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A trip to the Mojave Desert

Cris

In early January 2012, the Center for Land Use Interpretation (CLUI) hosted a gathering of folks who take low altitude photographs using unconventional means. I drove the Westfalia down from Berkeley, an 1100-mile round trip, and had a great time camping along the way.

Resolution target #3 - Cuddeback Lake

Aerial camera resolution target – Cuddeback Lake

The group included rocketeers, kiters, balloonists, radio control aircraft fliers, pole balancers, throwers of balls, and more. The aerialists convened at CLUI’s Desert Research Station near Barstow in the Mojave Desert. We then ventured forth to the Cuddeback Dry Lake Bed to photograph a series of three resolution targets used in the testing of aircraft-based aerial surveillance platforms (think SR-71). Our photography platforms afforded a working height several orders of magnitude closer to the ground.

Resolution target #1 - Cuddeback Lake

Mathew Lippincott’s Tyvek delta above target #1

Over the course of an afternoon we visited three of these aerial photo resolution targets, each approximately the size of a basketball court. Surrounded by low fences, they were basically paved rectangles painted black with tar on which white three-bar patterns were painted in decreasing sizes. The targets were in a state of disrepair.

It was great fun being out under a big sky. I was lucky to find workable breezes at each of the target sites and took these photographs using a Sutton 16 and a Sutton 30.

As part of a discussion over on the KAP Discussion Page Bill Blake provided the following links, interesting all, regarding the resolution targets.

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A bit more on the US 1951AP target is here:

http://en.wikipedia.org/wiki/1951_USAF_resolution_test_chart

And a neat calculator here:

http://www.vision-doctor.co.uk/optical-calculations/usaf-1951-determination-resolution.html

An explanation of the element sizes here:

http://www.efg2.com/Lab/ImageProcessing/TestTargets

and Philip Thom has uploaded the 1959 edition of MIL STD 150a here:

http://www.philipp-thom.de/blog/wp-content/uploads/2013/03/MIL-STD-150A.pdf

All I wanted to know was how big the stripes are to get a simple photo scale…and it turns out these things are something of a monument to the heyday of the skunk works in the depths of the coldwar. Photogrammetry has moved on a lot since then but the optical performance of photography not so much.

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Whike Gerco provided this link to a blog post on Optical Calibration Targets.

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For my part here is a set of images from the afternoon session posted to Flickr:

 

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