Route to higher fidelity FT-IR imaging

Rohit Bhargava, Shi Qing Wang, Jack L. Koenig

Research output: Contribution to journalArticle

Abstract

FT-IR imaging employing a focal plane array (FPA) detector is often plagued by low signal-to-noise ratio (SNR) data. A mathematical transform that re-orders spectral data points into decreasing order of SNR is employed to reduce noise by retransforming the ordered data set using only a few relevant data points. This approach is shown to result in significant gains in terms of image fidelity by examining microscopically phase-separated composites termed polymer dispersed liquid crystals (PDLCs). The actual gains depend on the SNR characteristics of the original data. Noise is reduced by a factor greater than 5 if the noise in the initial data is sufficiently low. For a moderate absorbance level of 0.5 a.u., the achievable SNR by reducing noise is greater than 100 for a collection time of less than 4 min. The criteria for optimal application of a noise-reducing procedure employing the minimum noise fraction (MNF) transform are discussed and various variables in the process quantified. This noise reduction is shown to provide high-quality images for accurate morphological analysis. The coupling of mathematical transformation techniques with spectroscopic Fourier transform infrared (FT-IR) imaging is shown to result in high-fidelity images without increasing collection time or drastically modifying hardware.

Original languageEnglish (US)
Pages (from-to)486-495
Number of pages10
JournalApplied Spectroscopy
Volume54
Issue number4
DOIs
StatePublished - Apr 2000

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Infrared imaging
Signal to noise ratio
Fourier transforms
routes
signal to noise ratios
Focal plane arrays
Liquid crystal polymers
Noise abatement
Image quality
Mathematical transformations
focal plane devices
Detectors
noise reduction
Hardware
Composite materials
hardware
liquid crystals
composite materials
detectors
polymers

ASJC Scopus subject areas

  • Instrumentation
  • Spectroscopy

Cite this

Route to higher fidelity FT-IR imaging. / Bhargava, Rohit; Wang, Shi Qing; Koenig, Jack L.

In: Applied Spectroscopy, Vol. 54, No. 4, 04.2000, p. 486-495.

Research output: Contribution to journalArticle

Bhargava, Rohit ; Wang, Shi Qing ; Koenig, Jack L. / Route to higher fidelity FT-IR imaging. In: Applied Spectroscopy. 2000 ; Vol. 54, No. 4. pp. 486-495.
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