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Search Publications by: Yuqin Zong (Fed)

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Displaying 26 - 50 of 51

Analysis of Uncertainties in Stray-Light Correction

December 1, 2010
Author(s)
Yuqin Zong
Measurement errors arising from stray light within a spectroradiometer are often the dominant source of uncertainty and are difficult to reduce. However, the stray-light errors can be corrected by using a stray-light correction matrix that is derived from

MEASUREMENT OF WEIGHTED LED RADIANCE RELATED TO PHOTOBIOLOGICAL SAFETY

December 1, 2010
Author(s)
Tongsheng Mou, Yuqin Zong, Yoshi Ohno
Optical radiation safety of light-emitting diode (LED) products is being addressed in the International Electrotechnical Commission (IEC) standard document 62471-2006. Measurement of weighted radiance of LEDs, used to assess the maximal exposure related to

NIST SPECTRALLY TUNABLE LIGHTING FACILITY FOR COLOR RENDERING AND LIGHTING EXPERIMENTS

May 29, 2009
Author(s)
Carl C. Miller, Yoshihiro Ohno, Wendy L. Davis, Yuqin Zong, Kevin Dowling
The National Institute of Standards and Technology has developed a spectrally tunable lighting facility to allow state-of-the-art vision experiments on color rendering and lighting. The facility is composed of two cubicles, each lit by a spectrally tunable

f1' EVALUATION AND MEASUREMENT COMPARISON

October 1, 2008
Author(s)
Jiangen PAN, Haiping SHEN, Yuqin Zong, Yoshi Ohno
The mismatch of spectral responsivity to the CIE V(lambda) function, i. e., the f1' index, is the most critical characteristic of photometers and tristimulus colorimeters. The f1' value varies with measurement conditions, which is often omitted in the f1'

NEW PRACTICAL METHOD FOR MEASUREMENT OF HIGH-POWER LEDS

October 1, 2008
Author(s)
Yuqin Zong, Yoshihiro Ohno
The measurement of high-power light emitting diodes (LEDs) has been difficult because they are highly sensitive to thermal operating conditions, and there has been a lack of common methods that can be used by both LED manufactures and users to acquire

Derivation of the MODIS Aqua Point-Spread Function for Ocean Color Bands

September 11, 2008
Author(s)
Gerhard Meister, Yuqin Zong, Charles R. McClain
The Moderate Resolution Imaging Spectroradiometer (MODIS) on the Earth Observing System (EOS) Aqua platform has 9 spectral bands with center wavelengths from 412nm to 870nm that are used to produce the standard ocean color data products. Ocean scenes

PRACTICAL METHOD FOR MEASUREMENT OF AC-DRIVEN HIGH-POWER LEDS

July 14, 2008
Author(s)
Yuqin Zong, Yoshihiro Ohno, Pei-ting Chou
Alternating-current (AC) driven high-power LEDs are available and used in SSL products. AC LEDs operate directly from a mains supply and thus have advantages in simplifying product design, increasing product reliability, and extending product lifetime

Characterization and Correction of Stray Light in Optical Instruments

November 1, 2007
Author(s)
Yuqin Zong, Steven W. Brown, G Meister, R Barnes, Keith R. Lykke
Improperly imaged, or scattered, optical radiation within an instrument is difficult to properly characterize and is often the dominant residual source of measurement error. Scattered light can originate from the spectral components of a point source and

Evaluation of a Portable Hyperspectral Imager for Medical Imaging Applications

October 2, 2007
Author(s)
David W. Allen, Maritoni A. Litorja, Steven W. Brown, Joseph P. Rice, Yuqin Zong
Portable hyperspectral imagers are becoming commonly available as a commercial product. A liquid crystal tunable filter based CCD imager was evaluated and characterized for spectral stray light using a tunable laser facility. The hyperspectral imager is

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

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

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

Calibrations of Colorimeters for Display Measurements: Some Commercial Colorimeters Have Uncertainties in Display-Color Measurements That Are Too Large for Many Commercial, Industrial and Military Applications - But New NIST-Developed Calibration Proc...

December 1, 1999
Author(s)
Steven W. Brown, Yuqin Zong, Yoshihiro Ohno
Commercial color measuring instruments (colorimeters and spectroradiometers) are currently used in a number of product development and control environments, as well as for product acceptance testing and a variety of other applications. In many cases, the

Detector-Based Integrating Sphere Photometry

June 24, 1999
Author(s)
Yoshihiro Ohno, Yuqin Zong
A new luminous flux calibration facility using a 2.5 m integrating sphere has been developed at NIST. The Absolute Integrating-Sphere Method, developed for realization of the lumen in 1995, has been applied to routine calibration measurements of luminous