Autoreferenced and self-adjusted spectral sensor

A spectral sensor, comprising:

• an optical head comprising:
• a light source configured to produce input light,
• an optical window directly above the light source and through which the input light is directed towards a sample and first diffuse reflected light is received from the sample in a sample measurement mode,
• a moveable reference flag moveable between a first position beneath the optical window and within a light path of the input light in a reference measurement mode and a second position away from the light path of the input light in the sample measurement mode, wherein the moveable reference flag is coupled to receive the input light and diffuse reflect the input light to produce second diffuse reflected light in the reference measurement mode, and
• an actuator configured to move the moveable reference flag between the first position and the second position;
• and
• a core sensor module comprising:
• an optical core module configured to receive the first diffuse reflected light from the sample in the sample measurement mode and the second diffuse reflected light from the moveable reference flag in the reference measurement mode, wherein the optical core module comprises:
• a light modulator configured to produce first modulated light based on the first diffuse reflected light and second modulated light based on the second diffuse reflected light, and
• a detector configured to produce a first output signal based on the first modulated light and a second output signal based on the second modulated light, and
• a processor configured to obtain a sample power spectral density (PSD) based on the first output signal and a reference PSD based on the second output signal, wherein the processor is further configured to correct the sample PSD in both intensity and wavelength based on at least the reference PSD to produce a sample spectrum.