A method for detecting an active pixel in a sensor having a plurality of addressable pixels, comprising detecting a trigger event that causes a pixel to go active and setting a corresponding resettable latch from an initial unset logic state to a set logic state and establishing a time window during which another pixel which becomes active is assumed to originate from the same trigger event. For all pixels that become active within the time window a corresponding analog value of the pixel is sampled and held in response to a logic signal indicative of another pixel currently being active, and an incident time of the pixel going active is established. Each of the latches in the segment is sparsely read so as successively to identify latches which are in the set logic state each corresponding to an active pixel having a known address in the sensor segment. The known address of each active pixel is associated with the incident time of the pixel going active and the respective sampled and held analog value. The process is repeated respect of successive active pixels, after which the latches are reset.