Patent ID: 9719852
Date: 2017-08-01
CPC Classifications: G01J

Claim:
1. A computer implemented method to compensate temperature induced light source drift in a spectrophotometer using a light measuring device having a processor, a memory, a light source configured to emit broad band light, a sample sensor configured to output a sample signal in response to light being incident upon the sensor, a reference sensor configured to output a reference signal in response to light being incident upon the reference sensor, and a calibration measurement application stored in the memory and executable by the processor, the method comprising the steps of: emitting a plurality of flashes of light from the light source such that the light is incident on a reference target and a calibration target, measuring, for each of the plurality of light flashes, the intensity of each wavelength of the light reflected off a calibration target using the sample sensor, and the intensity of the light reflected off a reference target using the reference sensor; transforming the measured values into a compensation coefficient value based on the relationship between the sample sensor measurement and the reference sensor measurement at each wavelength; obtaining a sample measurement of the intensity at different wavelengths of light reflected off of a sample under analysis with the sample sensor and a reference measurement of the intensity of light reflected off of the reference target; generating a corrected sample measurement according to a compensation algorithm that incorporates the compensation coefficient; and outputting the corrected sample signal.