Venera-13, Venera-14 Lander Images, Images generated from raw digital telemetry |
Venera-13, Venera-14 Lander Images, Images generated from raw digital telemetry |
Guest_DonPMitchell_* |
May 5 2006, 07:40 PM
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Guests |
Here are images I generated from the 9-bit Venera-13 and Venera-14 data. Most of the work was spent combining three or four transmissions from the spacecraft, each with an independent set of digital noise. In some cases, scrambled regions of images were restored by recalculating the 10th parity bit, and shifting the bit stream. In particular, I resurrected a new section of the image on Venera-14 Camera II on the left side. I managed to distill out one very high quality copy of the full transmission from each of the four cameras.
Next, there is the problem of linearizing the camera response. The camera response curves published in Cosmic Research are wrong, or at least they do not extend into the darker range where a lot of the actual Venus imagery lies. You can prove they are wrong from the calibration wedges, viewed through the four different filters. Correct generation of true log response would result in wedge profiles that are exactly offset from one another. Some recent work on camera self-calibration in the computer-vision community points the way to reconstructing response curves, and when applied to the Venera images, the result is very pleasing. Round objects, like the elbow joint of the penetrometer, look round, not flat, details in shadows appears out of the blackness of the original Russian images, and some additional hills on the horizon appear out of the formerly white sky. The full transmission consisted of several passes of the camera scanner, back and forth, across the scene. These four panoramas are combinations of up to five black-and-white images (clear filter), and a number of red, green, and blue-filter images. In Lab color coordinates, I extracted the ab channels from the red/green/blue images, and added them to the much higher quality B/W images. You can see that when making scans through the clear filter, the camera covered a wider area, the uncolored regions are just where the RGB data did not exist. Most of the blue images are black, due to a sudden drop-off in the camera response. There are probably a few areas near the bright horizon where the real RGB ratio can be extracted...a project for someone someday. I've been too busy with my book and my company in Seattle to completely finish what I wanted to do. The color is still not correct on any Venera surface images. But the color filters in the camera were balanced with gray filters to be somewhat correct. I am awaiting one last key piece of data -- the spectral response of a color filter that was in front of the calibration wedge. With that in hand, an absolute color calibration would be possible. Venear-13, Camera I (short program): Venera-13, Camera II (long program): Venera-14, Camera I: Venera-14, Camera II: |
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May 8 2006, 05:38 PM
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Junior Member Group: Members Posts: 40 Joined: 20-March 06 Member No.: 720 |
How will it really look when i am standing on the surface of Venus? Like grey or like a orange color.
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May 8 2006, 05:50 PM
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Dublin Correspondent Group: Admin Posts: 1799 Joined: 28-March 05 From: Celbridge, Ireland Member No.: 220 |
How will it really look when i am standing on the surface of Venus? Like grey or like a orange color. It might look orange for a while but if you could stay there for a while your eyes would adjust and you would begin to find the orange increasingly less noticable. You can see a limited similar effect by wearing 3D anaglyph specs for an extended period of time and then taking them off. If you alternately close one eye and then the next everything will appear to be alternately blue\red tinged. |
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May 8 2006, 05:58 PM
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Senior Member Group: Members Posts: 2454 Joined: 8-July 05 From: NGC 5907 Member No.: 430 |
It might look orange for a while but if you could stay there for a while your eyes would adjust and you would begin to find the orange increasingly less noticable. You can see a limited similar effect by wearing 3D anaglyph specs for an extended period of time and then taking them off. If you alternately close one eye and then the next everything will appear to be alternately blue\red tinged. Remember when they used to claim that the Venusian atmosphere was so refracted that you could technically see all the way around the planet and right to the back of your head (or whatever special helmet was shielding it)? http://www.cosmographica.com/gallery/portf...fraction%20.htm -------------------- "After having some business dealings with men, I am occasionally chagrined,
and feel as if I had done some wrong, and it is hard to forget the ugly circumstance. I see that such intercourse long continued would make one thoroughly prosaic, hard, and coarse. But the longest intercourse with Nature, though in her rudest moods, does not thus harden and make coarse. A hard, sensible man whom we liken to a rock is indeed much harder than a rock. From hard, coarse, insensible men with whom I have no sympathy, I go to commune with the rocks, whose hearts are comparatively soft." - Henry David Thoreau, November 15, 1853 |
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May 8 2006, 07:13 PM
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Junior Member Group: Members Posts: 40 Joined: 20-March 06 Member No.: 720 |
Remember when they used to claim that the Venusian atmosphere was so refracted that you could technically see all the way around the planet and right to the back of your head (or whatever special helmet was shielding it)? http://www.cosmographica.com/gallery/portf...fraction%20.htm Why is the refraction and the distortion of the Venus surface and atmosphere not visible in the venera images? |
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May 8 2006, 07:29 PM
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#6
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Dublin Correspondent Group: Admin Posts: 1799 Joined: 28-March 05 From: Celbridge, Ireland Member No.: 220 |
Why is the refraction and the distortion of the Venus surface and atmosphere not visible in the venera images? Quoting Don from his second or third post: QUOTE The camera is a photo multiplier tube, some fancy optics and a mechanical scanner. Don't laugh, a PMT is the absolute best light measuring device known to man, so the image quality was amazing. The mirror sat inside a 1-centimeter thick cylindrical quartz window, and inside the camera was a special lens that inverted the effect of the refraction of the window. (Russians know their optics!) I reckon it's likely that any additional refraction effects caused by the different refractive indices of the inner and outer atmospheres was included in that bit of optical wizardry. Other than that the only distortion would have resulted from temperature gradients in the external atmosphere whichare highly unlikely to be significant given the fairly short range covered. |
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