Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “calibration methods”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 919 records · Page 51
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Characterizing and Mitigating Intraday Variability: Reconstructing Source Structure in Accreting Black Holes with mm-VLBI

The extraordinary physical resolution afforded by the Event Horizon Telescope has opened a window onto the astrophysical phenomena unfolding on horizon scales in two known black holes, M87* and Sgr A*. However, with this leap in resolution has come a new set of practical complications. Sgr A* exhibits intraday variability that violates the assumptions underlying Earth aperture synthesis, limiting traditional image reconstruction methods to short timescales and data sets with very sparse (u, v) coverage. We present a new set of tools to detect and mitigate this variability. We develop a data-driven, model-agnostic procedure to detect and characterize the spatial structure of intraday variability. This method is calibrated against a large set of mock data sets, producing an empirical estimator of the spatial power spectrum of the brightness fluctuations. We present a novel Bayesian noise modeling algorithm that simultaneously reconstructs an average image and statistical measure of the fluctuations about it using a parameterized form for the excess variance in the complex visibilities not otherwise explained by the statistical errors. These methods are validated using a variety of simulated data, including general relativistic magnetohydrodynamic simulations appropriate for Sgr A* and M87*. We find that the reconstructed source structure and variability are robust to changes in the underlying image model. We apply these methods to the 2017 EHT observations of M87*, finding evidence for variability across the EHT observing campaign. The variability mitigation strategies presented are widely applicable to very long baseline interferometry observations of variable sources generally, for which they provide a data-informed averaging procedure and natural characterization of inter-epoch image consistency.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS2017

Evaluation of Methods for In-Situ Calibration of Field-Deployable Microphone Phased Arrays

Current field-deployable microphone phased arrays for aeroacoustic flight testing require the placement of hundreds of individual sensors over a large area. Depending on the duration of the test campaign, the microphones may be required to stay deployed at the testing site for weeks or even months. This presents a challenge in regards to tracking the response (i.e., sensitivity) of the individual sensors as a function of time in order to evaluate the health of the array. To address this challenge, two different methods for in-situ tracking of microphone responses are described. The first relies on the use of an aerial sound source attached as a payload on a hovering small Unmanned Aerial System (sUAS) vehicle. The second relies on the use of individually excited ground-based sound sources strategically placed throughout the array pattern. Testing of the two methods was performed in microphone array deployments conducted at Fort A.P. Hill in 2015 and at Edwards Air Force Base in 2016. The results indicate that the drift in individual sensor responses can be tracked reasonably well using both methods. Thus, in-situ response tracking methods are useful as a diagnostic tool for monitoring the health of a phased array during long duration deployments.

Humphreys, William M.↗
DOE OSTI2018

Results from the Atacama B-mode Search (ABS) experiment

We report the Atacama B-mode Search is an experiment designed to measure the cosmic microwave background polarization at large angular scales (0ℓ>4). It observes at 145 GHz from a site at 5,190 m elevation in northern Chile. The noise equivalent polarization temperature, or NEQ, is 41 μK√s. One of the unique features of ABS is its use of a rapidly rotating ambient-temperature half-wave plate (HWP) {as the first optical element}. {The HWP spins} at 2.55 Hz to modulate the incident polarized signal at frequencies above where instrument white noise dominates over atmospheric fluctuations and other sources of low-frequency noise. We report here on the analysis of data from a 2,400 deg 2 region of sky. We perform a blind analysis to reduce potential bias. After unblinding, we find agreement with the Planck TE and EE measurements on the same region of sky, {with a derived calibration factor of 00.89 ± 0.1}. We marginally detect polarized dust emission {(at 3.2 σ for EE and 2.2 σ for BB)} and give an upper limit on the tensor-to-scalar ratio of r<2.3 (95% confidence level) with the equivalent of 100 on-sky days of observation. Finally, we also present a new measurement of the polarization of Tau A and introduce new methods for calibration and data analysis associated with HWP-based observations.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2026

pyFLANK, a graph neural network based null distribution inference model for F ST outlier detection

