The present invention relates to a method for measuring a time delay between two output signals measured by two adjacent optical sensors, the time delay resulting from a movement of an object moving in a given direction. The method comprises the steps: carrying out a spatial filtering of the signals Ph.sub.1 and Ph.sub.2 delivered by a first and a second optical sensor; calculating a first order derivative and carrying out a temporal low-pass filtering of the signals; calculating the second order derivative of the signals; measuring the delay between the signals; and is characterized in that the step of measuring the delay is a feedback loop based on an estimated delay between the temporally filtered signals. Device and set of devices for measuring the angular velocity of a luminance transition zone and steering aid system for fixation and tracking a target comprising at least one such luminance transition zone.