Abstract: The invention provides for improved signal to noise ratios in evaluation techniques. This is done by acquiring a signal, processing it to obtain a complex form thereof, obtaining a filtering factor from the complex form and processing the acquired signal with the filtering factor. The signal may be areturned ultrasonic, radar or sonar signal which may be reflected from a suitably sharp pulse. In particular, the invention may he used to evaluate articles to detect defects therein. In a preferred form, the complex form is filtered with a number of complex filters and the phases of the complex filtered signals determined. These phases are then used to provide the filtering factor.

Abstract: The invention provides for improved signal to noise ratios in evaluation techniques. This is done by acquiring a signal, processing it to obtain a complex form thereof, obtaining a filtering factor from the complex form and processing the acquired signal with the filtering factor. The signal may be areturned ultrasonic, radar or sonar signal which may be reflected from a suitably sharp pulse. In particular, the invention may be used to evaluate articles to detect defects therein. In a preferred form, the complex form is filtered with a number of compelx filters and the phases of the complex filtered signals determined. These phases are then used to provide the filtering factor.

Abstract: There is provided an inspection device and method for inspecting a pump having a casing defining an internal surface and a plurality of radially spaced diffuser vanes arranged within the casing. The inspection device includes an image providing apparatus for providing a remote picture of surfaces of the vanes and the internal surface of the casing, and a maneuverable carrier apparatus for carrying the image providing apparatus, which is sufficiently manoeuvrable to pass into a space defined between adjacent diffuser vanes and beyond.