Detecting genomic regions under selection is essential for understanding how populations adapt to different environments, yet it remains challenging due to the confounding effects of demographic history and linkage disequilibrium (LD). Fixation index (F ST ) is a widely used statistic to identify genomic regions under adaptation. However, identifying genes under selection by defining F ST outliers often remains challenging, owing to confounding effects of underlying demographic history. Traditional methods assume independence among loci and rely on simple demographic models, while newer models perform much better but are computationally expensive and not easily scalable. Here, we present pyFLANK, an open-source and automated Python implementation which detects F ST outliers using a null distribution inferred from quasi-independent loci. Our tool integrates three approaches to identify loci obeying a null distribution: graph neural network (GNN) inference, linkage disequilibrium (LD)-based inference, and user-defined input. Because pyFLANK uses GNN-based inference of quasi-independent loci, it yields a more accurate null model with less need for user parameter input. In simulation experiments, pyFLANK achieved lower false positive rates than current methods while maintaining comparable detection power, indicating that its refined null model better distinguishes true adaptive loci from background variation. The GNN-based model, in particular, detected additional loci associated with phenotypic variance that were not identified by existing methods. Assessments of simulation and real data from different species demonstrate that pyFLANK achieves lower false positive rates compared with other commonly used F ST outlier detectors, while maintaining comparable detection power and excellent computational performance, providing a robust and user-friendly tool for identifying loci under divergent selection. It extends existing F ST outlier frameworks by incorporating explicit LD-aware strategies for null model calibration. The method is intended as a practical and scalable complement to existing genome scan approaches.

FST↗
NASA NTRS1993

Calibrating Airplane Instrumentation To Measure Winds

Elaborate combination of techniques used to calibrate wind-measuring instrumentation aboard F104 airplane. Obtains wind profiles more rapidly. Airplane equipped with standard NACA research nose boom, including pressure probes and flow vanes yielding data on static and total pressures, angle of attack, and angle of sideslip. Has ring-laser-gyroscope inertial reference unit, giving linear and angular velocities, linear acceleration, and orientation of airplane. Body-mounted total-temperature sensor also used. Improved method of calibration devised to determine whether winds aloft at and shortly after time of measurement allow safe launch of Space Shuttle. Proves beneficial in other safety- or research-oriented applications in which wind velocities over range of altitudes must be determined in nearly real time.

Haering, Edward A., Jr.↗
DOE OSTI2026

Deep Learning enabled spectral energy conversion for in situ exposure measurements

A detector-specific deep learning (DL) approach is presented for spectra-to-exposure conversion using large-format sodium iodide (NaI(Tl)) detectors deployed for in situ environmental radiation measurements in emergency response scenarios. Accurate determination of exposure from NaI spectra is challenging due to poor energy resolution, partial energy absorption, and the strong sensitivity of traditionally deployed analytical conversion methods to calibrated source geometry and pre-deployment assumptions. Here, to address these limitations, a multi-layer perceptron model was trained on a hybrid in situ /Monte Carlo dataset constructed to span a broad range of photon energies, spatial extents, and realistic deployment variability, representative of general in situ emergency response conditions. The DL model was evaluated against commonly fielded analytical approaches under matched simulation conditions, including a single-factor method, a G-function method, and a modeled pressurized ion chamber (PIC) baseline. This study was intentionally computational in scope to enable controlled, like-for-like comparisons between conversion techniques while minimizing confounding real-world variability. Comparison to the modeled PIC provides contextual benchmarking and is not intended as a field inter-comparison with deployed instruments. Across the evaluated 20 keV to 3 MeV energy range, the DL approach consistently exhibited higher accuracy and reduced variance relative to the analytical methods against a deterministically calculated exposure. This may indicate improved robustness to spectral complexity without reliance on source-, geometric-, or spectral region-specific optimization. While results do not represent real-world validation, the presented work demonstrates that deep learning may effectively learn the nonlinear detector response-to-exposure relationship for asymmetric NaI(Tl) detectors and offers a promising pathway for improving in situ exposure estimation using spectroscopic systems already integrated into initial real-time emergency response operations.

