Method of calibrating a spectral sensing device

A method of calibrating a spectral sensing device, the spectral sensing device comprising:

• a. at least one detector element configured for generating at least one detector signal in response to an illumination of the detector element by incident light;
• b. at least one wavelength-selective element configured for transferring incident light within at least one selected wavelength range onto the detector element;
• c. at least one light source configured for emitting light in at least one optical spectral range;
• d. at least one sample interface configured for allowing light from the light source to illuminate at least one sample and configured for allowing light from the sample to propagate via the wavelength-selective element to the detector element;
• e. at least one first optical path, wherein the first optical path is configured for allowing light emitted from the light source to propagate via the wavelength-selective element to the detector element without passing the sample interface;
• and
• f. at least one second optical path, wherein the second optical path is configured for allowing light emitted from the light source to propagate via the wavelength-selective element to the detector element by passing the sample interface at least once;
• the method comprising:
• I. illuminating the detector element via the at least one first optical path to obtain at least one first detector signal;
• II. illuminating the detector element via the at least one second optical path with no sample applied to the sample interface to obtain at least one open port detector signal;
• III. illuminating the detector element via the at least one second optical path with at least one calibration sample applied to the sample interface to obtain at least one calibration detector signal;
• and
• IV. determining at least one item of calibration information by using the first detector signal, the open port detector signal and the calibration detector signal.