Raman spectral analysis integrated with multivariate calibration is a fast and effective solution to monitor chemical product properties. However, Raman instruments utilizing charge-coupled device (CCD) detectors suffer from occasional spikes caused by cosmic rays. Cosmic spikes can disturb or even destroy the meaningful chemical information expressed by normal Raman spectra. In online monitoring, some cosmic spikes have intensity and bandwidth similar to normal Raman peaks of chemical components when a low resolution and cost-effective Raman instrument is used. Moreover, the online Raman spectra always contain variations of strong Raman peaks and fluorescence. Current spike-removal methods seem to have difficulty detecting and recovering cosmic spikes in these online Raman spectra. Therefore, an improved algorithm is proposed. In this algorithm, a new scheme composed of intensity identification and local moving window correlation analysis is introduced for cosmic spike detection; intensity identification based on derivative spectra and local linear fitting approximation are used for the recovery of cosmic spikes. The algorithm is proved to be simple and effective and has been applied in an online Raman instrument installed at a continuous catalytic reforming unit in a refinery.
Vol. 7, Iss. 1 Virtual Journal for Biomedical Optics
Sheng Li and Liankui Dai, "An Improved Algorithm to Remove Cosmic Spikes in Raman Spectra for Online Monitoring," Appl. Spectrosc. 65, 1300-1306 (2011)
References are not available for this paper.
OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.