The method for obtaining an image of a part to be inspected includes the steps of determining, by simulation, the ultrasonic field (s0) generated by the propagation of a wave in a flawless reference part; transmitting an ultrasonic wave toward the part to be inspected; measuring the field (um) returned by the part to be inspected; subtracting from the field (um) returned by the part to be inspected an ultrasonic field (u0) obtained from a previous corresponding measurement on the reference part; calculating a variable related to the topological energy (ET) in the reference part on the basis of the field (s0) determined by simulation and of the field (um−u0) obtained by subtraction; and determining the image of the part to be inspected on the basis of the values for this variable.