Device for eliminating optical noise

A device for eliminating optical noise, the device being configured to receive an optical signal accompanied by the optical noise, the device comprising:

• a first optical filter which transmits light within a wavelength range of the optical signal, so as to have a first output of a filtered signal which includes the optical signal and a first background noise falling within the wavelength range of the optical signal;
• a second optical filter which transmits light having a wavelength falling outside of the wavelength range of the optical signal, so as to have a second output of a second background noise;
• an optical to electrical converter which is coupled to said first optical filter and said second optical filter for receiving respectively the filtered signal and the second background noise, converts the filtered signal into a first electrical signal that has a first voltage positively proportional to illuminance of the filtered signal, and converts the second background noise into a second electrical signal that has a second voltage positively proportional to illuminance of the second background noise;
• and
• an operational unit which is coupled electrically to said optical to electrical converter for receiving the first electrical signal and the second electrical signal therefrom, and performs a mathematical operation on a first product of the first electrical signal and a first parameter and a second product of the second electrical signal and a second parameter, so as to result in a third output signal that has a third voltage positively proportional to illuminance of the optical signal, wherein the first parameter and the second parameter are associated with illuminance of the first background noise and the illuminance of the second background noise.