Flexible ultrasound array for measuring a curved object with scattering element

A method for acoustically measuring a curved object, the method comprising:

• providing a flexible sheet with an array of transducers distributed over a sheet surface of the flexible sheet;
• wrapping the flexible sheet at least partially around the curved object such that the array of transducers acoustically contact the curved object;
• using the array of transducers to measure acoustic waves at variable locations around the curved object, wherein spatial coordinates of the variable locations in three dimensional space are dependent on a deformation of the sheet surface wrapping around the curved object;
• and
• determining the spatial coordinates of the acoustic transducers, while the flexible sheet is wrapped around the curved object, based on a set of travel times of the acoustic waves sent through the curved object originating from a common origin,
• wherein the determining the spatial coordinates comprises:
• collecting the set of arrival times into different subsets, wherein each subset of arrival times corresponds to a respective transducer subarray of the array of transducers, spanning a respective subarea of the flexible sheet at respective surface coordinates along the sheet surface;
• determining, based on the respective subset of arrival times for each transducer subarray, of the array of transducers, a respective wave direction at which respective parts of the acoustic waves arrive at the respective subarea originating from the common origin;
• determining a modelled shape of the sheet surface based at least in part on the respective wave direction as a function of the surface coordinates of a respective subarea;
• and
• determining the spatial coordinates of the transducers based on the modelled shape of the sheet surface.

A non-transitory computer-readable medium storing instructions that, when executed by an acoustic system, causes the acoustic system to perform:

• controlling an array of transducers to measure acoustic waves at variable locations around a perimeter of a curved object, wherein spatial coordinates of the variable locations in three dimensional space depend on the perimeter of the curved object;
• determining the spatial coordinates of the transducers based on a set of travel times of the acoustic waves sent through the curved object originating from a common origin;
• and
• generating an image of the object by processing acoustic signals measured from at least a transducer subarray of the array of transducers, wherein the acoustic signals are processed based on the determined spatial coordinates,
• wherein the determining the spatial coordinates comprises:
• collecting the set of arrival times into different subsets, wherein each subset of arrival times corresponds to a respective transducer subarray of the array of transducers spanning a respective subarea of the flexible sheet at respective surface coordinates along the sheet surface;
• determining, based on the respective subset of arrival times for each transducer subarray of the transducers, a respective wave direction at which respective parts of the acoustic waves arrive at the respective subarea originating from the common origin;
• determining a modelled shape of the sheet surface based at least in part on the respective wave direction as function of the surface coordinates of a respective subarea;
• and
• determining the spatial coordinates of the transducers based on the modelled shape of the sheet surface.