Ultrasound method and device for representing the propagation of ultrasound waves in a guide of linearly variable thickness

A device for the representation, in a frequency-wavenumber frame, of the propagation of an ultrasound wave in a dihedral guide, the device comprising:

• ultrasound emitters referenced by Ej with j an integer varying between 1 and N, N a strictly positive integer;
• ultrasound receivers referenced by Ri with i an integer varying between 1 and M, M a strictly positive integer;
• and
• means for processing and outputting the signal received by the receivers, originating from the emitters, wherein
• the receivers are disposed spatially over a first segment of a straight line according to a regular pitch A that is a scalar length value,
• the processing means comprise means for calculating a modified discrete spatial Fourier transform, for a spatial integration variable x, centered in the middle of said first segment and traversing the receivers in the direction of increasing x, and for a spatially-varying wave vector k(x) equal to a product k.P(x),
• k is a wavenumber coefficient which is constant in x and lies between wave vector values 0 and 2*Pi/A,
• 2*Pi/A is a wave vector value defined by diving 2*Pi by the regular pitch A,
• P(x) is a polynomial in x, of coefficient of degree 0 in x equal to 1 and of coefficient C of degree 1 in x such that C.A lies between − 1/10 and + 1/10, and
• C.A is a scalar value defined by multiplying the coefficient C of degree 1 in x by the regular pitch A.