Kite Aerial Photography

A (Semi-) Serious Need

We got into kite aerial photography out of necessity. My company's main business is building simulator systems of the type used for flight simulation, vehicle simulation, entertainment, and virtual reality. We obtained a contract from the U.S. Army Topographic Engineering Center to prepare a library of texture patterns for simulators. Texture patterns are images used in simulators to provide the details on the surfaces of objects. The patterns "tile seamlessly" so that a large surface can be covered by repeating small patterns.

 There are several ways to make texture patterns. One way is make them up artisticly with the aid of various kinds of computer software. There are quite a few programs on the market that support the artistic creation of patterns. We discovered early-on that while artisticly made patterns are effective for graphics arts applications, they rarely look realistic enough to be used in simulators. Instead, for simulators it is better to derive patterns from photographs of the real subject matter. The photographic source materials are processed, using custom software we created, to produce texture patterns with accurate colors that also tile seamlessly. The background for this page is an artistic (not photographic) image made to tile seamlessly.

 Simulator builders need texture patterns with resolutions to match their applications. If a simulator is for training air combat, for example, the patterns on the ground need to cover large areas with relatively low resoulution. Higher and higher resolutions are needed for armored vehicles, driver training, and virtual reality systems. Getting low to medium resolution source material is challenging, but not impossible. There are lots of stock aerial photographs available; the job is to locate low-altitude color ones of the right subjects. Getting high resolution material is less difficult either, because one can simply go out and take pictures of the ground. However, medium resolution material poses a problem, and that is where kite aerial photography comes in.

 Much of the source material we need should be acquired from altitudes between 50 and 200 feet, with the camera pointed straight down. Kite aerial photography is one of the few methods for obtaining photographs that meet this requirement. When the idea of using kites struck, we knew nothing about the equipment of methods needed to carry out the idea.


Help from the Internet

A search on the Internet turned up Charles Benton's Kite Aerial Photography Home Page. By a fortunate coincidence, he had posted his page only a few weeks before we found it in our web search. He recommended we contact Brooks Leffler, the editor of the kite aerial photography magazine, the aerial eye.

 Brooks provided valuable advice that really got us started. We ended up getting Brooks to build us a complete KAP rig suitable to our requirements. Brooks' design and craftsmanship are nothing short of first rate. In a couple of months we've given the rig a lot of flight testing. The results have exceeded our expectations.

 The rig includes a Sutton Flowform 16 stickless kite with a long nylon fabric tail and the camera platform. The camera platform uses a Yashica T4 camera and two Futaba servoes. One servo controls pitch and the other actuates the shutter. Note that since we are mainly interested in straight down, there is no need for an azimuth servo. We asked for an elevation control on the grounds that since we would have the kite aloft anyway, it would be irrestable to want to take some more conventional scenic pictures. The Futaba radio control unit is a popular unit used for radio controlled model airplanes and the like. The framework for the camera platform was custom crafted of aluminum, with some nylon fittings.

The whole rig packs up compactly for travel.

Brooks Leffler's construction is neat and functional.

 The camera platform is carried from the kite line with a cross-type Picavet suspension. This works both to keep the platform level and to resist rotation. It is too much to ask of any suspension to keep everything stable in gusty winds. However we lose fewer frames to blur that I had supposed. Perhaps fifteen percent are spoiled due to blur. It may be that the winds in northern California, were we have been flying, are characteristically less gusty than elsewhere.


Light winds, heavy cameras

The kite requires about 8 mph of wind to lift the rig reliably. One ongoing project is find a kite that would lower the threshold to the 4-5 mph range to increase the flying envelope. I've obtained a large Delta Conyne but have not had circumstances to experiment with it. Most of the time the winds around here are too strong! (Not so elsewhere, like in Florida, where I couldn't get any pictures on a recent trip.)

 It is a great puzzle to me as to why people fly heavy single lens reflex (SLR) cameras. The advantage of an SLR camera is that by viewing through the taking lens, the photographer gets to see the exact image being captured. But the kite aerial photographer cannot enjoy this advantage, being on the wrong end of the string for that. SLR cameras are generally well-crafted, so maybe people are just after the overall quality, but I'm skeptical that with the lens focused at infinity and pictures taken in bright sun, that extra quality would really be noticed in the final product.

 Don't get me wrong. For applications other than kite photography, I'm an enthusiastic supporter of the heavy iron school of photography. I've got a camera that I can barely carry.
 
 

Kite flying: $165/hr.

An unexpected problem with kite photography is simply getting permission to fly the kite. Private landowners generally do not mind kite photography, but one does have to seek permission if it's necessary to go onto a private access road. Public spaces like parks are a bigger problem. It turns out that most parks in our area have either total prohibitions on kite flying, or severe restrictions. For example, flying is prohibited anywhere that the kite might come down in a wetland. Sometimes the prohibitions seem reasonable, other times not. In any case, getting the necessary exemption to the rules is often quite a bureaucratic exercise. Unlike private property, the public "landowner" is not often located on the land in question.

 The East Bay Regional Park District runs parks near San Francisco Bay. Duly noting the "commercial purposes" of our kite photography, has offered a permit for only $165 per hour. No concerns were expressed whatsoever about the safety of the enterprise, so long as we carry $2,000,000 in liability insurance (which actually we do, a business necessity). This is all very silly and very tedious.

 On the other hand, at Shoreline Park in Mountain View I explained what we wanted to do to the Chief Ranger, who immediately said "Of course, that makes sense." and gave me a permission note. Occasionally, one does find someone who absolutely refuses to give up their common sense.


Gallery

Pillar Point Harbor on California Highway 1, road to the boat launching area.

The harbor beach; blue water is revealed to be green when viewed vertically.

Housing invades farmland on the east side of San Francisco Bay.


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copyright 1995, Roy Latham, rlatham@cgsd.com