Spectrometric optical method and system providing required signal-to-noise of measurements
First Claim
1. A method for use in spectrometric measurements of an article using an optical system having an illumination system and a light detection system, the method comprising selecting an optimal integration time range of the light detection system during which the measurement is to be applied, said optimal integration time being that at which a required value of signal to noise ratio (SNR) of the measurements is obtainable, wherein the optimal integration time is determined using an a priori known value of a spectral reflectance of the article, and a pre-defined spectral characteristic of the measurement system, said optimal integration time being selected such that the highest value of a measured signal is slightly lower than a signal corresponding to a saturation level of the detection system, while the lowest value of the measured signal corresponds to a value of the SNR slightly above the required SNR value.
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Abstract
A system and method for use in spectrometric measurements of an article using selecting an optimal integration time range of the light detection system during which the measurement is to be applied, the optimal integration time being that at which a required value of signal to noise ratio (SNR) of the measurements is obtainable.
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Citations
14 Claims
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1. A method for use in spectrometric measurements of an article using an optical system having an illumination system and a light detection system, the method comprising selecting an optimal integration time range of the light detection system during which the measurement is to be applied, said optimal integration time being that at which a required value of signal to noise ratio (SNR) of the measurements is obtainable, wherein the optimal integration time is determined using an a priori known value of a spectral reflectance of the article, and a pre-defined spectral characteristic of the measurement system, said optimal integration time being selected such that the highest value of a measured signal is slightly lower than a signal corresponding to a saturation level of the detection system, while the lowest value of the measured signal corresponds to a value of the SNR slightly above the required SNR value.
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2. A method for use in spectrometric measurements of an article using an optical system having an illumination system and a light detection system, the method comprising selecting an optimal integration time range of the light detection system during which the measurement is to be applied, said optimal integration time being that at which a required value of signal to noise ratio (SNR) of the measurements is obtainable, wherein said selecting of the optimal integration time range comprises applying a preliminary spectral measurement with a relatively small integration time value such that at least one intensity value of the preliminary measured signal is higher than that corresponding to a predetermined minimal value of the SNR, thereby allowing to determine the reflectance of the article under measurements and calculate the optimal value for the integration time needed for the actual measurement in said article, said optimal integration time being selected such that the highest value of a measured signal is slightly lower than a signal corresponding to a saturation level of the detection system, while the lowest value of the measured signal corresponds to a value of the SNR slightly above the required SNR value.
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3. A method for use in spectrometric measurements of an article using an optical system having an illumination system and a light detection system having a limited dynamic range, the measurement system having highly non-uniform spectral characteristics, the method comprising selecting an optimal integration time range of the light detection system during which the measurement is to be applied, said optimal integration time being that at which a required value of signal to noise ratio (SNR) of the measurements is obtainable, said optimal integration time being selected such that the highest value of a measured signal is slightly lower than a signal corresponding to a saturation level of the detection system, while the lowest value of the measured signal corresponds to a value of the SNR slightly above the required SNR value, wherein said selecting of the optimal integration time range comprises applying first and second sequential preliminary measurements to the article using a certain integration time, one of said first and second measurements being such that the highest value of the measured signal being below the saturation level while a part of the measured signal being under the minimal SNR level;
- and the other measurement being such that the lowest value of the corresponding measured signal being above the minimal SNR level while a part of said signal being in saturation.
- View Dependent Claims (4, 5, 6, 7, 8)
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9. A spectrometric optical system, comprising an illumination system, and a light detection system, the illumination system comprising first and second illuminators operating with different wavelength ranges producing together light of a wavelength range of about 180-950 nm;
- and a control unit connectable to the illumination and detection systems to control the operation of the illumination and detection systems, the control unit being configured to apply at least one preliminary measurement to an article and to select an optimal integration time range of the light detection system during which an actual measurement is to be applied to said article, said optimal integration time being that at which a required value of signal to noise ratio (SNR) of the measurements is obtainable.
- View Dependent Claims (10, 11, 12, 13, 14)
Specification