&lt;title&gt;Far Infrared Imagery&lt;/title&gt;

Barker, D. H.; Hodges, D. T.; Hartwick, T. S.

doi:10.1117/12.954526

Cited by 17 publications

(3 citation statements)

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“…It is likely that the better agreement for the tooth results is related to the low levels of hydration in the tooth samples, while measurements in skin are likely to vary substantially without careful control of measuring conditions. Absorption coefficient results obtained were of the same order of magnitude as the early, incoherent, measurements reported by Barker et al 20 , and rank in the same order. Although reflection losses were included in their attenuation coefficients, the values for bone and fat are lower than those reported here, and not higher as might be expected.…”

Section: Discussionsupporting

confidence: 75%

Optical properties of tissue measured using terahertz-pulsed imaging

et al. 2003

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The first demonstrations of terahertz imaging in biomedicine were made several years ago, but few data are available on the optical properties of human tissue at terahertz frequencies. A catalogue of these properties has been established to estimate variability and determine the practicality of proposed medical applications in terms of penetration depth, image contrast and reflection at boundaries. A pulsed terahertz imaging system with a useful bandwidth 0.5-2.5 THz was used. Local ethical committee approval was obtained. Transmission measurements were made through tissue slices of thickness 0.08 to 1 mm, including tooth enamel and dentine, cortical bone, skin, adipose tissue and striated muscle. The mean and standard deviation for refractive index and linear attenuation coefficient, both broadband and as a function of frequency, were calculated. The measurements were used in simple models of the transmission, reflection and propagation of terahertz radiation in potential medical applications. Refractive indices ranged from 1.5 ± 0.5 for adipose tissue to 3.06 ± 0.09 for tooth enamel. Significant differences (P<0.05) were found between the broadband refractive indices of a number of tissues. Terahertz radiation is strongly absorbed in tissue so reflection imaging, which has lower penetration requirements than transmission, shows promise for dental or dermatological applications.

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Section: Discussionsupporting

confidence: 75%

Optical properties of tissue measured using terahertz-pulsed imaging

et al. 2003

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“…The potential of technical imaging in the veryfar-infrared (FIR) range has been considered as early as 1975. Owing to the lack of easy-to-use sources at that time this topic had not been pursued past an initial proof of principle [9]. Recent advancements in ultrashort electromagnetic pulse generation has revived this subject [10,11].…”

Section: Chemical Recognition In Terahertz Imagingmentioning

confidence: 99%

Chemical recognition in terahertz time-domain spectroscopy and imaging

Fischer

Hoffmann

Helm

et al. 2005

Semicond. Sci. Technol.

262

126

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In this paper, we present an overview of chemical recognition with ultrashort THz pulses. We describe the experimental technique and demonstrate how signals for chemical recognition of substances in sealed containers can be obtained, based on the broadband absorption spectra of the substances. We then discuss chemical recognition in combination with THz imaging and show that certain groups of biological substances may give rise to characteristic recognition signals. Finally, we explore the power of numerical prediction of absorption spectra of molecular crystals and illuminate some of the challenges facing state-of-the-art computational chemistry software.

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“…All objects at temperatures above absolute zero radiate energy in the form of electromagnetic waves and absorb and reflect energy that is incident upon them. A perfect absorber is calied a blackbody which is a perfect radiator and has an omission spectrum completely governed by the absolute physical temperature T. The brightness of the radiation is given by Planck's radiation law as follows: 2hv 3 (1) In Fig. 1, several brightness curves are plotted as a function of frequency and temperature using Eq.…”

Section: Radiometry Fundamentalsmentioning

confidence: 99%

Safeguards applications of far infrared radiometric techniques for the detection of contraband

Hodges¹,

Reber²,

Foote³

et al. 1980

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A new safeguards system under development employs radiometers in the 100-300 GHz spectral band to detect contraband, including shielding materials (used to attenuate the gamma ray emissions from nuclear materials), weapons, or explosives covertly concealed on personnel. Clothing is highly transparent at these frequencies an^ imaging techniques can detect contraband by its emissivity and reflectivity differences relative to human tissues. Experimental data are presented and sample images are uss.i as a basis to discuss system advantages and limitations.

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<title>Far Infrared Imagery</title>

Abstract: Imaging experiments in the far infrared are described. Transmission data are presented for several common media. Far infrared pictures of metallic objects are presented. The practicality of a far infrared imaging system is discussed.

Cited by 17 publications

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Optical properties of tissue measured using terahertz-pulsed imaging

Optical properties of tissue measured using terahertz-pulsed imaging

Chemical recognition in terahertz time-domain spectroscopy and imaging

Safeguards applications of far infrared radiometric techniques for the detection of contraband

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