Acoustic holography process and apparatus using a space-limited ultrasonic beam

Claim 1

A method for the acoustic holography of an area to be inspected in an object, and for identifying faults which may exist therein, wherein said method comprises: insonifying the area to be inspected by means of an ultrasonic transmitter producing a space-limited ultrasonic beam, displacing said transmitter so as to successively insonify M areas, in a manner which insonifies the entire area to be inspected; detecting any ultrasonic signals coming from the successively insonified areas and producing electrical signals in response to the ultrasonic beam, by means of several ultrasonic receivers having reciprocal spacings; determining the characteristic, by comparison to the values of a reference beam similar to said ultrasonic beam, values of the detected ultrasonic signals; and reconstructing the area to be inspected by means of said characteristic values wherein said reconstruction method comprises: forming a main image of the fault and any possible secondary reflected images of said fault, thereof due to the said spacings, and providing a number of receivers which is predetermined in such a manner such that the distance between each secondary image and the main image exceeds the width of the areas insonified by said transmitter; and carrying out said reconstruction only in the insonified areas which have provided an ultrasonic signal, thereby eliminating any secondary images which may occur from the reconstruction of the area inspected.

Claim 2

A method for the acoustic holography of an area to be inspected in an object, and for identifying faults which may exist therein, wherein said method comprises: insonifying the area to be inspected by means of an ultrasonic transmitter producing a space-limited ultrasonic beam, displacing said transmitter so as to successively insonify M areas, in a manner which insonifies the entire area to be inspected; detecting any ultrasonic signals coming from the successively insonified areas and producing electrical signals in response to the ultrasonic beam, by means of several ultrasonic receivers having reciprocal spacings; determining the characteristic, by comparison to the values of a reference beam similar to said ultrasonic beam, values of the detected ultrasonic signals; and reconstructing the area to be inspected by means of said characteristic values wherein said reconstruction method comprises: forming a main image of the fault and any possible secondary reflected images of said fault, thereof due to the said spacings, and providing a number of receivers which is predetermined in such a manner such that the distance between each secondary image and the main image exceeds the width of the areas insonified by said transmitter; and carrying out said reconstruction only in the insonified areas which have provided an ultrasonic signal, thereby eliminating any secondary images which may occur from the reconstruction of the area inspected.

Claim 4

An apparatus for the acoustic holographic inspection for faults of an area in an object, comprising: an ultrasonic transmitter able to produce a space-limited ultrasonic beam and which serves to insonify the area to be inspected; means for displacement of said transmitter enabling said transmitter to successively insonify M areas in such a manner so as to cover the area inspected; a plurality of ultrasonic receivers having a spacing S between each of said receivers to detect any ultrasonic signals coming from said successively insonified areas in response to said ultrasonic beam; and means for processing the detected ultrasonic waves and for producing electrical signals indicative of said ultrasonic waves for determining the characteristic values of said indicative signals and for effecting a reconstruction of said area to be inspected with the aid of said characteristic values, wherein said reconstruction incorporates a main image of any faults that might exist in said area along with any possible secondary images of said faults, due to the said spacings; with the number of said receivers being predetermined in such a manner so that the distance between each secondary image produced and the main image produced exceeds the width of the areas insonified by said transmitter, and wherein said processing means serves to function in the reconstruction process only in the insonified areas which have given rise to an ultrasonic signal thereby eliminating any possible secondary images from the reconstruction of said area under inspection.

Claim 5

An apparatus for the acoustic holographic inspection for faults of an area in an object, comprising: an ultrasonic transmitter able to produce a space-limited ultrasonic beam and which serves to insonify the area to be inspected; means for displacement of said transmitter enabling said transmitter to successively insonify M areas in such a manner so as to cover the area inspected; a plurality of ultrasonic receivers having a spacing S between each of said receivers to detect any ultrasonic signals coming from said successively insonified areas in response to said ultrasonic beam; and means for processing the detected ultrasonic waves and for producing electrical signals indicative of said ultrasonic waves for determining the characteristic values of said indicative signals and for effecting a reconstruction of said area to be inspected with the aid of said characteristic values, wherein said reconstruction incorporates a main image of any faults that might exist in said area along with any possible secondary images of said faults, due to the said spacings; with the number of said receivers being predetermined in such a manner so that the distance between each secondary image produced and the main image produced exceeds the width of the areas insonified by said transmitter, and wherein said processing means serves to function in the reconstruction process only in the insonified areas which have given rise to an ultrasonic signal thereby eliminating any possible secondary images from the reconstruction of said area under inspection.