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Computerized cephalometric analysis currently requires manual identification of landmark locations. This process is time-consuming and limited in accuracy. The purpose of this study was to develop and test a novel method for automatic computer identification of cephalometric landmarks. Spatial spectroscopy (SS) is a computerized method that identifies image(More)
Representing object shape in two or three dimensions has typically involved the description of the object boundary. This paper proposes a means for characterizing object structure and shape that avoids the need to find an explicit boundary. Rather, it operates directly from the imageintensity distribution in the object and its background, using operators(More)
PURPOSE To assess the accuracy with which the Keratron keratoscope (Optikon 2000, Rome, Italy) measured astigmatic test surfaces by a profile reconstruction algorithm within a plane geometry model and to discriminate between error caused by the model and error caused by other factors. METHODS Height was reported by the Keratron for eight surfaces with(More)
PURPOSE To assess the accuracy with which the Keratron (Optikon 2000, Rome, Italy) measured rotationally symmetric, radially aspheric test surfaces according to an arc-step profile reconstruction algorithm and to discriminate between error caused by the algorithm and error from other sources. METHODS Height, local power, and axial power calculated from(More)
Volume rendering is the generation of images from discrete samples of volume data. The volume data is sampled in at least three dimensions and comes in three basic classes: the rectilinear mesh-for example, a stack of computed tomography scans; the curvilinear mesh-for example, computational fluid dynamic data sets of the flow of air over an airplane wing;(More)
The diagnostic process of orthodontics requires the analysis of a cephalometric radiograph. Image landmarks on this two-dimensional lateral projection image of the patient's head are manually identified and spatial relationships are evaluated. This method is very time consuming. A reliable method for automatic computer landmark identification does not(More)
We present an approach for controlling relaxation parameters in variable conductance diffusion. This approach incorporates a Bayesian classifier to perform a partial labeling of an image, followed by a diffusion step. Conductance values between pixels are controlled by statistical measurements made of the partial classification. Several iterations follow,(More)
Evaluation of ocular hyperemia has been an important assessment in research studies of effects of contact lenses, medications, and pollutants on the eye. Hyperemia has been difficult to quantitate objectively. The purpose of this study was to validate a computer based image analysis system to quantitate hyperemia automatically and objectively in pixelated(More)