Analysis of Multi-Wavelength Pyrometry Using Non-Linear Chi-Square Fits and Monte Carlo Method

Conference · Fri Mar 01 04:00:00 EST 1991

OSTI ID:5967904

Gathers, G. R. ^[1]

---

1. Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)

An analysis of multi-wavelength pyrometry is made using Monte Carlo methods to evaluate the measurement error as a function of temperature for 3, 4, 5, and 6 channels. Both a graybody and an emissivity with linear wavelength dependence are considered. χ² is calculated using the observed intensity in each channel, and is minimized with respect to the temperature and the emissivity coefficients, using the Levenberg-Marquardt method. The influence of spectral span of the channels, and the weight function used in the χ² fit, are examined. For the case of linear wavelength dependence, the solutions are found to be non-unique, even with 6 channels. The results show little improvement of precision with increasing number of channels beyond 4 channels when the non-linear variable T is free. Both the spectral span and the weight function are shown to be important variables.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5967904
• Report Number(s): UCRL-JC--105620; CONF-9106176--1; ON: DE91011185
• Country of Publication: United States
• Language: English

Related Subjects

440500* -- Thermal Instrumentation-- (1990-)
47 OTHER INSTRUMENTATION
657000 -- Theoretical & Mathematical Physics
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
EMISSIVITY
HIGH TEMPERATURE
MEASURING INSTRUMENTS
MEASURING METHODS
MONTE CARLO METHOD
Monte Carlo
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
PYROMETERS
SURFACE PROPERTIES
TEMPERATURE MEASUREMENT
chi-square
high temperature
pyrometry