| 释义 |
reflectance Physics.|rɪˈflɛktəns|
[f. reflect v. + -ance.]
The proportion of the light incident upon a surface, which is reflected or scattered by it; spec. a complex number whose modulus is the proportion of the radiant flux (at some specified wavelength or range of wavelengths) which is reflected, and whose argument indicates the change of phase undergone by the reflected light. Cf. reflection coefficient, factor. Also attrib.
1926Jrnl. Optical Soc. Amer. X. 178 Reflectance..is the ratio of reflected to incident radiant energy. 1932[see infra-red a. and n. A. 1]. 1956Nature 14 Jan. 74/2 The assessment of particular reflectance characteristics of cotton may be made on the automatic Nickerson–Hunter cotton colorimeter. 1957V. J.-R. Kehoe Technique Film & Television Make-Up viii. 96 Black velvet has approximately 2 per cent reflectance, while some white paper is as high as 90 per cent. 1960Illuminating Engin. LV. 228/1 The concepts of transmittance and reflectance can be extended to cover the separation of specular and diffuse components which are functions of angles. 1975D. H. Burrin in Williams & Wilson Biologist's Guide to Princ. & Techniques Pract. Biochem. v. 138 Reflectance spectrophotometers, which measure the radiation absorbed when a light beam is reflected by the sample, allow the determination of absorption spectra of pastes and suspensions of micro⁓organisms which are too opaque to transmit radiation. 1977J. Hedgecoe Photographer's Handbk. 132 (caption) Meter reads direct off mid-gray (ideally 16 percent reflectance) card which simulates subject mid-tone. |