Abstract:
There is described a system and method for the in vivo determination of lactate levels in blood using Near-Infrared Spectroscopy (NIRS)and/or Near-infrared Raman Spectroscopy (NIR-RAMAN). The method teaches measuring lactate in vivo comprising: optically coupling a body part (14) with a light source (10) and a light detector (18) the body part having tissues comprising blood vessels; injecting near-infrared (NIR) light at one or a plurality of wavelengths in the body part; detecting, as a function of blood volume variations in the body part, light exiting the body part at at least the plurality of wavelengths to generate an optical signal (20); and processing the optical signal as a function of the blood volume variations to obtain a lactate level in blood.
Abstract:
A spectral reflectance sensor including: a light source for emitting a modulated beam of red light; a light source for emitting a modulated beam of near infrared light; a receiver for receiving reflected light produced by either the red source or the near infrared source; a receiver for receiving incident light from either the red source or the infrared source; a signal conditioner responsive to the modulation such that the signals produced by the receivers in response to reflected and incident light from the source can be discriminated from signals produced by ambient light; and a microprocessor having an input such that the microprocessor can determine the intensities of incident red light, reflected red light; incident near infrared light; and reflected near infrared light. From these intensities, and by knowing the growing days since emergence or planting, the sensor can calculate the mid-growing season nitrogen fertilizer requirements of a plant.
Abstract:
The water detecting apparatus (2) has a source (10) of infra-red radiation which is reflected off the inner surface (12) of a pipe wall (14) onto a mirror (16) directing the infra-red signal along a path (18) to an infra-red detector (22) connected by an electrical signal path (24) to an electronic control (26). The path (18) is interrupted by a rotating chopper (28) having windows occupied by two optical filters (34 and 36). The filter (34) only passes an infra-red signal of wavelength 1900 nm. (nanometres) which is absorbed by water, whilst the filter (36) only passes an infra-red signal of wavelength 2200 nm. another wavelength absorbed by water but not to the same extent as the 1900 nm. wavelength. The 2200 nm. wavelength serves as a reference signal. When the strength of the infra-red signal passed by filter (34) decreases in relation to the strength of the infra-red reference signal passed by filter (36), this is due to water on the surface (12) absorbing the 1900 nm. wavelength more than the 2200 nm., and the control (26) causes indicator (6) to indicate the presence of the water.
Abstract:
Method and apparatus for detecting, by absorption spectroscopy, an isotopic ratio of a sample, by passing first and second laser beams of different frequencies through the sample. Two IR absorption cells are used, a first containing a reference gas of known isotopic ratio and the second containing a sample of unknown isotopic ratio. An interlacer or reflective chopper may be used so that as the laser frequencies are scanned the absorption of the sample cell and the reference cell are detected alternately. This ensures that the apparatus is continuously calibrated and rejects the baseline noise when phase sensitive detection is used.