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n2doc

(47,953 posts)
Sun Feb 17, 2013, 08:02 PM Feb 2013

There Are Giant Camera Resolution Test Charts Scattered Across the US



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:




more

http://www.petapixel.com/2013/02/15/there-are-giant-camera-resolution-test-charts-scattered-across-the-us/
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There Are Giant Camera Resolution Test Charts Scattered Across the US (Original Post) n2doc Feb 2013 OP
Alien landing instructions Angry Dragon Feb 2013 #1
Here's the second one in your post.. Princess Turandot Feb 2013 #2
USDA aerial maps from the 50s are fascinating historical documents Robb Feb 2013 #3
k & r surrealAmerican Feb 2013 #4
K&R Champion Jack Feb 2013 #5

Robb

(39,665 posts)
3. USDA aerial maps from the 50s are fascinating historical documents
Sun Feb 17, 2013, 08:58 PM
Feb 2013

...created, every one, from aerial photographs -- equally fascinating, those.

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