Abstract: A ranging device includes an array of photon detection devices that receive an optical signal reflected by an object in an image scene and first and second logic devices to respectively combine the outputs of first and second pluralities of the photon detection devices. First and second counter circuits are respectively coupled an output of the first and second logic devices and generate first and second count values respectively by counting the photon detection events generated by the first and second pluralities of photon detection devices. A range estimation circuit estimates the range of the object by estimating the timing of one or more pulses of said optical signal based on the first and second count values.