Patent ID: 8045017

Claim:
A method of detecting a frequency of a pulsating light connected to an AC power supply, comprising: simultaneously using a first dedicated pixel to collect a first sample of an intensity of the pulsating light at a first sampling frequency that is an integer multiple of a first known pulsating light frequency and a second dedicated pixel to collect a second sample of the intensity of the pulsating light at a second sampling frequency that is an integer multiple of a second known pulsating light frequency; determining, in the time domain, whether the intensity in the first sample is time-varying and whether the intensity in the second sample is time-varying; concluding, if the intensity of the first sample is not time-varying and the intensity of the second sample is time varying, that the frequency of the pulsating light is an integer multiple of the first sampling frequency; and concluding, if the intensity of the second sample is not time-varying and the intensity of the first sample is time varying, that the frequency of the pulsating light is an integer multiple of the second sampling frequency.