Absorbed dose to water in a cobalt-60 gamma-ray beam has been determined using a thick-walled graphite ionization chamber. The chamber was calibrated in a graphite phantom against a graphite calorimeter, and the graphite calibration factor was converted to a water calibration factor using published energy absorption coefficient ratios and a measured replacement factor. Comparisons between the g...

Autonomous calibration techniques are applied to the calibration of two sensors of a planar robot: a platen sensor and a coordination sensor. The redundant angle measurements of the platen sensor are used to identify its parameters, improving its output accuracy by better than a factor of two. Redundant position measurements using both sensors are also used in an attempt to further improve the ...

INTRODUCTION Angular encoder accuracy is often the key limiting factor in rotational metrology systems. Inconsistent spacing of the graduations and spindle error motion are major sources of encoder error. Through calibration, the repeatable components of encoder error can be eliminated. Calibration systems have been developed to measure the error map at 128 angular intervals, achieving 0.01" (a...

A speaker verification evaluation is presented on the Multisession Audio Research Project (MARP) corpus, for which speakers were recorded at regular intervals, in consistent conditions, over a period of three years. It is observed that the performance of an i-vector system with probabilistic linear discriminant analysis (PLDA) modelling decreases progressively, in terms of both discrimination a...

Intraocular pressure (IOP) is the only known modifiable risk factor for glaucoma. Besides being a cornerstone in glaucoma management, accurate measurement of IOP forms an important component of routine ophthalmic evaluation. Despite the innovation of various newer tonometers, Goldmann applanation tonometer is still considered the Gold standard for IOP measurement. However, there are several rep...

This paper describes a new approach to neural network implementation of photometric stereo for a rotational object with non-uniform reflectance factor. Three input images are acquired under different conditions of illumination. One illumination direction is chosen to be aligned with the viewing direction. We require no separate calibration object to estimate the associated reflectance maps. Ins...

This paper presents the latest design and implementation of the Magnetic, Angular Rate, and Gravity (MARC) sensor module. The MARG sensor module is designed for measuring 3-DOF orientations in real time without singularities. Each MARG sensor contains orthogonally mounted triads of micromachined rate sensors, accelerometers, and magnetometers for a total of nine sensor components. With an integ...

This paper deals with the definition of the input fluxes used for the calibration of the IUE Final Archive. The method adopted consists on the determination of the shape of the detector’s sensitivity curves using IUE low resolution observations with model fluxes of the DA white dwarf G191–B2B. A scale factor was then determined so that the IUE observations of some bright OAO–2 standards match t...