Abstract: A method of determining the time delay between echoes of an ultrasound pulse emitted by an ultrasound inspection device into an object, the method including: with the ultrasound probe in engagement with a front-wall feature of the object such that the ultrasound inspection device's ultrasound axis is arranged at an angle relative to the nominal surface normal of the front-wall feature, taking an ultrasound measurement which includes the ultrasound inspection device emitting an ultrasound pulse and recording echoes thereof; and determining the time delay between echoes of the pulse via a time delay determination process which adjusts the time delay calculation based on the angle of the ultrasound inspection device's ultrasound axis with respect to the nominal surface normal of the front-wall feature.

Abstract: A method of calibrating an ultrasound probe having a coupling element for engaging the surface of an object to be inspected, in which the ultrasound probe and a calibration artefact are provided on a positioning apparatus having at least one axis about which the relative orientation of the ultrasound probe and calibration artefact can be changed, the method including, in any suitable order: i) for a plurality of different relative orientations between the ultrasound probe and the calibration artefact about the at least one axis, measuring the signal received by the ultrasound probe; and ii) from the measurements, determining at least one calibration parameter which is indicative of at least one axis of optimum signal of the ultrasound probe, and recording the at least one calibration parameter for subsequent use.