Abstract: A method for imaging an object is provided. The method includes acquiring tomographic image data of the object at a plurality of frequencies, generating a composite image of the object at each of the plurality of frequencies using the acquired tomographic image data, determining a scaling factor for a first material at each of the plurality of frequencies, determining a scaling factor for a second material at each of the plurality of frequencies, and decomposing the composite images into a first discrete image and a second discrete image using the determined scaling factors, wherein the first discrete image contains any region of the object composed of the first material and the second discrete image contains any region of the object composed of the second material.

Abstract: A multi-frequency eddy current (MFEC) inspection system is provided for inspection of case hardening depth on a part. The MFEC inspection system comprises a generator configured to generate one or more multi-frequency excitation signals and an eddy current probe configured to be disposed at one side of the part. The eddy current probe comprises one or more drivers and one or more pickup sensors. The one or more drivers are configured to receive the one or more multi-frequency excitation signals to induce eddy currents in the part. The one or more pickup sensors are configured to detect the induced eddy currents within a local area of the part to generate one or more multi-frequency response signals. The MFEC system further comprises a processor configured to receive the one or more multi-frequency response signals for processing to determine a case hardening depth of the local area of the part. A pulse eddy current inspection system and an eddy current inspection method are also presented.

Abstract: A method of inspecting a test part is provided. The method includes positioning a coil on a surface of the test part and exciting the coil at a resonance frequency. The method also includes determining at least one of a resonance frequency shift and a quality factor of the coil and estimating an electrical conductivity of the test part based on at least one of the resonance frequency shift and the quality factor of the coil. The method further includes obtaining depth profile of residual stress using conductivity measurements at various resonance frequencies.

Abstract: A method of inspecting a test part is provided. The method includes positioning an eddy current probe on a surface of the test part and scanning the test part using the eddy current probe to generate a first signal corresponding to a no lift-off condition of the test part. The method further includes positioning the eddy current probe at a pre-determined distance from the surface of the test part and scanning the test part using the eddy current probe positioned at the pre-determined distance from the test part to generate a second signal corresponding to a lift-off condition of the test part. The method also includes processing the first and second signals to estimate an electrical conductivity of the test part.

Abstract: A method of inspecting a test part is provided. The method includes positioning a coil on a surface of the test part and exciting the coil at a resonance frequency. The method also includes determining at least one of a resonance frequency shift and a quality factor of the coil and estimating an electrical conductivity of the test part based on at least one of the resonance frequency shift and the quality factor of the coil. The method further includes obtaining depth profile of residual stress using conductivity measurements at various resonance frequencies.

Abstract: A method of inspecting a test part is provided. The method includes positioning an eddy current probe on a surface of the test part and scanning the test part using the eddy current probe to generate a first signal corresponding to a no lift-off condition of the test part. The method further includes positioning the eddy current probe at a pre-determined distance from the surface of the test part and scanning the test part using the eddy current probe positioned at the pre-determined distance from the test part to generate a second signal corresponding to a lift-off condition of the test part. The method also includes processing the first and second signals to estimate an electrical conductivity of the test part.

Abstract: A method for inspecting an object is provided. The method includes applying a pulsed excitation signal to the object and detecting a transient response signal to the pulsed excitation signal. The method also includes convolving the transient response signal with a plurality of orthogonal functions to generate a plurality of orthogonal components.

Abstract: A method for inspecting an object is provided. The method includes applying a pulsed excitation signal to the object and detecting a transient response signal to the pulsed excitation signal. The method also includes convolving the transient response signal with a plurality of orthogonal functions to generate a plurality of orthogonal components.

Abstract: An eddy current (EC) probe for inspecting a component is provided. The EC probe includes a tangential drive coil configured to generate a probing field for inducing eddy currents in the component, where a portion of the eddy currents are aligned parallel to an edge of the component. An axis of the tangential drive coil is aligned parallel to a surface of the component. The EC probe further includes a pair of sense coils, where an axis of the sense coils is aligned perpendicular to the surface of the component. The sense coils are configured to sense the portion of the eddy currents aligned parallel to the edge of the component.