61 RADIATION PROTECTION AND DOSIMETRY↗
DOE OSTI2026

Second Harmonic Generation Electric Field Triplet Interferometry for Absolute Phasing

We report second harmonic generation (SHG) electric field triplet interferometry performed using three mutually coherent ultrafast pulses in a common path with controllable relative phases, namely, the light fields of a sample signal (SI), a reference oscillator (RO), and a local oscillator (LO). The ROLO phase determined from the interference of the light fields produced by two quartz wafers is subtracted from the phase determined from the SIROLO interferogram to yield the signal phase, ϕ SI . The new method also calibrates the measured SHG intensity from a given sample internally by sending the fundamental light field reflected from the sample into one of the quartz wafers in the ROLO element. The approach avoids having to exchange the sample against a reference material with a known χ(2) value or known phase and accounts on-the-fly for situations where the reflected fundamental light field intensity changes with experimental conditions. The new method is successfully benchmarked against z-cut α-quartz, fused silica held at its point of zero charge, and hematite nanolayers in air, across three different interferometers. Furthermore, the approach should be applicable for other second-order nonlinear spectroscopies, such as vibrational or electronic sum-frequency generation.

Interfaces↗
NASA NTRS1983

Electron-photon coincidence technique for the absolute calibration of VUV detectors

A method is described whereby VUV photon detectors can be accurately calibrated. This method is illustrated by taking the 58.4-nm transition of He as an example. The technique consists of crossing a monoenergetic electron beam with a beam of He atoms. When inelastically scattered electrons which have excited the 2 1P state are detected in coincidence with the 58.4-nm photons emitted in the decay of the excited state, the interaction volume formed by the crossed beams constitutes a standard source of photons. By comparing the number of detected coincidences with the predicted number the calibration can be made. A total detector efficiency of 0.024 + or - 0.003 is obtained for a Galileo 4830 channeltron.

Mcadams, R.↗
NASA NTRS2012

Development of IR Contrast Data Analysis Application for Characterizing Delaminations in Graphite-Epoxy Structures

Objective: Develop infrared (IR) flash thermography application based on use of a calibration standard for inspecting graphite-epoxy laminated/honeycomb structures. Background: Graphite/Epoxy composites (laminated and honeycomb) are widely used on NASA programs. Composite materials are susceptible for impact damage that is not readily detected by visual inspection. IR inspection can provide required sensitivity to detect surface damage in composites during manufacturing and during service. IR contrast analysis can provide characterization of depth, size and gap thickness of impact damage. Benefits/Payoffs: The research provides an empirical method of calibrating the flash thermography response in nondestructive evaluation. A physical calibration standard with artificial flaws such as flat bottom holes with desired diameter and depth values in a desired material is used in calibration. The research devises several probability of detection (POD) analysis approaches to enable cost effective POD study to meet program requirements.

Havican, Marie↗
DOE OSTI2016

SU-F-T-175: Absorbed Dose Measurement Using Radiophotoluminescent Glass Dosimeter in Therapeutic Proton Beam

Purpose: To measure the absorbed dose to water Dw in therapeutic proton beam with radiophotoluminescent glass dosimeter (RGD), a methodology was proposed. In this methodology, the correction factor for the LET dependence of radiophotoluminescent (RPL) efficiency and the variation of mass stopping power ratio of water to RGD (SPRw, RGD) were adopted. The feasibility of proposed method was evaluated in this report. Methods: The calibration coefficient in terms of Dw for RGDs (GD-302M, Asahi Techno Glass) was obtained using 60Co beam. The SPRw, RGD was calculated by Monte Carlo simulation toolkit Geant4. The LET dependence of RPL efficiency was investigated experimentally by using a 70 MeV proton beam at National Institute of Radiological Sciences. For clinical usage, the residual range Rres was used as a quality index to determine the correction factor for RPL efficiency. The proposed method was evaluated by measuring Dw at difference depth in the 200 MeV proton beam. Results: For both modulated and non-modulated proton beam, the SPRw, RGD increases more than 3 % where Rres are less than 1 cm. RPL efficiency decreases with increasing LET and it reaches 0.6 at LET of 10 keV µm{sup −1}. Dw measured by RGD (Dw, RGD) shows good agreement with that measured by ionization chamber (Dw, IC) and the relative difference between Dw, RGD and Dw, IC are within 3 % where Rres is larger than 1 cm. Conclusion: In this work, a methodology for using RGD in proton dosimetry was proposed and the SPRw, RGD and the LET dependence of RPL efficiency in therapeutic proton beam was investigated. The results revealed that the proposed method is useful for RGD in the dosimetry of proton beams.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2016

