A user device comprising: a spectrometer module (to) adapted to acquire spectral information and output spectral data representing the acquired spectral information; a memory storing predetermined correction data for correcting the spectral data detected by the spectrometer module; and a processing unit, which is configured to adjust the spectral data using the stored correction data, wherein the spectrometer module comprises: at least one electronic circuit module comprising a light sensitive area for detecting incident light of a plurality of wavelengths within a set wavelength interval, wherein detected light of a plurality of wavelengths forms spectral data and the light sensitive area comprises a plurality of light detectors, each of which is arranged to detect light of a selected wavelength, and a plurality of filters for controlling wavelengths of light that are allowed to pass towards respective light detectors, wherein a respective one of the plurality of filters is arranged on top of each of the light detectors, wherein the stored correction data comprises a predetermined characteristic of the at least one electronic circuit module that allows for correcting the wavelength detected by each light detector, wherein the wavelengths detected by the light detectors have a known relationship to the wavelength detected by a reference light detector of the plurality of light detectors and the predetermined characteristic comprises only information of the wavelength detected by the reference light detector. a spectrometer module (to) adapted to acquire spectral information and output spectral data representing the acquired spectral information; a memory storing predetermined correction data for correcting the spectral data detected by the spectrometer module; and a processing unit, which is configured to adjust the spectral data using the stored correction data, wherein the spectrometer module comprises: at least one electronic circuit module comprising a light sensitive area for detecting incident light of a plurality of wavelengths within a set wavelength interval, wherein detected light of a plurality of wavelengths forms spectral data and the light sensitive area comprises a plurality of light detectors, each of which is arranged to detect light of a selected wavelength, and a plurality of filters for controlling wavelengths of light that are allowed to pass towards respective light detectors, wherein a respective one of the plurality of filters is arranged on top of each of the light detectors, a light sensitive area for detecting incident light of a plurality of wavelengths within a set wavelength interval, wherein detected light of a plurality of wavelengths forms spectral data and the light sensitive area comprises a plurality of light detectors, each of which is arranged to detect light of a selected wavelength, and a plurality of filters for controlling wavelengths of light that are allowed to pass towards respective light detectors, wherein a respective one of the plurality of filters is arranged on top of each of the light detectors, wherein the stored correction data comprises a predetermined characteristic of the at least one electronic circuit module that allows for correcting the wavelength detected by each light detector, wherein the wavelengths detected by the light detectors have a known relationship to the wavelength detected by a reference light detector of the plurality of light detectors and the predetermined characteristic comprises only information of the wavelength detected by the reference light detector.