文档介绍：A new method for determining the emissivity of
the human skin in vivo
Francisco J. Sanchez-Marin
Medical Optics
Center of Research in Optics
Leon, Mexico
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Abstract—To determine the radiation emmitted by the human skin, [7]. Taking into account that for wavelengths beyond 5 μm the
the emissivity of its surface must be known. In this work is transmissivity of the human skin is practically zero [5, 6, 8],
presented a new procedure to measure the emissivity of the human and that with ambient temperatures close to that of the object
skin in vivo. The proposed method is based in the calculation of the of interest (. the monitored area), the reflected radiation
difference of two images: one acquired before projecting a laser
beam on the surface of the skin, and the other alter such projection. es significant, Kirchhoff’s law can be written as [9]:
The resulting “difference image” contains only the reflected
radiation, which is used to calculate the emissivity of the skin ε 0 = 1−ρ n0 , [1]
making use of the Kirchhoff’s law and the Helmoholtz reciprocity a a
relation. With this method non-contact measurements are made,
and the temperature of the skin is not required. Additionally, with where ε is emissivity, ρ is reflectivity, subscripts refer to
the proposed method it is possible to determine the emissivity of the element