SU-F-T-262: Commissioning Varian Portal Dosimetry for EPID-Based Patient Specific QA in a Non-Aria Environment

Purpose: Development of an in-house program facilitates a workflow that allows Electronic Portal Imaging Device (EPID) patient specific quality assurance (QA) measurements to be acquired and analyzed in the Portal Dosimetry Application (Varian Medical Systems, Palo Alto, CA) using a non-Aria Record and Verify (R&V) system (MOSAIQ, Elekta, Crawley, UK) to deliver beams in standard clinical treatment mode. Methods: Initial calibration of an in-house software tool includes characterization of EPID dosimetry parameters by importing DICOM images of varying delivered MUs to determine linear mapping factors in order to convert image pixel values to Varian-defined Calibrated Units (CU). Using this information, the Portal Dose Image Prediction (PDIP) algorithm was commissioned by converting images of various field sizes to output factors using the Eclipse Scripting Application Programming Interface (ESAPI) and converting a delivered configuration fluence to absolute dose units. To verify the algorithm configuration, an integrated image was acquired, exported directly from the R&V client, automatically converted to a compatible, calibrated dosimetric image, and compared to a PDIP calculated image using Varian’s Portal Dosimetry Application. Results: For two C-Series and one TrueBeam Varian linear accelerators, gamma comparisons (global 3% / 3mm) of PDIP algorithm predicted dosimetric images and images converted via the inhouse system demonstrated agreement for ≥99% of all pixels, exceeding vendor-recommended commissioning guidelines. Conclusion: Combinations of a programmatic image conversion tool and ESAPI allow for an efficient and accurate method of patient IMRT QA incorporating a 3rd party R&V system.

60 APPLIED LIFE SCIENCES↗
NASA NTRS1993

AVIRIS calibration using the cloud-shadow method

More than 90 percent of the signal at an ocean-viewing, satellite sensor is due to the atmosphere, so a 5 percent sensor-calibration error viewing a target that contributes but 10 percent of the signal received at the sensor may result in a target-reflectance error of more than 50 percent. Since prelaunch calibration accuracies of 5 percent are typical of space-sensor requirements, recalibration of the sensor using ground-base methods is required for low-signal target. Known target reflectance or water-leaving radiance spectra and atmospheric correction parameters are required. In this article we describe an atmospheric-correction method that uses cloud shadowed pixels in combination with pixels in a neighborhood region of similar optical properties to remove atmospheric effects from ocean scenes. These neighboring pixels can then be used as known reflectance targets for validation of the sensor calibration and atmospheric correction. The method uses the difference between water-leaving radiance values for these two regions. This allows nearly identical optical contributions to the two signals (e.g., path radiance and Fresnel-reflected skylight) to be removed, leaving mostly solar photons backscattered from beneath the sea to dominate the residual signal. Normalization by incident solar irradiance reaching the sea surface provides the remote-sensing reflectance of the ocean at the location of the neighbor region.

Carder, K. L.↗
DOE OSTI2012

Systematic measurements of whole-body imaging dose distributions in image-guided radiation therapy

