Intensity-Preserving Robust Fusion for Multi-Frame Spatial Heterodyne Spectral Recovery Toward Atmospheric Remote Sensing

Compact spatial heterodyne spectroscopy (SHS) is useful for atmospheric remote sensing, but repeated interferogram acquisition alone does not guarantee stable recovered spectral intensity. An intensity-preserving framework based on self-calibrated quality-gated robust fusion (SC-QGRF) was evaluated for multi-frame SHS spectral recovery. Frame weights are derived from image and spectral quality descriptors while avoiding framewise spectral normalization. Test spectral measurements were carried out using potassium and xenon lamps, which served as controlled laboratory cases for line spectrum and broadband spectrum recovery, respectively. Random Single, Image Average, Spectrum Mean, Spectrum Median, and the proposed strategy were compared under a common recovery and evaluation setting. Complete frame and exposure response analyses retained the main spectral profiles and showed no evident exposure-dependent intensity bias in this laboratory setting. Repeated subsampling provided the main stability evidence. SC-QGRF achieved the lowest variability in all four core metrics: coefficient of variation (CV) of K-AreaRatio = 0.0445%, CV of the full width at half maximum of the second K peak (K-FWHM2) = 0.0395%, CV of Xe-BandIntegral = 1.1770%, and standard deviation (STD) of Xe-SpectralCentroid = 0.0786 nm. The method can be used as a spectral quality control and fusion step for repeated SHS observations toward atmospheric remote sensing, while gas cell and field measurements remain necessary for retrieval-level validation.