Incident light from a light source, such as a light bulb or other incandescent source, an unfiltered light-emitting diode, a filtered light bulb or other incandescent source, a filtered light-emitting diode, an unfiltered diode laser, a highly filtered light bulb or incandescent light source, a highly filtered light-emitting diode, or a filtered diode laser, is pulsed or otherwise modulated.