Purpose: The full benefit of the increased precision of contemporary treatment techniques can only be exploited if the accuracy of the patient positioning is guaranteed. Therefore, more and more imaging modalities are used in the process of the patient setup in clinical routine of radiation therapy. The improved accuracy in patient positioning, however, results in additional dose contributions to the integral patient dose. To quantify this, absorbed dose measurements from typical imaging procedures involved in an image-guided radiation therapy treatment were measured in an anthropomorphic phantom for a complete course of treatment. The experimental setup, including the measurement positions in the phantom, was exactly the same as in a preceding study of radiotherapy stray dose measurements. This allows a direct combination of imaging dose distributions with the therapy dose distribution. Methods: Individually calibrated thermoluminescent dosimeters were used to measure absorbed dose in an anthropomorphic phantom at 184 locations. The dose distributions from imaging devices used with treatment machines from the manufacturers Accuray, Elekta, Siemens, and Varian and from computed tomography scanners from GE Healthcare were determined and the resulting effective dose was calculated. The list of investigated imaging techniques consisted of cone beam computed tomography (kilo- and megavoltage), megavoltage fan beam computed tomography, kilo- and megavoltage planar imaging, planning computed tomography with and without gating methods and planar scout views. Results: A conventional 3D planning CT resulted in an effective dose additional to the treatment stray dose of less than 1 mSv outside of the treated volume, whereas a 4D planning CT resulted in a 10 times larger dose. For a daily setup of the patient with two planar kilovoltage images or with a fan beam CT at the TomoTherapy unit, an additional effective dose outside of the treated volume of less than 0.4 mSv and 1.4 mSv was measured, respectively. Using kilovoltage or megavoltage radiation to obtain cone beam computed tomography scans led to an additional dose of 8-46 mSv. For treatment verification images performed once per week using double exposure technique, an additional effective dose of up to 18 mSv was measured. Conclusions: Daily setup imaging using kilovoltage planar images or TomoTherapy megavoltage fan beam CT imaging can be used as a standard procedure in clinical routine. Daily kilovoltage and megavoltage cone beam computed tomography setup imaging should be applied on an individual or indication based protocol. Depending on the imaging scheme applied, image-guided radiation therapy can be administered without increasing the dose outside of the treated volume compared to therapies without image guidance.

60 APPLIED LIFE SCIENCES↗
NASA NTRS2012

Calibration of PCB-132 Sensors in a Shock Tube

While PCB-132 sensors have proven useful for measuring second-mode instability waves in many hypersonic wind tunnels, they are currently limited by their calibration. Until now, the factory calibration has been all that was available, which is a single-point calibration at an amplitude three orders of magnitude higher than a second-mode wave. In addition, little information has been available about the frequency response or spatial resolution of the sensors, which is important for measuring high-frequency instability waves. These shortcomings make it difficult to compare measurements at different conditions and between different sensors. If accurate quantitative measurements could be performed, comparisons of the growth and breakdown of instability waves could be made in different facilities, possibly leading to a method of predicting the amplitude at which the waves break down into turbulence, improving transition prediction. A method for calibrating the sensors is proposed using a newly-built shock tube at Purdue University. This shock tube, essentially a half-scale version of the 6-Inch shock tube at the Graduate Aerospace Laboratories at Caltech, has been designed to attain a moderate vacuum in the driven section. Low driven pressures should allow the creation of very weak, yet still relatively thin shock waves. It is expected that static pressure rises within the range of second-mode amplitudes should be possible. The shock tube has been designed to create clean, planar shock waves with a laminar boundary layer to allow for accurate calibrations. Stronger shock waves can be used to identify the frequency response of the sensors out to hundreds of kilohertz.

Berridge, Dennis C.↗
NASA NTRS1985

Energy calibration of the fly's eye detector

The methods used to calibrate the Fly's eye detector to evaluate the energy of EAS are discussed. The energy of extensive air showers (EAS) as seen by the Fly's Eye detector are obtained from track length integrals of observed shower development curves. The energy of the parent cosmic ray primary is estimated by applying corrections to account for undetected energy in the muon, neutrino and hadronic channels. Absolute values for E depend upon the measurement of shower sizes N sub e(x). The following items are necessary to convert apparent optical brightness into intrinsical optical brightness: (1) an assessment of those factors responsible for light production by the relativistic electrons in an EAS and the transmission of light thru the atmosphere, (2) calibration of the optical detection system, and (3) a knowledge of the trajectory of the shower.

Baltrusaitis, R. M.↗
NASA NTRS2020

Use of an Internal Mercury-Argon Lamp for the Calibration of Raman Frequency in Large Raman Images of Astromaterials

