Abstract: Pipeline wall thickness is measured as a function of position using ultrasound propagation. A series of predictive models is used, which define predictions of the ultrasound response signals as a function of different sets of parameters. The different sets that are determine of position dependent ultrasound speed at different sound frequencies and different spatial resolution. Successive iterative fitting process are executed, each fitting a combination of values of a successive set of parameters to the detected ultrasound response signals according to a respective model, using the values fitted values from the previous fitting process to initialize the next set of parameters for iterative fitting.

Abstract: A method of modelling a surface of an object by using ultrasonic waves transmitted along the surface comprises the steps of: transmitting the ultrasonic waves along paths along the surface, and determining travel times of the ultrasonic waves along the paths. At least some of the ultrasonic waves exhibit an S0 mode and have a frequency-dependent velocity. This velocity (c) is relatively high for frequencies up to a first bending point (BP1), decreasing relatively rapidly for frequencies between the first bending point (BP1) and a second bending point (BP2), and relatively low for frequencies beyond the second bending point (BP2). The ultrasonic waves have a frequency range which lies at or below the first bending point (BP1).

Abstract: A method of producing a temperature model of a surface of an object using ultrasonic transducers comprises the steps of iteratively adjusting a temperature model by using measured travel times of ultrasonic waves and their predictions model-based. The ultrasonic waves used for producing the temperature model are preferably substantially non-dispersive ultrasonic waves. The method may further involve a height model of the surface, which height model is produced using substantially dispersive ultrasonic waves and is corrected by using the temperature model.

Abstract: Pipeline wall thickness is measured as a function of position using ultrasound propagation. A series of predictive models is used, which define predictions of the ultrasound response signals as a function of different sets of parameters. The different sets that are determine of position dependent ultrasound speed at different sound frequencies and different spatial resolution. Successive iterative fitting process are executed, each fitting a combination of values of a successive set of parameters to the detected ultrasound response signals according to a respective model, using the values fitted values from the previous fitting process to initialize the next set of parameters for iterative fitting.

Abstract: A method of modelling a surface of an object by using ultrasonic waves transmitted along the surface comprises the steps of: transmitting the ultrasonic waves along paths along the surface, and determining travel times of the ultrasonic waves along the paths. At least some of the ultrasonic waves exhibit an S0 mode and have a frequency-dependent velocity. This velocity (c) is relatively high for frequencies up to a first bending point (BP1), decreasing relatively rapidly for frequencies between the first bending point (BP1) and a second bending point (BP2), and relatively low for frequencies beyond the second bending point (BP2). The ultrasonic waves have a frequency range which lies at or below the first bending point (BP1).

Abstract: A method of producing a temperature model of a surface of an object using ultrasonic transducers comprises the steps of iteratively adjusting a temperature model by using measured travel times of ultrasonic waves and their predictions model-based. The ultrasonic waves used for producing the temperature model are preferably substantially non-dispersive ultrasonic waves. The method may further involve a height model of the surface, which height model is produced using substantially dispersive ultrasonic waves and is corrected by using the temperature model.