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#21
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On Sun, 09 Sep 2007 10:36:35 -0400, NoneYa
wrote: We can take pictures of objects on the Earth from space that are 2 inch's wide. We can take pictures of objects on Mars that are 12 inches wide. Why can't we find a wrecked airplane in Nevada?? A place that is mostly dirt and sand with very little vegetation? Makes no sense Makes a lot of sense to me. Tain't all that easy even with image comparison. Too many variables, irregular shaped objects, and changing landscape along with no recent data/images for a base line. We can easily find lots of things when we are looking at either a small area for something specific of any area where we look for "anything", but not something specific in a very large area. That is extremely difficult. When it comes to pattern recognition, computers are very good at looking for some specific shape, but not good at finding that shape when it's been altered. The algorithms for complex pattern recognition are very sophisticated and typically take lots of computing horsepower. On top of that if there is any brush around, airplanes can be extremely difficult to spot even from 500 or a 1000 feet. A Bo went down between here and MOP a few years back. That area runs probably between 50 and 100 people per square mile. They put it between two trees and walked out. The FAA inspectors couldn't readily find the plane so to save time the two guys took them back in and as I understand it still took them a few hours to find it. |
#22
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yeah he's certainly not evading but the big question is "why didn't his elt
go off ?" what scenarios fit this ... he experienced a health problem and got the plane down ? doesn't seem like an experienced pilot like him would forget to set it off by hand after a forced landing .... Do they sometimes fail to go off on impact ? "Matt Whiting" wrote in message ... Thomas Borchert wrote: Newps, That's a bad analogy, we're not looking for one airplane in a sea of other planes. Remove all the planes in the picture except one. Now try and find the one plane. Hey, "we" can't even find Osama when "we" have 6 years to try (in a similar landscape, I might add). True, but I don't think Fossett is trying to not be found. :-) Matt |
#23
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On Mon, 10 Sep 2007 15:27:35 +0900, "donzaemon" wrote:
yeah he's certainly not evading but the big question is "why didn't his elt go off ?" what scenarios fit this ... he experienced a health problem and got the plane down ? doesn't seem like an experienced pilot like him would forget to set it off by hand after a forced landing .... Do they sometimes fail to go off on impact ? As someone else posted, severe crashes can sever the ELT antenna. Sadly, it's the scenario that best fits the apparent lack of signals from either his ELT or his wrist-mounted PLB. Ron Wanttaja |
#24
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Bob,
Our $40G/year intelligence expenditure mistakenly identified WMD in Iraq. Not really. They wanted to see WMDs, because the politicians wanted them to see them - and so they did. The government paid, and got what it paid for. -- Thomas Borchert (EDDH) |
#25
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Donzaemon,
Do they sometimes fail to go off on impact ? More often than sometimes, it seems. If they are not 406-Mhz-units, that doesn't help either. -- Thomas Borchert (EDDH) |
#26
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donzaemon wrote:
yeah he's certainly not evading but the big question is "why didn't his elt go off ?" what scenarios fit this ... he experienced a health problem and got the plane down ? doesn't seem like an experienced pilot like him would forget to set it off by hand after a forced landing .... Do they sometimes fail to go off on impact ? Yes, they do fail sometimes to go off on impact. Matt |
#27
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Now you are talking about something I know something about. I have
written the image search software that pretty much has 90% of the US intelligence market. There are two things you need: 1. Satellite tasking over the area. 2. Enough dedicated eyeballs watching the monitors who know what to look for. Believe me, even the commercial satellites such as Digital Globe have enough information (time / location) and if DG wanted to collect imagery, they probably could over a weeks time do it. However, whose going to pay them? Satellite time costs money. It's not just a bunch of data sitting in a google earth like database of the entire world. Things are collected as there is a demand. |
#28
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For Steve's sake, I hope he's still hiding in the back of the hangar
with Paris. |
#29
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On Sep 9, 7:36 am, NoneYa wrote:
We can take pictures of objects on the Earth from space that are 2 inch's wide. We can take pictures of objects on Mars that are 12 inches wide. Why can't we find a wrecked airplane in Nevada?? A place that is mostly dirt and sand with very little vegetation? Makes no sense The high quality Google Earth pictures are all done with aircraft. Googe has had aircraft up to update the search area so you can help search right now on Google Earth. |
#30
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On Sep 9, 12:01 pm, Ron Wanttaja wrote:
On Sun, 09 Sep 2007 10:36:35 -0400, NoneYa wrote: We can take pictures of objects on the Earth from space that are 2 inch's wide. We can take pictures of objects on Mars that are 12 inches wide. Why can't we find a wrecked airplane in Nevada?? A place that is mostly dirt and sand with very little vegetation? Makes no sense No, you just have to understand the realities of the process. Imagine a satellite snaps a picture of Wittman Field during Airventure. Assume it has a high enough resolution to allow individuals to be recognized. There are 400,000 people on the grounds at the time...and you want to find one particular person. You don't know where he was at the time the photo was taken That means you will have to zoom in on, individually, each person visible on the image. With average luck, you'll have to examine 200,000 individuals before you find your friend. (Heck, here's an aerial photo of Oshkosh: http://www.airventure.org/2007/media...al_from_SW.JPG ...just try to COUNT how many people are visible) Keep in mind, too, that this isn't a mug shot...unless they were pre-warned, the people in the image won't be looking at the camera. If you take the picture from directly overhead, all you see it a bunch of caps. But even if the picture was taken obliquely, some folks will be turned away from the camera, or holding a cup to their mouths, blocked by other people, inside the exhibition halls, or using a portajohn, or lying under a tree, or even unexpectedly off the grounds entirely. The problem is analogous to the Fossett search. Let's assume the camera gives the equivalent of viewing an area 500 feet by 500 feet. That is about .01 square mile. With a 10,000 square mile search area, that gives one million 500x500 foot blocks to examine. And remember all those persons who were turned away or kneeling down, tieing their shoes, in the Oshkosh picture? After nearly two weeks of an intense air search, the lack of success is probably because Fossett's Decathlon doesn't strongly resemble an aircraft any more. It's undoubtedly crumpled, it's quite possibly burned. By now, it's probably dusted with the "dirt and sand" you refer to, making it blend in even better. The persons who would examine the imagery wouldn't be looking for the big white "+" of wings and fuselage, they'd be looking at every apparent bush, every apparent rock, to guess if sometime, in the past, it just may have been an airplane. How long should they examine each block? If each takes two minutes, we're talking well over 30,000 labor hours. Every shadow on the image might hide wreckage, so you'd better have another set of photos taken at a different time of day. AND look at those. Finally, finding hidden objects in imagery is a *military* specialty your typical Ikonos analyst doesn't practice. If you want experts to look for the plane, you're going to have to go to the government...and those folks are pretty busy on some pretty important tasks. Ron Wanttaja There are techniques other than straight visual images for detecting objects, although I am not sure if any of them are being used in this context. Examples are infrared hyperspectral and polarimetric imaging. |
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