Espritmodel.com Telemetry Radio
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Old Apr 06, 2012, 12:08 PM
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Originally Posted by gnofliwr View Post
In Destination Imagination/Odyssey of the Mind, Manager's/Coach's training that's a sample problem given to the managers/coaches. One of the answers we got, once, with respect to the Empire State Building was, "sell the barometer, buy a ticket on the elevator to the observation deck and read the height off of the commerative plaque."

...
- Roger
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Go to the building supervisor.."I'll give you this nifty barometer if you'll tell me the height of the building".
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Old Apr 06, 2012, 12:12 PM
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You'd have to tell the utility what is an object of interest and its orientation in the mass of pixels any image is.
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Old Apr 06, 2012, 12:17 PM
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Wow a lot more complicated than I imagined. Too bad I'm terrible at math. Can I connect an eagle tree altimeter to my hobby zone super cub even if it is only 4 channel?
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Old Apr 06, 2012, 12:30 PM
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This one? It's practically weightless!
http://www.eagletreesystems.com/Stan...standalone.htm
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Old Apr 06, 2012, 02:13 PM
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Here's another take on it, http://en.wikipedia.org/wiki/Photogrammetry

Page includes links to both paid softwares and free software to help solve this dilemma from an image.
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Old Apr 06, 2012, 05:59 PM
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Originally Posted by Sparky Paul View Post
You'd have to tell the utility what is an object of interest and its orientation in the mass of pixels any image is.
Yes, I think it would be sufficient to click on any three non co-linear pixels and to type in the ground-based distances between them. The corners of a rectangular warehouse or sports field would be a common sight in many suburban RC photos/stills.

The angle of incidence can then be calculated from the relationship of those pixels with respect to each other. For example, if they're colinear in the image, and yet the user-entered distances say they're not, the photo was taken by an ant at ground level

The utility would need to be told the camera focal length + sensor size (FOV) if it's to then calculate the distance to the object along its angle of incidence according to its relative size within the photo.

It certainly wouldn't be anywhere near as sophisticated as those apps linked to by the Wikipedia page, but for RC purposes it wouldn't need to be. We're not so much interested in auto-generating vast 3D point clouds from our images, but rather just an estimate of object distance.
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Old Apr 06, 2012, 07:31 PM
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Before the days of GPS, that's how aerial photogrammetry was done.
On the L-1011 program, we had a couple of Photosonics 35mm cameras in the nose cone in airplanes which had no radar installation in the nose.
We installed a lot of plywood targets extending a couple miles from the approach end of the instrumented runway which had localizer and glideslope transmitters, when testing and certifying the Autoland™ system.
Film readers in the data reduction group would view the images in calibrated viewers and select the targets to use for any data run.
The computer would then do a lot of computing to determine where the plane was relative to the runway.. distance from,above and off-center, and the pitch, roll, yaw angles and the airspeed.
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Old Apr 06, 2012, 07:45 PM
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That's fascinating info, thanks Sparky Paul.

"L-1011 program" = Lockheed TriStar? Is this 1960s-vintage technology and methodology? I doubt the pure maths and trig has improved significantly, but I find it interesting that a single lowly PC could automate so much tedious calculation and graph drawing.

The "bug strike" label on the photo - someone had a sense of humour
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Old Apr 06, 2012, 07:58 PM
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Originally Posted by tpatchin2 View Post
I have on board video from my plane and I wanted to know if I could measure my altitude from the footage.
I should read better before posting advice but there's a formula....easy way is just stick a GPS on it
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Old Apr 06, 2012, 08:04 PM
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We had 1/2 an entire floor in Bldg 602 devoted to only the data analysis computer!
Prolly a laptop computer today has more capacity and computing power! And no extensive air-conditioning needed.
Any jogger today can buy a GPS equipped watch which can compute and record all this stuff without all the calibration rigamarole!
But ya gotta have the targets identified for the casual user today, with our video cameras flying around out there. There's still math involved.
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Old Apr 07, 2012, 06:55 AM
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Originally Posted by tpatchin2 View Post
I have on board video from my plane and I wanted to know if I could measure my altitude from the footage.
You are about 467 ft 520 maximum.. that is my guess.

I would go again with the Eagle tree. Well protected. no questions asked. spend the $4.00 extra.
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