PetaPixel

There Are Giant Camera Resolution Test Charts Scattered Across the US

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When people test cameras and lenses for resolution, they commonly use special resolution test charts that are filled with black bars of varying lengths and thicknesses. They’re kind of like eye charts, except for cameras instead of eyeballs, and with lines instead of letters.

Well, did you know that in dozens of locations around the United States, there are gigantic resolution test charts on the ground?

The Center for Land Use Interpretation writes that the strange “land-based two-dimensional optical artifacts” are used for the development of aerial photography — cameras built into airplanes and drones.

The resolution charts were mostly used during the 50s and 60s, but some of them may still be used nowadays to calibrate “flying cameras.” They have dimensions of around 50-80 feet and are coated in heavy black and white paint. Here’s what one target looks like from the ground:

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The layout of the charts become much more apparent when they’re viewed from the air:

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Camera-equipped aerial vehicles can fly over the giant charts and use them to test, calibrate, and focus their cameras while traveling at various altitudes and speeds. Even satellites can utilize the charts. Here’s a chart as seen by the satellite used for Google Maps:

The location you see in the Google Map above is Edwards Air Force Base, which has the highest concentration of these calibration targets in one place. They’re found in the base’s “photo resolution range,” which features 15 of these targets splattered across 20 miles of Earth on the southeast side of the base. This allows a single plane to utilize multiple targets without having to loop back or change course.

Here are a couple of the other targets in the range, as seen through Google Maps’ Satellite View:

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The CLUI reports that there are currently an unknown number of these targets scattered across the country, usually inside restricted areas in military airstrips.

If you’re ever flying in a plane with your camera gear in tow and find yourself traveling over a military base, see if you can spot one of these charts to do some impromptu resolution tests on your camera and lens!

(via CLUI via BLDGBLOG via kottke.org)


P.S. The Curiosity rover on Mars has one of these charts built into its body.


Image credits: Photographs by The Center for Land Use Interpretation


 
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  • 3ric15

    Freaky…at least we know what they’re for, unlike those in North Korea or in the deserts of China.

  • Wilba

    Now we know what aliens use crop circles for…

  • Mark N

    I imagine those would be for cameras as well ;-)

  • http://www.facebook.com/burnin.biomass Burnin Biomass

    I knew there were a set of these at Wright-Patterson Air Force Museum. They are just south west of the main building (follow the old runway down). You can see them on Google earth

  • http://www.facebook.com/duke.shin1 Duke Shin

    As soon as the borders open up, I’m grabbing every Zorkii and Fed I can get my hands on.

  • Buzzerfly

    Go look for the huge array near Covington, LA.

  • Cezar

    haha exactly what i was thinking! There’s not enough Zorkis and Feds in the UK!

  • Peter Arbib

    Yes, for areal cameras, large format sheet or roll film. My Dad was an army photographer that photographed enemy places via a fly over mission.

  • Mike McRoberts

    Google Maps doesn’t use satellites. All of the Google Maps images are created using aircraft.

  • http://twitter.com/stuinzuri Stu Thompson

    That’s not true. For locations where they have aircraft data, that is used in the close ups. But otherwise it is satellite data.

  • http://www.facebook.com/people/Steve-Yuhas/550906392 Steve Yuhas

    These can’t be for testing drones and overhead cameras. It’s not possible – they were left by aliens to test their drone technology (or it’s DHS). Either way, I say we screw with their little charts and make their cameras useless (insert Dr. Evil laugh).

  • Peter A Blacksberg

    I believe the chart was developed at the Rochester Institute of Technology, The lines are turned 90 degrees to one another to allow readers to state which orientation the line groups are in. This is preferred to letters, which can be guessed.

  • Olga Peluso

    If you think Joseph`s story is impressive…, won weak-ago my doughter basically got $7348 working fourteen hours a week from there house and they’re neighbor’s mother-in-law`s neighbour has been doing this for five months and brought home over $7348 part-time from a mac. follow the tips from this website… jump15.comCHECK IT OUT

  • Daniel Bacellar

    Aliens left Nazca lines to this use.

  • dirk

    Anybody have lat/lons for these images?

  • Raffzahn

    They use whatever technology is available to their mind controled human drones. Stonhenge, Nazca, Edwards AFB, you name it.

  • Ranger 9

    The bars are turned at 90 degrees to allow testing for astigmatism (differing resolution on different axes.)