Optimal thermometry theory of three-channel wide spectrum based on three-directional difference

Area of Science:

• Physics
• Thermodynamics
• Optical Engineering

Background:

• Current wide-spectrum thermometry is limited by the assumption of constant spectral emissivity, degrading accuracy.
• This limitation creates a deadlock, preventing concurrent achievement of high analytical capability and resolution accuracy in radiation thermometry.

Purpose of the Study:

• To propose a novel wide spectral optimization temperature solution theory to address accuracy degradation in radiation thermometry.
• To decouple and invert multi-channel spectral emissivity, removing the dependency on constant emissivity assumptions.

Main Methods:

• Utilizing Taylor series de-integration and focusing on spectral emissivity's first and second derivatives.
• Developing a three-directional difference method for wide spectral optimization.
• Analyzing the impact of differential methods on spectral emissivity derivatives.

Main Results:

• The proposed theory ensures stable solving conditions for imaging systems.
• Successfully decoupled and inverted three-channel spectral emissivity.
• Experimental monitoring of temperature rise showed maximum average relative errors below 6% and 5% for different samples.
• Accurately reproduced spectral emissivity variation rates and trends, consistent with simulations.

Conclusions:

• The new theory fundamentally removes the dependency on constant spectral emissivity treatment.
• Achieved significant improvements in temperature accuracy and spectral emissivity inversion for wide-spectrum thermometry.
• Demonstrated the practical applicability of the method in monitoring dynamic temperature changes.