Properties of a medium, such as its particle size distribution, are characterized using a measurement cell containing a medium between walls of the cell, with ultrasound transducers on opposite walls. Ultrasound is transmitted from the ultrasound transducers on both sides and transmission and reflection responses are detected. An ultrasound frequency dependent ratio of a Fourier transform value of a product of signals obtained from transmission responses in opposite directions and a Fourier transform value of a product of signals obtained from reflections at the transducers is computed. Preferably, the first received reflected and transmitted pulses in response to pulse excitation are used to compute the ratio. Ultrasound frequency dependent ultrasound speed and/or attenuation data of ultrasound in the medium are computed as a function of the ultrasound frequency from the ratio. This eliminates the effect of the walls.

Properties of a medium, such as its particle size distribution, are characterized using a measurement cell containing a medium between walls of the cell, with ultrasound transducers on opposite walls. Ultrasound is transmitted from the ultrasound transducers on both sides and transmission and reflection responses are detected. An ultrasound frequency dependent ratio of a Fourier transform value of a product of signals obtained from transmission responses in opposite directions and a Fourier transform value of a product of signals obtained from reflections at the transducers is computed. Preferably, the first received reflected and transmitted pulses in response to pulse excitation are used to compute the ratio. Ultrasound frequency dependent ultrasound speed and/or attenuation data of ultrasound in the medium are computed as a function of the ultrasound frequency from the ratio. This eliminates the effect of the walls.

A method and system are described for examining the interior material of an object from a surface of an object, using ultrasound having a frequency of at least 100 kHz. The method comprises the step of transmitting at least a first ultrasound signal by a first ultrasound transmitter of a first number of ultrasound transmitters to the interior material of the object for forming a first image in order to determine, according for example to the principle of inverse wave field extrapolation, where in the interior material of the object reflections and/or diffractions occur. Reflections and/or diffractions of the first ultrasound signal from the interior material of the object are received using a second number of ultrasound receivers which are acoustically coupled to the surface of the object at positions which are distributed in at least one dimension of the surface of the object. With each of the second number of ultrasound receivers, a receiving signal is generated from the received reflections and/or diffractions of the first ultrasound signal from the interior material of the object, and each of the receiving signals generated by one of the ultrasound receivers is processed separately into a separate dataset. The separate datasets of all the ultrasound receivers are combined to the first image.

A method and system are described for examining the interior material of an object from a surface of an object, using ultrasound having a frequency of at least 100 kHz. The method comprises the step of transmitting at least a first ultrasound signal by a first ultrasound transmitter of a first number of ultrasound transmitters to the interior material of the object for forming a first image in order to determine, according for example to the principle of inverse wave field extrapolation, where in the interior material of the object reflections and/or diffractions occur. Reflections and/or diffractions of the first ultrasound signal from the interior material of the object are received using a second number of ultrasound receivers which are acoustically coupled to the surface of the object at positions which are distributed in at least one dimension of the surface of the object. With each of the second number of ultrasound receivers, a receiving signal is generated from the received reflections and/or diffractions of the first ultrasound signal from the interior material of the object, and each of the receiving signals generated by one of the ultrasound receivers is processed separately into a separate dataset. The separate datasets of all the ultrasound receivers are combined to the first image.

A method and system are described for examining the interior material of an object from a surface of an object, using ultrasound having a frequency of at least 100 kHz. The method comprises the step of transmitting at least a first ultrasound signal by a first ultrasound transmitter of a first number of ultrasound transmitters to the interior material of the object for forming a first image in order to determine, according for example to the principle of inverse wave field extrapolation, where in the interior material of the object reflections and/or diffractions occur. Reflections and/or diffractions of the first ultrasound signal from the interior material of the object are received using a second number of ultrasound receivers which are acoustically coupled to the surface of the object at positions which are distributed in at least one dimension of the surface of the object. With each of the second number of ultrasound receivers, a receiving signal is generated from the received reflections and/or diffractions of the first ultrasound signal from the interior material of the object, and each of the receiving signals generated by one of the ultrasound receivers is processed separately into a separate dataset. The separate datasets of all the ultrasound receivers are combined to the first image.

