Abstract: A method of modeling a surface of an object using ultrasonic transducers mounted on the surface by: providing a model of the surface comprising a primary set of surface points indicative of the height of the surface, transmitting pulsed waves from a first transducer to one or more second transducers along respective paths along the surface, measuring travel times of the pulsed waves along each path, calculating travel times based on the model of the surface, adjusting the model of the surface in response to any discrepancies between the measured travel times and the calculated travel times. The above steps are repeated until the discrepancies are smaller than a predetermined threshold. The step of calculating the travel times comprises interpolating the primary set of surface points in order to obtain an expanded secondary set of surface points, and the travel times are calculated using the expanded set.

Abstract: A method of modelling a surface (3) of an object (2) using ultrasonic transducers (4, 5) mounted on the surface comprises the steps of: providing a model of the surface, the model comprising a primary set of surface points indicative of the height of the surface, transmitting pulsed waves from a first transducer (4) to one or more second transducers (5), the first transducer and each second transducer defining a respective path along the surface, measuring travel times of the pulsed waves along each path, calculating travel times based on the model of the surface, adjusting the model of the surface in response to any discrepancies between the measured travel times and the calculated travel times, and repeating the steps of transmitting, measuring, calculating and adjusting until the discrepancies are smaller than a predetermined threshold.