Development of Infrared Library Search Prefilters for Automotive Clear Coats from Simulated Attenuated Total
Undugodage Don Nuwan Perera1, Koichi Nishikida2, Barry K Lavine1
11 Department of Chemistry, Oklahoma State University, Stillwater, OK, USA.
Applied Spectroscopy
|February 10, 2018
Summary
An attenuated total reflection (ATR) simulation algorithm enhances searching of infrared (IR) transmission libraries. This method accurately identifies automotive assembly plants using clear coat ATR spectra, improving spectral matching.
Area of Science:
- Forensic Science
- Analytical Chemistry
- Materials Science
Background:
- Infrared (IR) spectroscopy is crucial for material identification, but spectral library searching can be challenging.
- Attenuated total reflection (ATR) spectroscopy is a common sampling technique for solid materials like automotive paints.
- Distortions in ATR spectra can hinder accurate comparison with transmission IR spectral databases.
Purpose of the Study:
- To evaluate an ATR simulation algorithm's effectiveness in enhancing IR transmission spectral library searches.
- To develop and apply search prefilters derived from simulated ATR spectra for automotive paint analysis.
- To determine the feasibility of identifying vehicle assembly plants based on clear coat ATR spectra.
Main Methods:
- An existing ATR simulation algorithm was used to transform IR transmission spectra into simulated ATR spectra.
- Search prefilters were created from the fingerprint region (1500-500 cm⁻¹) of simulated ATR spectra.
- Discrete wavelet transform was employed for preprocessing both simulated and experimental ATR spectra to improve signal-to-noise ratio.
Main Results:
- A training set of 456 IR transmission spectra from 22 General Motors assembly plants was simulated into ATR spectra.
- Search prefilters developed from simulated ATR spectra successfully classified experimental ATR spectra of 14 clear coat samples.
- The ATR simulation algorithm facilitated accurate spectral library matching between ATR and transmission IR spectra of automotive clear coats.
Conclusions:
- The ATR simulation algorithm effectively mitigates spectral distortions, enabling successful library matching against transmission IR databases.
- This approach allows for the identification of automotive assembly plants by analyzing the clear coat layer's ATR spectra.
- The developed method offers a valuable tool for forensic analysis and quality control in the automotive industry.
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