Posted on: May 13 2019, 08:28 AM | |
Junior Member Group: Members Posts: 64 Joined: 17-December 12 From: Portugal Member No.: 6792 |
<br />Thanks for that link, 4throck, I really enjoyed watching that footage... There are some interesting things on NASA's resource reels, and also on some vintage documentaries. Looking elsewhere, and to stay on topic, searching Youtube for "Surveyor 3" gets you: https://www.youtube.com/watch?v=E6yQfbFMBcY https://www.youtube.com/watch?v=3WFT5_jLLjU Both are very interesting There's much more about other missions if you know where to look, including some Pioneer video images, but that's better discussed on a specific topic about image sources I think. |
Forum: Lunar Exploration · Post Preview: #244723 · Replies: 248 · Views: 5943354 |
Posted on: May 6 2019, 09:48 PM | |
Junior Member Group: Members Posts: 64 Joined: 17-December 12 From: Portugal Member No.: 6792 |
NASA has good quality HD scans available on Archive.org.Here's some from Apollo 15: https://archive.org/details/Apollo-15_Onboa...ilm-Mags_EE.mxf There are some frame-rate conversion and black clipping issues on some videos, but it's a great source.Incredible potential for image processing here. |
Forum: Lunar Exploration · Post Preview: #244686 · Replies: 248 · Views: 5943354 |
Posted on: Jan 5 2017, 09:21 AM | |
Junior Member Group: Members Posts: 64 Joined: 17-December 12 From: Portugal Member No.: 6792 |
Some nice images on the arXiv PDF. There's potential for a small animation there |
Forum: Rosetta · Post Preview: #234031 · Replies: 1412 · Views: 1158435 |
Posted on: Dec 18 2016, 05:38 PM | |
Junior Member Group: Members Posts: 64 Joined: 17-December 12 From: Portugal Member No.: 6792 |
I have a few more images I can add for completeness sake. For example, this paper shows images 38 and 45: http://eaps4.mit.edu/research/papers/Travis_etal_1979a.pdf But again, the data if from early on the mission. |
Forum: Venus · Post Preview: #233795 · Replies: 8 · Views: 33103 |
Posted on: Dec 16 2016, 10:39 AM | |
Junior Member Group: Members Posts: 64 Joined: 17-December 12 From: Portugal Member No.: 6792 |
Just to say that I've updated my astronomy page and some links have changed. The Pioneer Venus images are now displayed with image number, code and date. Processing is minimal, just histogram equalization of the scans. There are a few more Pioneer Venus images online, but I've been unable to identify them. http://www.astrosurf.com/nunes/explor_pvenus.html |
Forum: Venus · Post Preview: #233765 · Replies: 8 · Views: 33103 |
Posted on: Dec 16 2016, 10:30 AM | |
Junior Member Group: Members Posts: 64 Joined: 17-December 12 From: Portugal Member No.: 6792 |
I think that the issues mentioned (jpg compression, limited dynamic, noise) may prevent identification of those "particles". Even if they are real, the images may not have enough data to characterize what we are seeing. |
Forum: Titan · Post Preview: #233764 · Replies: 18 · Views: 31170 |
Posted on: Dec 13 2016, 04:04 PM | |
Junior Member Group: Members Posts: 64 Joined: 17-December 12 From: Portugal Member No.: 6792 |
The image sequence (in chronological order) shows the lander's light dimming as time passes and the battery runs out. At least I remember reading something regarding the lamp Vs ambient light levels and that's the only noticeable change. Here's an official release with all the data: https://www.youtube.com/watch?v=sZC4u0clEc0 Once tried to use that difference in illumination to get some color, but that JPG compression is just too high. An interesting processing would be to properly de-block the images (also for Pathfinder or Galileo). |
Forum: Titan · Post Preview: #233715 · Replies: 18 · Views: 31170 |
Posted on: May 27 2016, 01:43 PM | |
Junior Member Group: Members Posts: 64 Joined: 17-December 12 From: Portugal Member No.: 6792 |
