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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)
A dynamic multi-leaf collimator (DMLC) can be used to track a moving target during radiotherapy. One of the major benefits for DMLC tumor tracking is that, in addition to the compensation for tumor translational motion, DMLC can also change the aperture shape to conform to a deforming tumor projection in the beam's eye view. This paper presents a method(More)
Respiratory gating and tumor tracking for dynamic multileaf collimator delivery require accurate and real-time localization of the lung tumor position during treatment. Deriving tumor position from external surrogates such as abdominal surface motion may have large uncertainties due to the intra- and interfraction variations of the correlation between the(More)
This paper is a 1-D analysis of the degradation caused by image sampling and interpolative reconstruction. The analysis includes the sample-scene phase as an explicit random parameter and provides a complete characterization of this image degradation as the sum of two terms: one term accounts for the mean effect of undersampling (aliasing) and nonideal(More)
Rectification or geometric correction of digital images refers to the 2-dimensional resampling of an image data array onto a new grid which is distorted with respect to the original grid. When an image on a mass storage device is very much larger than the available computer central memory, it is important to choose an algorithm for rectification which(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)