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Search Publications by: Yoshi Ohno (Fed)

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Displaying 51 - 75 of 197

Measurement of Solid-State-Lighting Products

July 11, 2007
Author(s)
Yoshihiro Ohno, Carl C. Miller
This paper discusses issues of photometric measurements of solid-state-lighting (SSL) products, for quantities including luminous flux, luminous efficacy, luminous intensity distribution, and color characteristics. Standards for SSL products are urgently

New Photometer Standards for Low Uncertainty Illuminance Scale Realization

July 11, 2007
Author(s)
George P. Eppeldauer, Carl C. Miller, Yoshihiro Ohno
Improved performance photometers have been developed at the National Institute of Standards and Technology (NIST) to utilize the low spectral responsivity uncertainty of spectral irradiance responsivity measurements performed on the facility of Spectral

Correction of Stray Light In Spectroradiometers and Imaging Instruments

July 4, 2007
Author(s)
Yuqin Zong, Steven W. Brown, Keith R. Lykke, Yoshihiro Ohno
Measurement errors from stray light, spectral or spatial, are inevitable and are often the dominant source of error in spectroradiometers and imaging radiometers/photometers. We have developed a simple matrix method for correcting spatial stray light in

Measuring Color Quality of Light Sources

August 17, 2006
Author(s)
Wendy L. Davis, Yoshihiro Ohno
The successful commercialization of solid-state lighting for general illumination will require an effective method to characterize the color quality of these sources. The distinctive spectral characteristics of solid-state lighting sources present both

Evaluation of Color Difference Formulae for Color Rendering Metrics

May 20, 2006
Author(s)
Wendy L. Davis, Yoshihiro Ohno
Solid-state lighting is providing strong incentive to develop a new color rendering or color quality metric for sources of general illumination. Differences in perceived color between reflective samples illuminated by the test lamp and a reference source

Chapter A.2.1 Photometry, Handbook of Optoelectronics

May 17, 2006
Author(s)
Yoshihiro Ohno
General introduction to photometry, radiometry, and colorimetry is given. The chapter consists of the following sections:1. Introduction2. Basis of Physical Photometry (2.1 Visual response, 2.2 Photometric base unit the candela)3. Quantities and Units in

Development of the NIST Detector-based Color Temperature Scale

May 17, 2006
Author(s)
George P. Eppeldauer, Yoshihiro Ohno
Based on the spectral responsivity of the channels of a tristimulus colorimeter, a color temperature scale is being developed at NIST. The low uncertainty of the spectral responsivity measurements can dominate the chromaticity measurement uncertainty. New

Simple Spectral Stray Light Correction Method for Array Spectroradiometers

February 20, 2006
Author(s)
Yuqin Zong, Steven W. Brown, Bettye C. Johnson, Keith R. Lykke, Yoshihiro Ohno
In many applications, the measurement accuracy of spectroradiometers, particularly instruments with a single dispersive element, is limited by the presence of stray radiation within the instrument. A simple, practical method has been developed to correct a

Optical Metrology for LEDs and Solid State Lighting

February 10, 2006
Author(s)
Yoshihiro Ohno
The performance of Light Emitting Diodes (LEDs), including efficiency, flux level, lifetime, and the variation of color, is advancing at a remarkable pace. LEDs are increasingly used for many applications including automotive, aviation, display

Development of a Color Quality Scale

February 8, 2006
Author(s)
Wendy L. Davis, Yoshihiro Ohno
A new metric for evaluating the color quality of light sources is being developed at NIST, in close contact with the lighting industry and the CIE. The current CIE Color Rendering Index (CRI) is outdated and has several known deficiencies. The CRI only

Calibration and Characterization of UV Sensors for Water Disinfection

January 2, 2006
Author(s)
Thomas C. Larason, Yoshihiro Ohno
Ultraviolet radiation (UV) effectively inactivates common pathogens found in ground and surface waters such as Cryptosporidium, Giardia, and most bacterial pathogens (e. g., E. coli). Water treatment facilities recently started using ultraviolet radiation

Correction of Stray Light in Spectrographs: Implications for Remote Sensing

August 22, 2005
Author(s)
Yuqin Zong, Steven W. Brown, Bettye C. Johnson, Keith R. Lykke, Yoshihiro Ohno
Spectrographs are used in a variety of applications in the field of remote sensing for radiometric measurements due to the benefits of measurement speed, sensitivity, and portability. However, spectrographs are single grating instruments that are

Spectral Matching With an LED-Based Spectrally Tunable Light Source

August 4, 2005
Author(s)
Irena Fryc, Steven W. Brown, Yoshihiro Ohno
A spectrally tunable light source using a large number of LEDs and an integrating sphere has been designed and constructed at the National Institute of Standards and Technology (NIST). The source is designed to have a capability of producing any visible