A liquid crystal tunable filter based shortwave infrared spectral imaging system: Design and integration

Wang, Weilin; Li, Changying; Tollner, E. W.; Rains, Glen C.; Gitaitis, R. D.

doi:10.1016/j.compag.2011.07.012

Cited by 35 publications

(9 citation statements)

References 27 publications

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“…Nowadays, the world without liquid crystals' (LCs) technology is difficult to imagine. They have a lot of applications, for example, in LC displays [1], programmable lasers [2], and LC tunable filters [3]. Day by day the interest of electronic industry in LC increases that makes this field of studies also very interesting for scientists.…”

Section: Introductionmentioning

confidence: 99%

Electro-Steering Tapered Fiber-Optic Device with Liquid Crystal Cladding

et al. 2019

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The paper presents the results of design, manufacturing, and characterization of a hybrid broad band in-line fiber-optic device. It uses nematic liquid crystal as cladding with electro-steering properties in a biconical optical fiber taper structure. Liquid crystal mixtures denoted as 6CHBT and E7 are designed for electric as well as temperature control of electromagnetic wave propagation in a broad wavelength range. The applied taper with 10±0.5 μm diameters has losses lower than 0.5 dB in whole investigated spectrum range. Three kinds of initial liquid crystal molecules’ orientations (parallel, orthogonal, and twist) in relation to the light beam propagating in a taper were applied. The performance of a tuned cladding was studied at an electric field of the range of 0–190 V and the temperature range from 20°C up to 42°C and 59°C for 6CHBT and E7, respectively. The induced reorientation of liquid crystal molecules was measured at a broad wavelength range (550-1550 nm).

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Section: Introductionmentioning

confidence: 99%

Electro-Steering Tapered Fiber-Optic Device with Liquid Crystal Cladding

et al. 2019

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“…The samples of the first experiment were imaged using a hyperspectral imaging system previously built by the Bio-Sensing and Instrumentation Laboratory of the University of Georgia 25 . All images were acquired in a light chamber to avoid the interference of ambient light ( Fig.…”

Section: Methodsmentioning

confidence: 99%

Nondestructive Detection and Quantification of Blueberry Bruising using Near-infrared (NIR) Hyperspectral Reflectance Imaging

Takeda

2016

Sci Rep

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Currently, blueberry bruising is evaluated by either human visual/tactile inspection or firmness measurement instruments. These methods are destructive, time-consuming, and subjective. The goal of this paper was to develop a non-destructive approach for blueberry bruising detection and quantification. Experiments were conducted on 300 samples of southern highbush blueberry (Camellia, Rebel, and Star) and on 1500 samples of northern highbush blueberry (Bluecrop, Jersey, and Liberty) for hyperspectral imaging analysis, firmness measurement, and human evaluation. An algorithm was developed to automatically calculate a bruise ratio index (ratio of bruised to whole fruit area) for bruise quantification. The spectra of bruised and healthy tissues were statistically separated and the separation was independent of cultivars. Support vector machine (SVM) classification of the spectra from the regions of interest (ROIs) achieved over 94%, 92%, and 96% accuracy on the training set, independent testing set, and combined set, respectively. The statistical results showed that the bruise ratio index was equivalent to the measured firmness but better than the predicted firmness in regard to effectiveness of bruise quantification, and the bruise ratio index had a strong correlation with human assessment (R2 = 0.78 − 0.83). Therefore, the proposed approach and the bruise ratio index are effective to non-destructively detect and quantify blueberry bruising.

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“…(1)) implemented in Interactive Dynamic Language (IDL4.7, Exelis Visual Information Solutions, Boulder, CO, USA) (Wang et al, 2012b). White reference images were acquired from a white Spectralon panel with 99% reflectance (SRT-99-050, Labsphere Inc., North Sutton, NH, USA) and dark images were acquired by covering the lens of the camera completely.…”

Section: Short Wave Infrared Hyperspectral Imaging Systemmentioning

confidence: 99%

“…In addition, previous studies mostly used line-scan or push-broom scanning which required the object to move in a direction perpendicular to scanning lines so that the entire object can be imaged (Lu and Chen, 1998). Liquid crystal tunable filter (LCTF) based hyperspectral imaging system is an area-scan technique that captures spatial 2-D images at selected wavelengths sequentially and then stacks these images from different wavelengths together to form a 3-D hyperspectral image cube (Wang et al, 2012b). Compared to the line scan technique, the LCTF system does not require a moving sample and thus is especially suitable for developing a multispectral imaging system that can randomly access user-selected wavelengths.…”

Section: Introductionmentioning

confidence: 99%

A liquid crystal tunable filter based shortwave infrared spectral imaging system: Design and integration

Cited by 35 publications

References 27 publications

Electro-Steering Tapered Fiber-Optic Device with Liquid Crystal Cladding

Electro-Steering Tapered Fiber-Optic Device with Liquid Crystal Cladding

Nondestructive Detection and Quantification of Blueberry Bruising using Near-infrared (NIR) Hyperspectral Reflectance Imaging

Shortwave infrared hyperspectral reflectance imaging for cotton foreign matter classification

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