VENERA-10 image processing by Donald Mitchell

Venera 10 sent image telemetry for 44.5 minutes, before burning up. It scanned a 17º section, then 184º and then 63º.
The upper image is the raw 6-bit telemetry, about 115 by 512 pixels. Automatic gain control and logarithmic quantization were used to handle the unknown dynamic range of illumination.

The raw image was converted to optical density according to Russian calibration data, then to linear radiance for image processing. It was interpolated with windowed sinc filter to avoid post-aliasing (a "pixilated" appearance), and the modulation transfer function ("aperture") of the camera was corrected with a 1 + 0.2*frequency**2 emphasis. This was then written out as 8-bit gamma-corrected values, using the sRGB standard gamma of 2.2. Some of the telemetry bars from the long panorama were filled in with image data from the other two sections.

The bottom image is digitally in-painted, using Bertalmio's isophote-flow algorithm, to fill in missing data.

Copyright © 2003 by Donald Mitchell. Reproduced with permission.