Detecting ambient light incident on a display includes: detecting incident light at a first photosensor; producing, at the first photosensor, a first measurement signal in response to detecting the incident light at the first photosensor; transmitting the first measurement signal to blink detection circuitry; deriving, at the blink detection circuitry, a blink rate signal from the first measurement signal, in which the blink rate signal is indicative of both an on-period during which light is emitted by a display and an off-period during which light is not emitted by the display; transmitting the blink rate signal to a second photosensor; and detecting incident light at the second photosensor during the off-period of the blink rate signal.