... I'm not sure I know of anyone else getting surface details with a telescope of this size. That darker detail, so well centered on the disk, seems a bit like a processing artifact. Or your secondary mirror ;-) Extreme processing on images so small (compared to the theoretical resolution) can be tricky. The limb's contrast with the dark background can be enough to create a "doughnut" or ring effect. But if you can get more images and do a rotation movie, I'd be convinced ;-) |
Forum: Jupiter · Post Preview: #230958 · Replies: 113 · Views: 235662 |
Posted on: Jul 31 2015, 02:13 PM | |
Junior Member Group: Members Posts: 64 Joined: 17-December 12 From: Portugal Member No.: 6792 |
Updated highres CIVA images published here: http://www.esa.int/spaceinimages/Images/2015/07 |
Forum: Rosetta · Post Preview: #224983 · Replies: 1412 · Views: 1158435 |
Posted on: Jul 31 2015, 02:06 PM | |
Junior Member Group: Members Posts: 64 Joined: 17-December 12 From: Portugal Member No.: 6792 |
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Forum: New Horizons · Post Preview: #224982 · Replies: 88 · Views: 356071 |
Posted on: Jul 27 2015, 04:03 PM | |||
Junior Member Group: Members Posts: 64 Joined: 17-December 12 From: Portugal Member No.: 6792 |
Left: generated noise Right: wild processing of the generated noise If you want to find it, a pattern always emerges. On this case, I tried to bring out "linear features" and behold they appear. I can make out a diagonal line across the top left half! If I started with a more complex image (with larger scale shadings for example) the resulting features would also be more elaborate. JPG compression artifacts, aliasing effects on scaling our even histogram manipulation will all generate noise. Just like Phil exemplified. The purpose of image processing is to remove or hide the noise, not to amplify it! To compare NH to HST, the first step it to reduce NH data to the same resolution as HST, and not the other way around. You get this (NH at bottom): Reasonable match to the top HST map, given that the wavelengths and phase angles are different. |
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Forum: Image Processing Techniques · Post Preview: #224841 · Replies: 31 · Views: 30738 |
Posted on: Jul 24 2015, 01:52 AM | |
Junior Member Group: Members Posts: 64 Joined: 17-December 12 From: Portugal Member No.: 6792 |
Agreed. In theory it works, in practice you'd need to calibrate the images (flat field, linearize the response, etc, etc). (Violet is always a tricky filter to deal with, since it should translate to both the Red and Blue channels. But that's really Voyager related so let's not discuss it here ;-) ) |
Forum: New Horizons · Post Preview: #224607 · Replies: 1286 · Views: 20556250 |
Posted on: Jul 23 2015, 11:57 PM | |
Junior Member Group: Members Posts: 64 Joined: 17-December 12 From: Portugal Member No.: 6792 |
I took the latest MVIC image, subtracted out all of the filtered color to obtain a green channel. My suggestion to get a green channel with real data would be to use the panchromatic image (Lorri). That one is the sum of all wavelength (of course, subject to the camera's response). To keep it simple, let's say that Lorri = R+G+B You add R + B from MVIC, convert to grayscale and subtract it from Lorri. You get G. (In theory you can use a similar tick to get red from Voyager's Violet and Orange channels....) The only trouble is that you need perfect registration and to compensate for camera response. |
Forum: New Horizons · Post Preview: #224601 · Replies: 1286 · Views: 20556250 |
Posted on: Jul 23 2015, 08:41 PM | |
Junior Member Group: Members Posts: 64 Joined: 17-December 12 From: Portugal Member No.: 6792 |
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Forum: New Horizons · Post Preview: #224580 · Replies: 1286 · Views: 20556250 |
Posted on: Jul 23 2015, 05:14 PM | |
Junior Member Group: Members Posts: 64 Joined: 17-December 12 From: Portugal Member No.: 6792 |
