Unmanned small-format aerial photography from kites for acquiring large-scale, high-resolution, multiview-angle imagery

Abstract

Kite aerial photography (KAP) involves large kites for lifting cameras 50-150 m above the ground. Either soft (airfoil) or rigid (delta, rokkaku) kites may be utilized in wind ranging from 10 to 40 km/h. Various film, digital, or video imaging devices are employed in single- or dual-camera rigs for acquiring individual images, multiband photos, or stereopairs. Camera pan, tilt, and shutter are operated by radio control from the ground. Photographs may be obtained in visible and near-infrared portions of the spectrum using different film/filter combinations. Photographs can be taken in any position-vertical, low- and high-oblique, and in any orientation relative to the sun and ground object. Vertical digital KAP typically has pixel resolution of 5-10 cm, and about to 1 hectare ground area is depicted in a single scene. Kite aerial photography is highly portable and can be operated in almost any situation with an open flying field. A crew of two is sufficient normally, one to fly the kite, the other to operate radio controls and take pictures. Low cost makes this method feasible for routine operation by small organizations, and the method is convenient for frequent photography to document environmental changes. We have utilized kite aerial photography for diverse research and commercial applications including assessment of forests and wetlands, investigations of fluvial and glacial landforms, depiction of multiview-angle reflectance phenomena, and surveys of property and construction sites. KAP has proven valuable for bridging the scale and resolution gap between ground observations and conventional airphotos and satellite images.