Robert A. Schowengerdt

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We have classified four different images, under various levels of JPEG compression, using the following classification algorithms: minimum-distance, maximum-likelihood, and neural network. The training site accuracy and percent difference from the original classification were tabulated for each image compression level, with maximum-likelihood showing the(More)
The two-pass (or multipass) image geometric transformation algorithm is ideally suited to real-time, parallel implementation, but is known to introduce frequency aliasing during rotation, over and above any aliasing which may result from the usual one-pass algorithm. We develop a unified framework and theory that precisely explains this added-aliasing for(More)
This paper investigates airborne helicopter video for estimating traffic parameters. Roll, pitch, and yaw of the helicopter make the video unstable, difficult to view, and the derived parameters less accurate. To correct this, a frame-by-frame video-registration technique using a feature tracker to automatically determine control-point correspondences is(More)
Techniques for incorporating airborne video into a multimedia GIS for traffic flow visualization are described. The base layer of the GIS consists of mosaiced aerial orthographic images of Tucson. Digitized non-roadway segments serve as a mask to emphasize roadways. A helicopter with a sophisticated on-board attitude measurement system was used to collect(More)