scholarly journals Effectiveness of Automatic Correction of Systematic Effects in Measuring Chains

2019 ◽  
Vol 19 (4) ◽  
pp. 132-143
Author(s):  
Mykhaylo Dorozhovets
Keyword(s):  
Correction Method ◽  
Switching Systems ◽  
Automatic Correction ◽  
Drift Correction ◽  
Linear Drift ◽  
Uncertainty Of Measurements ◽  
Measurement Function ◽  
Systematic Effects ◽  
Main Factors ◽  
Multiplicative Effects

Abstract The uncertainty of measurements associated with the following correction methods: advanced correction of additive linear drift, correction of additive and multiplicative effects, as well as joint correction of a linear drift and systematic additive and multiplicative effects is analyzed in the present article. For each correction method sensitivity coefficients and amplitude responses according to which noise and internal and external interferences influence the corrected measurement result have been determined. Besides uncertainty of reference quantities, the main factors which limit the efficiency of correction are: non-linearity of measurement function including non-linearity of ADC, no idealities of the switching systems and external and internal noises and periodic interferences. The efficiency of correction of systematic additive and multiplicative effects was studied for the multifunction 16 bit PCI DAQ of family NI 6250.

Development of a Drift-Correction Procedure for a Photoelectric Spectrometer

1978 ◽  
Vol 32 (1) ◽  
pp. 46-53 ◽  
Author(s):  
Gilbert B. Chapman ◽  
William A. Gordon
Keyword(s):  
Optical Path ◽  
Automatic Correction ◽  
Sample Analysis ◽  
Electronic Components ◽  
Drift Correction ◽  
Direct Reading ◽  
Coefficients Of Variation ◽  
Lamp Current ◽  
Analytical Calibration ◽  
Correction System

This procedure provides automatic correction for drifts in the radiometric sensitivity of each detector channel in a direct-reading emission spectrometer. Such drifts are customarily controlled by the regular analyses of standards, which provide corrections for changes in the excitational, optical, and electronic components of the instrument. This standardization procedure, however, corrects for the optical and electronic drifts, thus minimizing the time, effort, and cost of regularly processing standards. This method of radiometric drift correction uses a 1000-W tungsten-halogen reference lamp to illuminate each detector through the same optical path as that traversed during sample analysis. The responses of the detector channels to this reference light are regularly compared with channel responses to the same light intensity at the time of analytical calibration in order to determine and correct for drift. The coefficients of variation of these drift corrections average less than 1%. Except for placing the lamp in position, the procedure is fully automated and compensates for changes in spectral intensity due to variations in lamp current. A discussion of the implementation of this drift-correction system is included.

High-precision image-drift-correction method for EM images with a low signal-to-noise ratio

Microscopy ◽  
2014 ◽  
Vol 63 (4) ◽  
pp. 301-312 ◽  
Author(s):  
Shigeto Isakozawa ◽  
Sachihiko Tomonaga ◽  
Takahito Hashimoto ◽  
Norio Baba
Keyword(s):  
High Precision ◽  
Signal To Noise Ratio ◽  
Correction Method ◽  
Signal To Noise ◽  
Drift Correction ◽  
Noise Ratio

scholarly journals NOAA-AVHRR Orbital Drift Correction: Validating Methods Using MSG-SEVIRI Data as a Benchmark Dataset

2021 ◽  
Vol 13 (5) ◽  
pp. 925
Author(s):  
Yves Julien ◽  
José A. Sobrino
Keyword(s):  
Time Series ◽  
Standard Deviation ◽  
Land Surface ◽  
Correction Method ◽  
Drift Correction ◽  
Noaa Avhrr ◽  
Coarse Spatial Resolution ◽  
Orbital Drift ◽  
Better Than

National Oceanic and Atmospheric Administration–Advanced Very High Resolution Radiometer (NOAA-AVHRR) data provides the possibility to build the longest Land Surface Temperature (LST) dataset to date, starting in 1981 up to the present. However, due to the orbital drift of the NOAA platforms, no LST dataset is available before 2000 and the arrival of newer platforms. Although numerous methods have been developed to correct this orbital drift effect on the LST, a lack of validation has prevented their application. This is the gap we bridge here by using the 15 min temporal resolution of Meteosat Second Generation–Spinning Enhanced Visible and Infra-Red Imager (MSG-SEVIRI) data to simulate drifted and reference LST time series. We then use these time series to validate an orbital drift correction method based on solar zenith angle (SZA) anomalies that we presented in a previous work (C1), as well as two variations of this approach (C0 and C2). Our results show that the C0 method performs better than the two others, although its overall bias absolute value ranges up to 1 K, while standard deviation values remain around 3 K. This is verified for most land covers, for all NOAA platforms, and these statistics remain mostly stable with noise on SZA time series (from 0° to ±10°). With this study, we show that orbital drift correction methods can be thoroughly validated and that such validation should aim toward bias absolute values below 0.1 K and standard deviation values around 1.4 K at coarse spatial resolution. To validate other orbital drift correction approaches, the drifted and reference time series used in this work are freely available for download from the first author’s webpage. This will be the first step toward the building of an orbital-drift-corrected long-term LST dataset.

scholarly journals Van der Meer scan luminosity measurement and beam–beam correction

2021 ◽  
Vol 81 (1) ◽  
Author(s):  
Vladislav Balagura
Keyword(s):  
Electromagnetic Interaction ◽  
Hadron Collider ◽  
Correction Method ◽  
Hadron Colliders ◽  
Proton Proton ◽  
Main Method ◽  
Main Factors ◽  
Linear Force ◽  
Beam Parameters ◽  
Limited Accuracy

AbstractThe main method for calibrating the luminosity at Large Hadron Collider (LHC) is van der Meer scan where the beams are swept transversely across each other. This beautiful method was invented in 1968. Despite the honourable age, it remains the preferable tool at hadron colliders. It delivers the lowest calibration systematics, which still often dominates the overall luminosity uncertainty at LHC experiments. Various details of the method are discussed in the paper. One of the main factors limiting proton–proton van der Meer scan accuracy is the beam–beam electromagnetic interaction. It modifies the shapes of the colliding bunches and biases the measured luminosity. In the first years of operation, four main LHC experiments did not attempt to correct the bias because of its complexity. In 2012 a correction method was proposed and then subsequently used by all experiments. It was based, however, on a simplified linear approximation of the beam–beam force and, therefore, had limited accuracy. In this paper, a new simulation is presented, which takes into account the exact non-linear force. Depending on the beam parameters, the results of the new and old methods differ by $$\sim 1\%$$ ∼ 1 % . This needs to be propagated to all LHC cross-section measurements after 2012. The new simulation is going to be used at LHC in future luminosity calibrations.

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