AVIATR - Titan Airplane Mission Concept, Proposed unmanned aerial exploration of Titan |
AVIATR - Titan Airplane Mission Concept, Proposed unmanned aerial exploration of Titan |
Apr 16 2010, 12:20 AM
Post
#1
|
|
Senior Member Group: Moderator Posts: 2785 Joined: 10-November 06 From: Pasadena, CA Member No.: 1345 |
The AVIATR mission concept is an unmanned aerial vehicle that would fly over Titan’s surface. It’s nominal one year mission would enable detailed high-resolution images of Titan’s diverse landscapes for better comparison to Earth’s geological processes. Selected regions could be imaged at resolutions near 30 cm/pixel, equivalent to current HiRise imaging of Mars. In addition, atmospheric sampling would allow a profile of Titan’s thick lower atmosphere and how it relates to Earth’s atmospheric processes and weather systems.
Further details of the AVIATR mission concept were presented at the Lunar and Planetary Sciences Conference 2010 and at Titan Through Time 2010. See: Barnes et al. LPSC 41 (2010) Abstract 2551. “AVIATR: Aerial Vehicle for In-situ and Airborne Titan Reconnaissance.” Freely available here: http://www.lpi.usra.edu/meetings/lpsc2010/pdf/2551.pdf And also: http://www.info.uidaho.edu/documents/2010%...18467&doc=1 -------------------- Some higher resolution images available at my photostream: http://www.flickr.com/photos/31678681@N07/
|
|
|
Jul 13 2010, 02:33 PM
Post
#2
|
|
Senior Member Group: Members Posts: 1018 Joined: 29-November 05 From: Seattle, WA, USA Member No.: 590 |
I think I see. Part of my confusion is that, in the computer biz, when we talk about the resolution of a screen, we always just mean the pixels. So, if I understand correctly, when you guys talk about resolution, you include all the factors that could degrade the image: the pixel scale, of course, but also atmospheric noise, diffraction, probably even noise in the electronics themselves. Beyond a certain point (all other things being equal) increasing the pixel scale will not improve resolution at all. And so the dispute you two are having is not over the actual hardware being used but over the effect of these other factors?
Ralph: When you talk about doing science below the pixel scale, are you talking about making repeated observations of the same thing and computing a higher-resolution model from that? That is, you have to depend on having a static target. Or do you mean something more complex? (I may be guilty of seeing Bayesian and Markov Networks everywhere these days.) ;-) --Greg |
|
|
Jul 13 2010, 09:08 PM
Post
#3
|
|
Member Group: Members Posts: 715 Joined: 22-April 05 Member No.: 351 |
Properly speaking, resolution should be interpreted in terms of what you want to detect. Haze, low contrast, size of structure (frequently referred to as 'scale'), etc. all can effect how finely you can discriminate what you want to detect. To give an example. I may want to image trees that are 10 m across in an image in which each pixel covers an area of 1x1 m. So, the pixel resolution is 1 m, but my object resolution is 10 m. If tree sizes varied, the smallest tree I could reliably detect would probably have a crown 2 m across. It's actually more complicated than this since the tree probably wouldn't be exactly centered right, and I'd end up with some pixels that are all tree and some that are a mixture of tree and background, making the tree id harder. So my best reliable resolution (i.e., smallest tree) is probably 3x3 m.
However, people who build optical and camera systems want to have a way to compare the theoretical capabilities of the hardware. Sometimes, lines per inch are quoted (I've seen this in camera lens reviews, which then ignores the grain of the film, which would be equivalent to the size and density of pixels in an electronic system). In planetary missions, the instantaneous field of view is often given, which describes the angle seen by an individual pixel. To get theoretical resolution, you need this information and the distance to the object being imaged. Computer monitor resolution is usually quoted as an area of pixels (e.g., 1600x1200 pixels), but the pitch between pixels is somewhat equivalent to the IFV in camera systems, but not exactly. Every camera forms images in an array of pixels x by y in size (with push broom cameras have a single line of pixels and spacecraft motion creates the y dimension). Image size can be quoted in x by y dimensions, but that says nothing about the resolution. You can put the same 1000x1000 CCD chip behind both a telescopic and a wide angle lens and get very different resolutions that cover very different areas on the surface The above is not my area of specialty, so others may add or correct. What is my area of specialty is sub-pixel interpretation for Landsat scenes. Each pixel of a Landsat scene has several 'colors' that represent key spectral ranges. (More technically, each landsat image is really several images, each of which was imaged with one filter.) If you know the dominant materials within a scene, you can use that knowledge to determine the approximate area that each material represents within the area imaged by an individual pixel. To continue with my tree analogy, if you know that everything in the picture is tree canopy or a soil background, you can model how much of the area covered by each pixel. The technique is called spectral unmixing. It sounds like similar approaches can be used with radar data. They key, though, is that you need to know a lot about the surface you are imaging. -------------------- |
|
|
Lo-Fi Version | Time is now: 24th September 2024 - 05:00 PM |
RULES AND GUIDELINES Please read the Forum Rules and Guidelines before posting. IMAGE COPYRIGHT |
OPINIONS AND MODERATION Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators. |
SUPPORT THE FORUM Unmannedspaceflight.com is funded by the Planetary Society. Please consider supporting our work and many other projects by donating to the Society or becoming a member. |