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Multi temporal regression method for mid infrared [3-5microm] emissivity outdoor
Optics Express
|June 3, 2009
Summary
This study introduces a new outdoor method for measuring surface reflectivity and emissivity in the 3-5 micrometer range. The technique achieves high accuracy, with an estimated measurement error of approximately 2%.
Area of Science:
- Radiometry
- Infrared Spectroscopy
- Materials Science
Background:
- Accurate determination of surface optical properties is crucial for various applications.
- Existing methods for measuring bi-directional reflectivity and emissivity in the 3-5 micrometer range face challenges in outdoor conditions.
- Infrared thermography offers a potential solution but requires robust measurement protocols.
Purpose of the Study:
- To develop and validate a reliable outdoor measurement protocol for surface bi-directional reflectivity and emissivity in the 3-5 micrometer region.
- To address issues related to direct inversion of radiometric signals and improve measurement stability.
- To assess the impact of systematic errors on measurement accuracy.
Main Methods:
- Conducted outdoor experimental measurements using radiometric infrared cameras in the 3-5 micrometer (band-2) and 8-14 micrometer (band-3) spectral regions.
- Acquired data through a sequence of sunlit and shade measurements, referencing a diffuse aluminum reflector for band-2 bi-directional reflectivity.
- Implemented a multitemporal method where the slope of a linear regression represents the surface emissivity.
Main Results:
- Direct inversion of the band-2 radiometric signal proved unstable, necessitating an alternative approach.
- The multitemporal method provided a stable and reliable estimation of surface emissivity.
- Detailed analysis identified and quantified sources of systematic errors, contributing to an estimated measurement error of around 2%.
Conclusions:
- The proposed multitemporal method demonstrates significant potential for accurate outdoor determination of surface bi-directional reflectivity and emissivity in the 3-5 micrometer band.
- The developed protocol, utilizing diffuse aluminum reflectors and specific measurement sequences, enhances measurement stability and accuracy.
- The findings suggest that this method can achieve a measurement error within 2%, making it suitable for various scientific and industrial applications.
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