Freehand three-dimensional (3D) ultrasound is a technique for acquiring ultrasonic data of a 3D volume with application in radiotherapy and surgery planning. As the clinician sweeps the ultrasound probe over the anatomy, the trajectory of the probe is recorded using an attached position sensor. However, the position sensor tracks the position of the sensor, rather than the ultrasound B-scan. It...

OBJECTIVE Calibration errors in distortion-product otoacoustic emission (DPOAE) measurements because of standing waves cause unpredictable changes in stimulus and DPOAE response level. The purpose of this study was to assess the extent to which these errors affect DPOAE test performance. Standard calibration procedures use sound pressure level (SPL) to determine specified levels. Forward pressu...

This work summarizes the overall calibration strategy for WFPC2, covering the design of the observational programs as well as analysis of the results and their incorporation into the calibration pipeline. This strategy comprises routine long-term calibration monitoring programs, including darks, biases, flat fields, photometric and astrometric monitoring, as well as special calibration programs...

In time-of-flight range imagers, as the range resolution increases, a gating clock skew becomes a serious problem. This paper describes two skew calibration techniques implemented in column-parallel circuits for TOF range imagers. Skew calibration technique with optical response is simple but the long calibration time is required. To reduce the calibration time, self-calibration technique with ...

Overall system calibration is one limiting factor in direct georeferencing. Within this context the stability of system calibration over longer time periods and the influence of additional self-calibration is of special interest. The investigations presented are based on test material from a real flight test, where a calibration field was flown several times within a two month period using the ...

BACKGROUND The addition of a calibration curve with every run is both time-consuming and expensive for clinical mass spectrometry assays. We present alternative calibration strategies that eliminate the need for a calibration curve except as required by laboratory regulations. METHODS We measured serum nortriptyline concentrations prospectively in 68 patients on 16 days over a 2-month period ...

Some of the biggest challenges in gaze interaction are calibration and accuracy. Calibration problems often occur if the user shifts position during the interaction or if the initial calibration has been done poorly. Even when calibration works for most of the screen, problems may still occur near the edges of the screen, especially at the bottom of the screen. With some eye trackers, the calib...

ISO 9001 (ISO 1987) certification issues are bringing-out calibration anxieties. The rush to document calibration intervals for certification purposes is often driving-up costs. Both instrument manufactures and calibration services are benefiting financially from calibration anxiety brought on by “ISO systems requiring you to say what you do and do what you say to meet the ISO specifications”. ...

Probabilistic calibration is the task of producing reliable estimates of the conditional class probability P (class|observation) from the outputs of numerical classifiers. A recent comparative study [1] revealed that Isotonic Regression [2] and Platt Calibration [3] are most effective probabilistic calibration technique for a wide range of classifiers. This paper will demonstrate that these met...

In this study, colorimetric calibration of scanner has been done via perceptron neural network with three or four layers by back propagation algorithm for colored polyester fabrics. The results obtained for random training samples are not satisfactory but application of selective training samples for L*a*b* or RGB leads to good results, with better results obtained for the L*a*b* method. On the...