Raman imaging is an emerging tool for the analysis of meteorites, as it is capable of describing mineralogy, carbon composition/speciation, and crystal orientation all within a petrographic context. Adequately examining the heterogeneous composition of a meteorite, while maintaining low laser powers needed to prevent damage to meteorite mineralogy and organics, often requires the collection of large Raman images with long collection times on the timescale of days. However, the frequency calibration of the Raman instrument/spectrometer drifts on long timescales resulting in low frequency precision for the Raman spectra comprising a large Raman image. This decrease in frequency precision can compromise the analysis of geological markers that can provide important information on a meteorite sample. We examine, in detail, the change in bandwidth and frequency of the Raman bands and Hg-Ar emission lines in our Raman images as a function of time and laboratory temperature. To overcome the drift in calibration, we utilize a commercial WITec Raman instrument with an internal Hg-Ar calibration lamp to individually calibrate each spectrum in the Raman image. Our instrument, known as “Ratatoskr”, uses a beam splitter in place of the customary mirror to facilitate collection of Hg-Ar calibration lines concurrent with Raman spectra. We show that using the internal calibration we can improve the frequency precision for the spectra in our Raman images from ~±0.15 cm(exp -1) to ~±0.05 cm(exp -1) for Raman spectra collected over multiple days. This is important as it improves measurements of mineral chemistry, latent strain, and other features that are dependent upon accurate peak position determination. We also examine the spectral signal-to-noise ratio needed to minimize the frequency error when fitting bands to Gaussian/Lorentzian profiles. We then use our results to suggest a general method for calibrating the frequency of Raman spectra in large Raman images.

Jakubek, Ryan S.↗
DOE OSTI2019

A multi-scale calibration approach for process-oriented aggregated building energy demand models

Long-term energy planning relies largely on projections of future energy demand and hourly load profiles. Aggregate building models are increasingly being utilized to characterize the sensitivity of current and future building stocks to changes in climate, population, and building technology on city-to-regional-to-national scales. Due to challenges in the availability of data, those analyses have been limited to projection of energy demand at a single scale, usually state or country, while long-term planning power system models and production cost models might operate at different spatial scales such as energy regions which are focused on ensuring adequate generation infrastructure. In this work, we propose and evaluate a novel method to calibrate an aggregate building energy demand model (PNNL’s BEND model) against the best available data at the spatial scale of balancing authorities. This approach extends previous work on aggregated building energy demand by facilitating analysis of building energy demand across scales, in particular policy and operational decision-making scales. We show that the bias-corrected model estimates building electric loads reasonably well compared with estimates from a statistical model, but has the additional feature of flexibility across spatial scales. While the calibration approach is presently U.S.-centric and associated with U.S. energy regions, it can be extrapolated to other worldwide regions with similar scale challenges between policy and operational implementation decision making. We discuss the significant challenges involved in formulating and calibrating a complex physical model based on simulations of roughly 100,000 individual buildings against available aggregate regional electric load data and highlight areas for potential future work and improved data collection.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2015

A method for evaluating image quality of monochrome and color displays based on luminance by use of a commercially available color digital camera

Purpose: The aim of this study is to propose a method for the quantitative evaluation of image quality of both monochrome and color liquid-crystal displays (LCDs) using a commercially available color digital camera. Methods: The intensities of the unprocessed red (R), green (G), and blue (B) signals of a camera vary depending on the spectral sensitivity of the image sensor used in the camera. For consistent evaluation of image quality for both monochrome and color LCDs, the unprocessed RGB signals of the camera were converted into gray scale signals that corresponded to the luminance of the LCD. Gray scale signals for the monochrome LCD were evaluated by using only the green channel signals of the camera. For the color LCD, the RGB signals of the camera were converted into gray scale signals by employing weighting factors (WFs) for each RGB channel. A line image displayed on the color LCD was simulated on the monochrome LCD by using a software application for subpixel driving in order to verify the WF-based conversion method. Furthermore, the results obtained by different types of commercially available color cameras and a photometric camera were compared to examine the consistency of the authors’ method. Finally, image quality for both the monochrome and color LCDs was assessed by measuring modulation transfer functions (MTFs) and Wiener spectra (WS). Results: The authors’ results demonstrated that the proposed method for calibrating the spectral sensitivity of the camera resulted in a consistent and reliable evaluation of the luminance of monochrome and color LCDs. The MTFs and WS showed different characteristics for the two LCD types owing to difference in the subpixel structure. The MTF in the vertical direction of the color LCD was superior to that of the monochrome LCD, although the WS in the vertical direction of the color LCD was inferior to that of the monochrome LCD as a result of luminance fluctuations in RGB subpixels. Conclusions: The authors’ method based on the use of a commercially available color camera is useful to evaluate and understand the display performances of both monochrome and color LCDs in radiology departments.

60 APPLIED LIFE SCIENCES↗