Improvements in the design of thermal-infrared radiation thermometers and sensors.

A new design for thermal-infrared radiation thermometer and sensors is described. Critical optical elements, such as the field stop, Lyot stop, collimating lens, and detector, are placed inside a thermally stabilized assembly that is controlled using thermo-electric coolers and thermistors. The assembled radiation thermometer is calibrated using both variable-temperature fluid-bath and heat-pipe blackbodies from -45 °C to 75 °C and the use of a modified-Planck function and these blackbodies.

Calibration of night vision goggles: an SI-units-based gain measurement technique.

A gain measurement technique for the calibration of night vision goggles (NVG) is proposed and evaluated. This technique is based on the radiance measurements at the input and output of the NVG. In contrast to the old definition, which uses a non-International System of Units (SI) traceable luminance, the "equivalent luminance unit," the suggested technique utilizes the radiance quantities that are traceable to the SI units through National Institute of Standards and Technology (NIST) standards.

Infrared spectral responsivity scale realization and validations.

An InSb working standard radiometer, first calibrated at the National Institute of Standards and Technology (NIST) in 1999 against a cryogenic bolometer, was recently calibrated against a newly developed low-noise-equivalent-power pyroelectric transfer standard detector. The pyroelectric transfer standard, which can operate at the output of a monochromator, holds the newly realized NIST spectral power responsivity scale between 1.7 and 14 μm with an uncertainty of 1% (k=2).

Standardization of Broadband UV Measurements for 365 nm LED Sources.

Broadband UV measurements are evaluated when UV-A irradiance meters measure optical radiation from 365 nm UV sources. The CIE standardized rectangular-shape UV-A function can be realized only with large spectral mismatch errors. The spectral power-distribution of the 365 nm excitation source is not standardized.

Matrix-based color measurement corrections of tristimulus colorimeters.

For colorimetric imaging the tristimulus technique is still the best practical method to keep the measurement time within reasonable limits. However, the achievable color measurement uncertainties for special sources can be large. It is described how the systematic errors can be significantly reduced by using matrix-based color corrections and how the matrix elements can be optimized to obtain the smallest spectral mismatch errors for different light-source distributions.

Thermodynamic-temperature determinations of the Ag and Au freezing temperatures using a detector-based radiation thermometer.

The development of a radiation thermometer calibrated for spectral radiance responsivity using cryogenic, electrical-substitution radiometry to determine the thermodynamic temperatures of the Ag- and Au-freezing temperatures is described. The absolute spectral radiance responsivity of the radiation thermometer is measured in the NIST Spectral Irradiance and Radiance Responsivity Calibrations using Uniform Sources (SIRCUS) facility with a total uncertainty of 0.15% (k=2) and is traceable to the electrical watt, and thus the thermodynamic temperature of any blackbody can be determined by using Planck radiation law and the measured optical power.

Facility for spectral irradiance and radiance responsivity calibrations using uniform sources.

Detectors have historically been calibrated for spectral power responsivity at the National Institute of Standards and Technology by using a lamp-monochromator system to tune the wavelength of the excitation source. Silicon detectors can be calibrated in the visible spectral region with combined standard uncertainties at the 0.1% level.

Design and characterization of a photometer-colorimeter standard.

A photometer and tristimulus colorimeter has been developed at the National Institute of Standards and Technology (NIST) to realize a color scale. A novel construction was developed to implement the spectral-responsivity-based scale with small uncertainty. The new device can be used as a reference illuminance and luminance meter as well.

Development of a Tunable LED-Based Colorimetric Source.

A novel, spectrally tunable light-source utilizing light emitting diodes (LEDs) for radiometric, photometric, and colorimetric applications is described. The tunable source can simulate standard sources and can be used as a transfer source to propagate photometric and colorimetric scales from calibrated reference instruments to test artifacts with minimal increase in uncertainty. In this prototype source, 40 LEDs with 10 different spectral distributions were mounted onto an integrating sphere.