... This paper describes various methods for the analysis of spectroscopic data, particularly as they relate to wavelength calibration of echelle-format spectra. ... Keywords: spectroscopy, Hough transform, wavelet transform, robust regression, echelle, wavelength calibration . ... Wavelet transform can be useful in complementing robust techniques for multiresolution analysis, and Section 4 presents an application of the Mexican hat transform to the detection of spectral features. ...