An improved waveguide for an infrared thermometer, comprising a silver halide optical fiber cable of low transmission loss, a high aspect ratio, and a radially decreasing index of refraction. The transmission loss is low enough to enable the cable to be up to ten meters in length, thereby extending beyond the housing of the thermometer and being insertable in confined spaces such as an ear canal. The small cross sectional area and radially decreasing index of refraction of the cable make the field of view of the cable small enough to enable it to resolve targets as small as a portion of the human tympanic membrane, enabling the device to be used to measure the core temperature of humans and other organisms.
An improved waveguide for an infrared thermometer, comprising a silver halide optical fiber cable of low transmission loss, a high aspect ratio, and a radially decreasing index of refraction. The transmission loss is low enough to enable the cable to be up to ten meters in length, thereby extending beyond the housing of the thermometer and being insertable in confined spaces such as an ear canal. The small cross sectional area and radially decreasing index of refraction of the cable make the field of view of the cable small enough to enable it to resolve targets as small as a portion of the human tympanic membrane, enabling the device to be used to measure the core temperature of humans and other organisms.
A method of active radiometric thermometry. The target, whose temperature is to be measured, is heated briefly and locally, preferably by a pulse of laser radiation. The intensity of infrared or visible radiation emitted by the heated portion of the target is measured as a function of time. The temperature of the target is inferred from the shape of the intensity curve of the emitted radiation as a function of time.