Explanatory analysis of spectroscop0yic data using machine learning of simple, interpretable rules

摘要

Whole organism or tissue profiling by vibrational spectroscopy produces vast amounts of seemingly unintelligible data. However, the characterisation of the biological system under scrutiny is generally possible only in combination with modern supervised machine learning techniques, siuch as artificial neural networks (ANNs). Nevertheless, the interpretation of the calibration models from ANNs is often very difficult, and the information in terms of which vibrational modes in the infrared or Raman spectra are important is not readily available. ANNs are often perceived as 'black box' approaches to modelling spectra, and to allow the deconvolution of complex hyperspectral data it is necessary to develop a system that itself produces 'rules' that are readily comprehensible. Evolutionary computation, and in particular genetic programming (GP), is an ideal method to achieve this. An example of how GP can be used for Fourier tansform infrared (FT-IR) image analysis i9s presented, and is compared with images produced by principal components analysis (PCA), discriminant function analysis (DFA) and partial least squares (PLS) regression.