Removing Instrument Artifacts Without Touching the Science

Signal processingSpectroscopy

Reflectance spectrum after wavelet-based fringe correction — Asteroid (225) Henrietta's reflectance spectrum after wavelet defringing: the periodic detector artifact is gone, the broad mineral absorption features remain.

The question

Spectra from real instruments arrive contaminated. Periodic fringing from the detector overlays the faint mineral absorption features that carry the science, and smoothing aggressively destroys both together. How do you remove one and keep the other?

The approach

SpecReflect reduces raw telescope spectra to reflectance and applies wavelet-based defringing: the fringe pattern lives at characteristic scales, so a wavelet decomposition can isolate and subtract it while leaving broader spectral structure intact. The removed component is tracked explicitly, so nothing disappears silently.

The result

On asteroid (225) Henrietta, the corrected spectrum preserves the broad absorption features while the fringing drops into structureless residuals a factor of fifty below the signal, turning a contaminated observation into a publishable reflectance spectrum.

Tools: Python, NumPy, SciPy, astropy, wavelet decomposition

Read the code: SpecReflect on GitHub →