A method and system are described for examining the interior material of an object from a surface of an object, using ultrasound having a frequency of at least 100 kHz. The method comprises the step of transmitting at least a first ultrasound signal by a first ultrasound transmitter of a first number of ultrasound transmitters to the interior material of the object for forming a first image in order to determine, according for example to the principle of inverse wave field extrapolation, where in the interior material of the object reflections and/or diffractions occur. Reflections and/or diffractions of the first ultrasound signal from the interior material of the object are received using a second number of ultrasound receivers which are acoustically coupled to the surface of the object at positions which are distributed in at least one dimension of the surface of the object. With each of the second number of ultrasound receivers, a receiving signal is generated from the received reflections and/or diffractions of the first ultrasound signal from the interior material of the object, and each of the receiving signals generated by one of the ultrasound receivers is processed separately into a separate dataset. The separate datasets of all the ultrasound receivers are combined to the first image.

The present disclosure provides a high-precision ultrasonic imaging method for an internal defect of a complex-shaped component based on a search-vector imaging condition. Based on full waveform inversion, the search-vector imaging condition is constructed, and a first-order derivative vector is combined with an approximate Hessian matrix for correction so that a high-quality image of a defect in a complex sound velocity model can be obtained. The high-precision ultrasonic imaging method is suitable for defect testing on complex surface components. The imaging condition used for the imaging method of the present disclosure does not involve an assumption on a wave field and is stricter than a traditional imaging condition theory, thereby ensuring high precision of the inventive method. Moreover, the imaging method of the present disclosure can highlight a defect in an entire measurement area, which is very convenient for locating a defect in a large-size measurement structure.

The present disclosure provides a high-precision ultrasonic imaging method for an internal defect of a complex-shaped component based on a search-vector imaging condition. Based on full waveform inversion, the search-vector imaging condition is constructed, and a first-order derivative vector is combined with an approximate Hessian matrix for correction so that a high-quality image of a defect in a complex sound velocity model can be obtained. The high-precision ultrasonic imaging method is suitable for defect testing on complex surface components. The imaging condition used for the imaging method of the present disclosure does not involve an assumption on a wave field and is stricter than a traditional imaging condition theory, thereby ensuring high precision of the inventive method. Moreover, the imaging method of the present disclosure can highlight a defect in an entire measurement area, which is very convenient for locating a defect in a large-size measurement structure.

A method and system are described for examining the interior material of an object from a surface of an object using ultrasound having a frequency of at least 100 kHz. The method comprises the step of transmitting at least a first ultrasound signal by a first ultrasound transmitter of a first number of ultrasound transmitters to the interior material of the object for forming a first image in order to determine, according for example to the principle of inverse wave field extrapolation, where in the interior material of the object reflections and/or diffractions occur. Reflections and/or diffractions of the first ultrasound signal from the interior material of the object are received using a second number of ultrasound receivers which are acoustically coupled to the surface of the object at positions which are distributed in at least one dimension of the surface of the object. With each of the second number of ultrasound receivers, a receiving signal is generated from the received reflections and/or diffractions of the first ultrasound signal from the interior material of the object, and each of the receiving signals generated by one of the ultrasound receivers is processed separately into a separate dataset. The separate datasets of all the ultrasound receivers are combined to the first image.

A method and system are described for examining the interior material of an object from a surface of an object using ultrasound having a frequency of at least 100 kHz. The method comprises the step of transmitting at least a first ultrasound signal by a first ultrasound transmitter of a first number of ultrasound transmitters to the interior material of the object for forming a first image in order to determine, according for example to the principle of inverse wave field extrapolation, where in the interior material of the object reflections and/or diffractions occur. Reflections and/or diffractions of the first ultrasound signal from the interior material of the object are received using a second number of ultrasound receivers which are acoustically coupled to the surface of the object at positions which are distributed in at least one dimension of the surface of the object. With each of the second number of ultrasound receivers, a receiving signal is generated from the received reflections and/or diffractions of the first ultrasound signal from the interior material of the object, and each of the receiving signals generated by one of the ultrasound receivers is processed separately into a separate dataset. The separate datasets of all the ultrasound receivers are combined to the first image.