Hardware modeling of LED relative brightness

摘要

Via simple electronic circuitry, an analog voltage that tracks the LED light output is produced. This analog voltage is read by an A/D converter to ascertain an approximate relative light output of the LED so that light output compensation can be quickly calculated. A resistor-capacitor circuit is used to approximate the behavior of the LED light output. The output voltage from this circuit is sampled and used along with a sensed ambient temperature to adjust the exposure time of an image capture system.