Patent Document ID: 5513642
Application ID: 08321733
Patent Flag: 1

Claim One:
1. A method for determining the content of chemical constituents in a medium through light reflectance comprising the steps of: providing a probe comprising a light source and a plurality of photodetector strips circumferentially spaced around the light source and at different separation distances between the light source and each photodetector strip; selecting a wavelength for illumination of the photodetector strips; uniformly illuminating the photodetector strips at the selected wavelength; taking a test voltage reading from each photodetector strip; placing the probe on a surface of the medium; illuminating the medium at the selected wavelength using the light source; taking a voltage reading from each photodetector strip; adjusting the voltage reading from each photodetector strip by dividing the voltage reading by the test voltage reading from each photodetector strip; taking the logarithm of the adjusted voltage reading where S'(r) is the logarithm of the adjusted voltage reading as a function of the separation distance r between each photodetector strip and the light source; filtering values from the logarithmic function according to the formula: ##EQU3## where S(r) are the filtered values, r.sub.i is the distance from the light source to a photodetector strip i and N is a value based on a smoothing approximation, including N=zero; and using the filtered values as an indication of the content of chemical constituents in the medium.