A novel technique has been developed to verify the absolute accuracy and relative stability of a spaceborne microwave radiometer’s calibration using a statistical analysis of the measured Earth brightness temperatures (TBs). This procedure relies solely on the final, main beam-referenced TBs and so tests the complete end-to-end system calibration, including instrument temperature and non-linear...

Accurate measurement of the frequency-dependent shift of the self-absorbed radio core is required for multi-frequency analysis of VLBI data since absolute positional information is lost as a result of phase self-calibration. We use the cross-correlation technique of Croke & Gabuzda (2008) on the optically thin jet emission to align our VLBA images. Our results are consistent with those obtained...

Aims. We describe a 6–12 GHz analogue correlator that has been developed for use in radio interferometers. Methods. We use a lag-correlator technique to synthesis eight complex spectral channels. Two schemes were considered for sampling the cross-correlation function, using either real or complex correlations, and we developed prototypes for both of them. We opted for the “add and square” detec...

PURPOSE To determine the prevalence of calibration errors in Goldmann applanation tonometers at Farabi Eye Hospital. METHODS This cross-sectional study was performed on all tonometers in use at Farabi Eye Hospital. All Haag-Streit Goldmann applanation tonometers were checked according to the manufacturer's method by two independent observers and by a third observer in case of mismatched resul...

The GaoFen-4 (GF-4), launched at the end of December 2015, is China’s first high-resolution geostationary optical satellite. A panchromatic and multispectral sensor (PMS) is onboard the GF-4 satellite. Unfortunately, the GF-4 has no onboard calibration assembly, so on-orbit radiometric calibration is required. Like the charge-coupled device (CCD) onboard HuanJing-1 (HJ) or the wide field of vie...

Many real time ultrasound (US) guided therapies can benefit from management of motion-induced anatomical changes with respect to a previously acquired computerized anatomy model. Spatial calibration is a prerequisite to transforming US image information to the reference frame of the anatomy model. We present a new method for calibrating 3D US volumes using intramodality image registration, deri...

The paper reports a fully-automated, cross-modality sensor data registration scheme between video and magnetic tracker data. This registration scheme is intended for use in computerized imaging systems to model the appearance, structure, and dimension of human anatomy in three dimensions (3D) from endoscopic videos, particularly colonoscopic videos, for cancer research and clinical practices. T...

Ultrasonic cross-correlation flow meters using natural turbulences in a fluid must be calibrated. The reason is that the most frequent components in the fluid are determined by this method deviating from the average flow velocity. The calibration characteristic is nonlinear and depends on the flow velocity and profile, respectively. This disadvantage can be avoided by small artificially generat...

In this article we estimate default intensities within the continuous time Jarrow/Turnbull (1995) model from daily observations of German bank bond prices, based on the default-free term structure estimated from the Svensson (1994) model provided by the Deutsche Bundesbank. Cross-sectional and time-series estimations are performed. We show that pricing errors from the term structure estimation ...

Abstract. Many examples of calibration in climate science raise no alarms regarding model reliability. We examine one example and show that, in employing Classical Hypothesis-testing, it involves calibrating a base model against Many examples of calibration in climate science raise no alarms regarding model reliability. We examine one example and show that, in employing Classical Hypothesis-tes...