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There Are Giant Camera Resolution Test Charts Scattered Across the US
- rikacomet 14y agoThey could have made it a bit more interesting, by coding a secret short message into them (yawn). But nonetheless, a interesting article.
- mgeraci 14y agoHere's a google maps link to one of the charts mentioned, on Edwards Airforce Base: https://maps.google.com/maps?q=Edwards+AFB,+East+Kern,+Kern,+California+93523&hl=en&ll=34.834087,-117.759426&spn=0.004412,0.008256&geocode=FUXbFAIdoWP4-A&hnear=Edwards+AFB,+East+Kern,+Kern,+California+93523&t=h&z=18 https://maps.google.com/maps?q=Edwards+AFB,+East+Kern,+Kern,...
- SoftwareMaven 14y agoFascinating that there are air craft relics near the charts. I can only imagine that is part of the calibrating: so they can tell how large an aircraft is and what resolution they get for the size.
- _djo_ 14y agoIndeed, plus one of the aircraft is one of only two remaining examples of the X-21 [0]. I suspect the other is also derelict on the range somewhere. http://en.wikipedia.org/wiki/Northrop_X-21 http://en.wikipedia.org/wiki/Northrop_X-21
- WorkingDead 14y agoCan we derive the implied resolution of government satellites by the test charts?
- jgrahamc 14y ago"Even satellites can utilize the charts. Here’s a chart as seen by the satellite used for Google Maps" It's not clear that that is a satellite photograph. Just because it was taken from above it doesn't mean a satellite did it. Mapping services (such as a Google's) do a disservice to call all this overhead photography 'satellite'. It's the sort of looseness that causes people to think cellular telephones also talk to satellites.
- badgar 14y ago> It's the sort of looseness that causes people to think cellular telephones also talk to satellites. Anyone who hasn't heard of a "cell tower" in 2013 just doesn't care about what makes the phone go. Cell phones have been around, talking to towers and not satellites, for decades. You can't help everyone.
- aw3c2 14y agoI just spoke to someone who thought that internet connections from the US to Europe go via satellite because there is so much water in between and you cannot just put a cable there. The cables are amazing (baffling even) but come on, they've been there for 150 years!
- jonknee 14y agoIt's not that far off, there is a ton of satellite photography in Google Maps. It's the other way around, but satellites talk to cell phones and I don't fault people for not knowing it's one-way.
- brudgers 14y agoThrow away business idea: QR codes for large tract real estate listings.
- stevenrace 14y agoThe prerequisite being a 'Maps' site with <weekly aerial updates. While relatively plausible today (a few styrofoam drones, camera arrays, pay fer acre for 'crowdsourcing', ...)[1], the legal woes are frightening. [1] 'relatively plausible' in relation to 'cubesats' and other aerospace driven monitoring.
- brudgers 14y agoA lot of real-estate sits for years. Weekly photos aren't really necessary.
- cynwoody 14y agoHow about just a large For Sale with an 800 number? If the property is under an approach to a busy airport. The audience being, of course, all those bored folks in window seats with electronics turned off below 10,000 feet. Design your sign. Slice your image into two or three horizontal stripes. Then email your slices to one of those vinyl banner sign companies, to be printed on 8' x 50' strips.
- brudgers 14y agoOne of the features of real-estate development is that a lot of research tends to be done anonymously to avoid tipping one's hand. In addition, many tracts of interest are not near airports, etc.
- bhauer 14y agoAny idea why some of them, especially the images from EAB, appear to cast shadows? That is, the white blocks appear to be bordered by black.
- NelsonMinar 14y agoThe source for this PetaPixel article is the Center for Land Use Interpretation, a really neat organization. http://www.clui.org/newsletter/winter-2013/photo-calibration-targets http://www.clui.org/newsletter/winter-2013/photo-calibration...
- biot 14y agoAlso, large compasses about 1km in diameter: http://goo.gl/maps/6wTtb http://goo.gl/maps/6wTtb
- Raphael 14y agoIf it's a compass, then why is it 20 degrees off?
- jonburs 14y agoThe magnetic north pole isn't in the same spot as the geographic north pole -- see http://en.wikipedia.org/wiki/Magnetic_declination http://en.wikipedia.org/wiki/Magnetic_declination.
- taejo 14y agoDoes ATC use magnetic bearings?
- rory096 14y agoYes. This is why runway numbers (which are the heading with the last digit removed) are known to change from time to time. Aviation charts also display the variation between magnetic and true north. (See the purple dashed lines with 14/15° W http://skyvector.com/?ll=40.55464932694554,-70.94216669067579&chart=15&zoom=4 http://skyvector.com/?ll=40.55464932694554,-70.9421666906757... )
- _djo_ 14y agoThose aren't for the same purpose, they're for test pilots to use when landing on the lakebed runways that you can see next to the compass. Both the X-1 and X-15, amongst many other experimental planes, landed on the lakebed rather than on conventional runways at Edwards AFB.
- sargun 14y agoWhy did they land on the lake bed as opposed to runways?
- gonzo 14y agofiducials, not so much for a 2-D 'where', but to help deal with the blurring (http://what-if.xkcd.com/32/ http://what-if.xkcd.com/32/)
- stevenrace 14y agoIs this test pattern in use in other known research? Most of the test patterns I've encountered in using 'OpenCV' [1], 'laser scanning'[2], and 'structured light scanning' [3] have used equal sized geometric shapes. Not increasing in scale, so maybe that's useful. [1] http://graphics.stanford.edu/~vaibhav/projects/calib-cs205/calibimg.png http://graphics.stanford.edu/~vaibhav/projects/calib-cs205/c... [2] http://www.david-laserscanner.com/wiki/_media/user_manual/screenshot_calib_pattern1_small.jpg http://www.david-laserscanner.com/wiki/_media/user_manual/sc... http://www.sciencedirect.com/science/article/pii/S0143816607000991 http://www.sciencedirect.com/science/article/pii/S0143816607... [3] http://opticalengineering.spiedigitallibrary.org/data/Journals/OPTICE/22111/053604_1_5.png http://opticalengineering.spiedigitallibrary.org/data/Journa...
- Cushman 14y agoDon't think spatial calibration, think eye chart: https://www.google.com/search?q=eye+chart https://www.google.com/search?q=eye+chart
- daniel_reetz 14y agoIt is known as the 1951 USAF Test Chart, and it is and was a standard: http://en.wikipedia.org/wiki/1951_USAF_resolution_test_chart http://en.wikipedia.org/wiki/1951_USAF_resolution_test_chart
- stevenrace 14y agoExactly what I was looking for, thanks. It seems the 'Milspec' status is: MIL-STD-150A, dated 06 January 1998, is hereby cancelled without replacement. With as many multi-spectral instruments we have floating about, I wonder what other shapes, compositions, or controlled temperature gradients might be in use under our noses.
- ramchip 14y agoIt's very common in microscopy, to check your resolution.
- thomasbk 14y agoIdea: remember the EURion constellation? http://en.wikipedia.org/wiki/EURion_constellation http://en.wikipedia.org/wiki/EURion_constellation It's a pattern of circles that's printed on money, and when printers detect it in a file they will refuse to print that file. I wonder what would happen if we similarly embedded this pattern in landscapes. Would it prevent printing aereal photo's?
- wtracy 14y agoDoes anyone know of any of these charts at locations accessible to the public? They appear interesting to look at.