System and method for illumination source identification

A light detection module receptive to incident light, the light detection module comprising:

• N optical channels, wherein each optical channel comprises:
• an optical filter with a center wavelength and a bandwidth specific to that channel;
• a detector positioned and operatively configured to produce a time-varying channel current proportional to a time-varying intensity of the incident light reaching the detector after passage through the filter in that channel;
• an amplifier, connected to the detector such that the time-varying channel current is converted to a time-varying channel voltage;
• and
• a channel ADC operating on the time-varying channel voltage to produce a digital voltage data stream for that optical channel at a channel output port;
• a microcontroller having a digital input port connected to each of the channel output ports, the microcontroller being operatively configured to cycle through the channel output ports in turn and, for each optical channel:
• to control an acquisition sequence by setting a sampling rate and a sample duration used by the ADC to provide the digital voltage data stream;
• and
• to make an average normalized optical intensity value characterizing the voltage data stream for that channel available at a digital output port of the microcontroller;
• such that the module provides an output at the digital output port of the microcontroller comprising N data values, characterizing the light incident on the N optical channels of the module.

A light detection system for unmixing light in an incident light mixture comprising light from M artificial light sources, to obtain relative abundances of each of the M artificial light sources;

• the system comprising:
• a linear spectral mixture analysis sub-system with N optical channels exposed to the incident light mixture, each optical channel configured to:
• detect a time-varying light intensity reaching a channel detector after passage through a channel optical bandpass filter;
• sample a time-varying signal corresponding to the time-varying light intensity to provide a first stream of digital data values;
• and
• a flicker spectrum characterization sub-system configured to:
• convert the N time-domain first streams of digital data values into N frequency-domain second streams of digital data values;
• and
• sample the N frequency-domain digital streams of digital data values at H flicker sampling frequencies where H is a positive integer;
• such that an average value and H optical intensity values at H harmonics of a fundamental flicker frequency, are generated for each of the N optical channels and are provided as an output from the flicker spectrum characterization sub-system.