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Forum: New Horizons · Post Preview: #224561 · Replies: 1286 · Views: 20556250 |
Posted on: Jul 18 2015, 10:43 PM | |
Junior Member Group: Members Posts: 64 Joined: 17-December 12 From: Portugal Member No.: 6792 |
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Forum: New Horizons · Post Preview: #224184 · Replies: 1286 · Views: 20556250 |
Posted on: Jul 17 2015, 01:28 AM | |
Junior Member Group: Members Posts: 64 Joined: 17-December 12 From: Portugal Member No.: 6792 |
About the shadows, we don't know if they are projected into flat ground. If not, the shadows will look distorted, tilted, broken, etc. |
Forum: New Horizons · Post Preview: #223883 · Replies: 1286 · Views: 20556250 |
Posted on: Jul 17 2015, 12:04 AM | |
Junior Member Group: Members Posts: 64 Joined: 17-December 12 From: Portugal Member No.: 6792 |
I've uploaded an improved image. Since I've added noise, the SN in the image is lower. I'd be extra cautious with any small details there. The noise helps to mask the blocks, so that your brain is no longer distracted by them. But it can also "connect the dots" and create false details. |
Forum: New Horizons · Post Preview: #223874 · Replies: 1286 · Views: 20556250 |
Posted on: Jul 16 2015, 11:52 PM | |
Junior Member Group: Members Posts: 64 Joined: 17-December 12 From: Portugal Member No.: 6792 |
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Forum: New Horizons · Post Preview: #223870 · Replies: 1286 · Views: 20556250 |
Posted on: Jul 15 2015, 11:30 PM | |
Junior Member Group: Members Posts: 64 Joined: 17-December 12 From: Portugal Member No.: 6792 |
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Forum: New Horizons · Post Preview: #223677 · Replies: 1286 · Views: 20556250 |
Posted on: Jul 15 2015, 11:09 PM | |
Junior Member Group: Members Posts: 64 Joined: 17-December 12 From: Portugal Member No.: 6792 |
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Forum: New Horizons · Post Preview: #223674 · Replies: 1286 · Views: 20556250 |
Posted on: Jul 14 2015, 11:51 PM | |
Junior Member Group: Members Posts: 64 Joined: 17-December 12 From: Portugal Member No.: 6792 |
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Forum: New Horizons · Post Preview: #223403 · Replies: 1286 · Views: 20556250 |
Posted on: Jul 14 2015, 05:30 PM | |
Junior Member Group: Members Posts: 64 Joined: 17-December 12 From: Portugal Member No.: 6792 |
..it seems that the image was in fact colorized using higher resolution MVIC data than we have been seeing until now... Second that, there's some saturation variation and if you stretch the levels you get some white/pink areas related to different terrains. |
Forum: New Horizons · Post Preview: #223325 · Replies: 1286 · Views: 20556250 |
Posted on: Jul 14 2015, 03:46 PM | |
Junior Member Group: Members Posts: 64 Joined: 17-December 12 From: Portugal Member No.: 6792 |
Yes, doubtful. Highpass will bring out ring artifacts, and create the illusion of a brightness along the limb. On the other hand, the released image is not raw. Certainly there was a circular selection made around the planet, to bring the lightness of the disk up, while keeping the background of the frame black. Makes perfect sense for them to do that on an image that most people will see on TV, cellphone, etc, in well lit places. So it's that selection that you are seeing, not the atmosphere. At least that's my interpretation. |
Forum: New Horizons · Post Preview: #223304 · Replies: 1286 · Views: 20556250 |
Posted on: Jul 14 2015, 02:55 PM | |
Junior Member Group: Members Posts: 64 Joined: 17-December 12 From: Portugal Member No.: 6792 |
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Forum: New Horizons · Post Preview: #223289 · Replies: 1286 · Views: 20556250 |
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