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, a detector, and an amplifier, and each optical channel having an output port;
• an N×1 switch having N input ports and a single output port, wherein each input port is connected to a corresponding one and only one output port of each of said N optical channels to receive a corresponding amplified detector output corresponding to a filtered optical intensity incident on the detector, and wherein the switch is operatively configured to sequentially cycle between channels, to connect each of the amplified detector outputs in turn to the output port of the switch;
• an analog-to-digital converter (ADC) connected to the output port of the N×1 switch, and operatively configured to sample a time dependent optical intensity signal input to the ADC from the switch, and generate a corresponding time dependent digital signal output from the ADC;
• and
• a microcontroller, connected to the N×1 switch and the ADC, and operatively configured to:
• control an acquisition sequence by setting a sampling rate and a sample duration used by the ADC to provide a digital voltage data stream from each channel in turn;
• and
• make at least an average optical intensity value characterizing the voltage data stream available from each optical channel in turn 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;
• wherein the microcontroller is further operatively configured, when cycling through the channel output ports in turn, to, for each channel:
• compute an estimated flicker spectrum from the digital voltage data stream provided by the ADC for that channel;
• sample the estimated flicker spectrum for that channel at DC and at H select flicker sampling frequencies where H is an integer greater than 0;
• and
• make said H values of the estimated flicker spectrum, available at the digital output port of the microcontroller for each channel;
• such that the output provided by the module at the digital output port of the microcontroller comprises N*(1+H) data values, characterizing the light incident on the module.