A liquid crystal tunable filter based shortwave infrared spectral imaging system: Calibration and characterization

Weilin Wang, Changying Li, Ernest W. Tollner, Glen Christopher Rains, Ronald D. Gitaitis

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Calibration is a critical step for developing spectral imaging systems. This paper presents a systematic calibration and characterization approach for a liquid crystal tunable filter (LCTF) based shortwave infrared (SWIR) spectral imaging system. A series of tests were conducted to validate the linearity of the system output, measure the field of view of the spectral imager, increase the system spectral sensitivity, test the spatial and spectral resolution of the system, evaluate the system stability and image distortion, and reduce the spectral noise of the system output. Results showed that the system had an angle of view of 6.98° and a spatial resolution of 158 μm. The spectral sensitivity of the system was corrected by controlling the camera exposure time and gain, which increased the signal to noise ratio of the system by 16.5%. Test results also verified the system spectral accuracy and linearity (r> 0.999). The system output was proven to be stable and image distortion was not perceivable. Results of calibration tests indicated that this system satisfied the design criteria in both spatial and spectral domains. The calibration methods presented here are applicable to the LCTF-based spectral imaging systems in other applications.

Original languageEnglish
Pages (from-to)135-144
Number of pages10
JournalComputers and Electronics in Agriculture
Volume80
DOIs
Publication statusPublished - Jan 1 2012

Fingerprint

Imaging systems
Liquid crystals
calibration
image analysis
Calibration
crystal
filter
Infrared radiation
liquid
linearity
spatial resolution
testing
Spectral resolution
field of view
spectral resolution
System stability
Image sensors
cameras
signal-to-noise ratio
exposure duration

All Science Journal Classification (ASJC) codes

  • Forestry
  • Agronomy and Crop Science
  • Computer Science Applications
  • Horticulture

Cite this

A liquid crystal tunable filter based shortwave infrared spectral imaging system : Calibration and characterization. / Wang, Weilin; Li, Changying; Tollner, Ernest W.; Rains, Glen Christopher; Gitaitis, Ronald D.

In: Computers and Electronics in Agriculture, Vol. 80, 01.01.2012, p. 135-144.

Research output: Contribution to journalArticle

Wang, Weilin ; Li, Changying ; Tollner, Ernest W. ; Rains, Glen Christopher ; Gitaitis, Ronald D. / A liquid crystal tunable filter based shortwave infrared spectral imaging system : Calibration and characterization. In: Computers and Electronics in Agriculture. 2012 ; Vol. 80. pp. 135-144.
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