Irradiance Independent Spectrum Reconstruction from Camera Signals Using the Interpolation Method.

Area of Science:

• * Computational imaging
• * Color science
• * Spectrometry

Background:

• * Camera spectral reconstruction often relies on look-up table (LUT) methods.
• * Standard LUT methods are irradiance-dependent, limiting their use in variable lighting.
• * Recovering spectral reflectance accurately under changing irradiance is challenging.

Purpose of the Study:

• * To develop an irradiance-independent look-up table (II-LUT) method for spectral reconstruction.
• * To enable accurate spectral reflectance recovery in diverse field applications.
• * To improve computational efficiency in spectral analysis.

Main Methods:

• * Proposed an II-LUT method interpolating spectra in normalized signal space.
• * Utilized Munsell color chips under D65 illumination as reference samples.
• * Tested the method with tricolor and quadcolor cameras.

Main Results:

• * Achieved irradiance-independent spectral reconstruction.
• * Demonstrated significant computation time savings.
• * Introduced a trade-off between accuracy and computational speed, with potential for lower actual error in variable conditions.
• * Outperformed weighted principal component analysis in accuracy and speed.

Conclusions:

• * The II-LUT method provides a viable solution for irradiance-independent spectral reconstruction.
• * Offers a practical approach for applications with fluctuating light conditions.
• * Presents a favorable balance of accuracy, speed, and error reduction compared to existing methods.