. The CCD flat field defect - 2 horizontal lines in the middle if the source image is corrected also. The result is (d) image.

The nucleus shape definition. After the noise correction and the definition of the nucleus limb, the separate analysis of the nucleus image provides to stretch of nucleus brightnesses from [-3sigma,3sigma] to [-128,128] and to see the nucleus details.

The jets definition. The analysis of Fourier spectrum (a) provides the "beams" extraction from the spectrum and the construction of the composite image with the nucleus and the jets.

The nucleus size definition. Based on the procedures for 2 previous images the composite images are created. The scale shows the nucleus size.