Click here to enter the gallery
Consider it a barcode for bombers--an eye test for spy planes. Across empty stretches of the United States, an odd Cold War artifact persists. It is a series of asphalt rectangles coated in patterns of black and white paint. Based on the 1951 U.S. Air Force resolution test chart, the barcode-like patterns were used to test the ability and resolution of film cameras carried by airplanes.
Google Earth images of these camera test patterns have been collected in the winter 2013 newsletter of the Center for Land Use Interpretation.
Known as tri-bar photo targets and largely concentrated in the Mojave desert, they were used for half of a century to test the reliability of American surveillance equipment. This began with the U-2 and SR-71 spyplanes of the Cold War and continued more recently, with satellites and camera-equipped drones. According to the CLUI:
The pattern was adopted as a uniform way for the Air Force to test cameras in 1959, and has been updated several times. In 1998, after almost 50 years in use, a military code manual deemed the pattern an outdated standard for new cameras parts and insisted that it only be used as a way to test replacement camera equipment. In 2006, after 57 years as the standard for Air Force cameras, the test pattern was retired; non-film cameras had become more common, and the tri-bar didn't adapt well to digital photography.
I think a lot of solar paneled roofs look like bar codes too ha.
So how are these "mysterious"? Cool it with the sensationalist headlines, the traffic they bring you will be smaller than the traffic from long-time readers who leave you.
I thought these were used for satilite optical correction.
Well, if someone had no clue as to what these were or of their use, then they would in fact be mysteries to that person. You could almost say they would be "mysterious" then, couldn't you? Mysterious doesn't have to denote otherwordly or criminal or... well, anything but a mystery to the wonderer.
Post war technology was so cool, then along came the digital revolution. It was like the difference between Newtonian physics and relativity or algebra and calculus.
Martians also used them to calibrate their big telescopes.
1959 to 2006 is 47 years not 57. I know. I was born in 1959. It is now 2013 and I am 54 years old. Not difficult math. Just simple subtraction that anyone with a good abacus could do. Of course if you'd like to you can use a calculator app if you need to.