Abstract: An omnidirectional eddy current (EC) probe includes at least one EC channel having a first and a second sense coil that are offset in a first (x) and a second (y) direction and overlap in at least one of the directions (x,y). At least one drive coil is configured to generate a probing field for the EC channel in a vicinity of the sense coils. An omnidirectional EC inspection system includes an omnidirectional EC array probe (ECAP) that includes a number of EC channels and drive coils. Each EC channel includes first and second sense coils with opposite polarities. The drive coils have alternating polarities. Electrical connections perform differential sensing for respective EC channels. Corrective drive coils are disposed at respective ends of the EC channels and generate probing fields. An eddy current instrument is connected to the omnidirectional ECAP and receives differential sensing signals from the EC channels.

Abstract: In some aspects, the present invention provides a method for estimating at least one measurement/object property of a metal object. The method includes generating a time-varying eddy current in a wall of the metal object utilizing a pulsed-signal transmitter. The method further includes measuring the time-varying eddy current, fitting the time-varying measured eddy current to a parameterized polynomial, and interpreting the parameterized polynomial to determine one or more measurement/object properties of the metal object.

Abstract: A pulsed eddy current sensor probe includes a sensor array board. A number of sensors are arranged on the sensor array board and are operable to sense and generate output signals from the transient electromagnetic flux in a part being inspected. Each of the sensors has a differential output with a positive and a negative output. At least one drive coil is disposed adjacent to the sensors and is operable to transmit transient electromagnetic flux into the part. A first and a second multiplexer are arranged on the sensor array board and are operable to switch between the sensors. The first and second multiplexers are connected to the positive and negative outputs of the sensors, respectively.

Abstract: A pulsed eddy current sensor probe includes a sensor array board. A number of sensors are arranged on the sensor array board and are operable to sense and generate output signals from the transient electromagnetic flux in a part being inspected. Each of the sensors has a differential output with a positive and a negative output. At least one drive coil is disposed adjacent to the sensors and is operable to transmit transient electromagnetic flux into the part. A first and a second multiplexer are arranged on the sensor array board and are operable to switch between the sensors. The first and second multiplexers are connected to the positive and negative outputs of the sensors, respectively.

Abstract: A pulsed eddy current two-dimensional sensor array probe for electrically conducting component inspection includes a drive coil disposed adjacent to a structure under inspection, a pulse generator connected to the drive coil and operable to energize in a pulsed manner the drive coil to transmit transient electromagnetic flux into the structure under inspection, and an array of sensors arranged in a two-dimensional array and substantially surrounded by the drive coil and operable to sense and generate output signals from the transient electromagnetic flux in the structure under inspection.

Abstract: A method for in-situ eddy current inspection of at least one coated component includes applying a drive pulse at a measurement position on an outer surface of the coated component, while the coated component is installed in an operational environment of the coated component. The coated component includes a base metal and a coating disposed on the base metal. The method further includes receiving a response signal from the coated component, comparing the response signal with a reference signal to obtain a compared signal, analyzing the compared signal for crack detection, and determining whether a crack near the measurement position has penetrated into the base metal, if the presence of the crack in the coating is indicated.

Abstract: A method for in-situ eddy current inspection of at least one coated component includes applying a drive pulse at a measurement position on an outer surface of the coated component, while the coated component is installed in an operational environment of the coated component. The coated component includes a base metal and a coating disposed on the base metal. The method further includes receiving a response signal from the coated component, comparing the response signal with a reference signal to obtain a compared signal, analyzing the compared signal for crack detection, and determining whether a crack near the measurement position has penetrated into the base metal, if the presence of the crack in the coating is indicated.

Abstract: A pulsed eddy current two-dimensional sensor array probe for electrically conducting component inspection includes a drive coil disposed adjacent to a structure under inspection, a pulse generator connected to the drive coil and operable to energize in a pulsed manner the drive coil to transmit transient electromagnetic flux into the structure under inspection, and an array of sensors arranged in a two-dimensional array and substantially surrounded by the drive coil and operable to sense and generate output signals from the transient electromagnetic flux in the structure under inspection.