Abstract: A soft-field tomography system includes a plurality of transducers, one or more excitation drivers, one or more response detectors, and a soft-field reconstruction module. The transducers are configured for positioning proximate a surface of an object to be imaged, and are configured to apply excitations to the surface of the object. The excitation drivers are coupled to the transducers and configured to generate excitation signals to be applied by the transducers. The response detectors are coupled to the transducers and configured to measure a response of the object at the transducers to acquire an Electrical Impedance Tomography (EIT) data set. The soft-field reconstruction module is configured to select a model domain for the EIT data set that represents a predetermined shape, determine a minimally anisotropic error in the model domain, and perform isotropization using the determined minimally anisotropic error to recover a boundary shape and isotropic conductivity.

Abstract: A system and method for soft-field reconstruction are provided. One method includes establishing an initial estimate of a property distribution of an object, using a first reconstruction process to reconstruct an estimate of the actual property distribution and using a second reconstruction process different than the first reconstruction process to further reconstruct the estimate of the actual property distribution. A solution from the first reconstruction process is used as an initial estimate in the second reconstruction process.

Abstract: A soft-field tomography system includes a plurality of transducers configured for positioning at a surface of an object. An excitation driver is configured to generate a precomputed default excitation pattern for the plurality of transducers. A processor stores the precomputed default excitation pattern and a corresponding predicted response for the precomputed excitation pattern. The processor further stores one or more precomputed fault excitation patterns and corresponding predicted response for the fault excitation patterns corresponding to one or more fault conditions of the plurality of transducers. A response measurement device is configured to measure a response at one or more of the transducers to determine if a fault condition exists. If a fault condition exists, the processor at least one of instructs the excitation driver to generate a precomputed fault excitation pattern or uses a predicted response that corresponds to the fault condition for a soft field tomography process.

Abstract: A system and method for transducer placement in soft-field tomography are provided. One system includes a plurality of transducers configured for positioning at a surface of an object in a non-soft-field tomography configuration. The system also includes an interface and a processor communicating with the plurality of transducers via the interface. The processor is configured to perform soft-field sensing using soft-field data acquired by the plurality of transducers.

Abstract: An iteration method for computing a distribution of one or more properties within an object comprises defining a first mesh of the object, applying an excitation to the object, computing a response of the object to the applied excitation, obtaining a reference response of the object corresponding to the applied excitation, computing a distribution of one or more properties of the object, and updating at least a subset of the nodes of the first mesh to form an updated mesh of the object. The distribution of one or more properties of the object is computed using the computed response, the reference response, and the first mesh. The first mesh includes a plurality of nodes and elements. A connectivity relationship of the subset of the nodes in the updated mesh remains the same as in the first mesh.

Abstract: A system and method for determining physiological parameters based on electrical impedance measurements is provided. One method includes obtaining electrical measurement signals acquired from a plurality of transducers coupled to a surface of an object and constructing a system matrix to define one or more relationships between the impedance measurement signals. The method also includes decomposing the system matrix to separate the electrical measurement signals.

Abstract: A system and method for artifact suppression in soft-field tomography are provided. One method includes obtaining an excitation pattern and applying the excitation pattern to an object, wherein the excitation pattern includes a plurality of frequency components. The method also includes measuring a response at one or more of a plurality of transducers coupled to the object and separating the responses among the plurality of frequency components to suppress one or more artifacts.

Abstract: A system and method for transducer placement in soft-field tomography are provided. One system includes a plurality of transducers configured for positioning at a surface of an object in a non-soft-field tomography configuration. The system also includes an interface and a processor communicating with the plurality of transducers via the interface. The processor is configured to perform soft-field sensing using soft-field data acquired by the plurality of transducers.

Abstract: A system and method for soft-field tomography data acquisition are provided. One system includes a plurality of transducers that correspond to a plurality of channels, and an excitation driver coupled to generate excitation signals for the plurality of transducers. The system also includes a single reference excitation source from which excitations are generated and one or more derived excitation sources. The one or more derived excitation sources derive excitations from the single reference excitation source that are applied to each of the plurality of channels. The system further includes a response detector and a reduced bit digitizer in each of the plurality of channels configured to digitize a measured response difference between the measured response at one or more of the transducers and at least one of an excitation of the single reference excitation source or an excitation derived from the single reference excitation source or a separate reference.

Abstract: A system and method for excitation generation in soft-field tomography are provided. One method includes applying a plurality of phase modulated (or phase and amplitude modulated) excitations to a plurality of transducers of a data acquisition system positioned proximate a surface of an object and measuring a response to the applied phase modulated (or phase and amplitude modulated) excitations at the plurality of transducers. The method also includes determining a property of the object based on the measured responses.

Abstract: A system and method for soft-field tomography data acquisition are provided. One system includes a plurality of transducers that correspond to a plurality of channels, and an excitation driver coupled to generate excitation signals for the plurality of transducers. The system also includes a single reference excitation source from which excitations are generated and one or more derived excitation sources. The one or more derived excitation sources derive excitations from the single reference excitation source that are applied to each of the plurality of channels. The system further includes a response detector and a reduced bit digitizer in each of the plurality of channels configured to digitize a measured response difference between the measured response at one or more of the transducers and at least one of an excitation of the single reference excitation source or an excitation derived from the single reference excitation source or a separate reference.

Abstract: An iteration method for computing a distribution of one or more properties within an object comprises defining a first mesh of the object, applying an excitation to the object, computing a response of the object to the applied excitation, obtaining a reference response of the object corresponding to the applied excitation, computing a distribution of one or more properties of the object, and updating at least a subset of the nodes of the first mesh to form an updated mesh of the object. The distribution of one or more properties of the object is computed using the computed response, the reference response, and the first mesh. The first mesh includes a plurality of nodes and elements. A connectivity relationship of the subset of the nodes in the updated mesh remains the same as in the first mesh.

Abstract: A system and method for artifact suppression in soft-field tomography are provided. One method includes obtaining an excitation pattern and applying the excitation pattern to an object, wherein the excitation pattern includes a plurality of frequency components. The method also includes measuring a response at one or more of a plurality of transducers coupled to the object and separating the responses among the plurality of frequency components to suppress one or more artifacts.

Abstract: A soft-field tomography system includes a plurality of transducers configured for positioning at a surface of an object. An excitation driver is configured to generate a precomputed default excitation pattern for the plurality of transducers. A processor stores the precomputed default excitation pattern and a corresponding predicted response for the precomputed excitation pattern. The processor further stores one or more precomputed fault excitation patterns and corresponding predicted response for the fault excitation patterns corresponding to one or more fault conditions of the plurality of transducers. A response measurement device is configured to measure a response at one or more of the transducers to determine if a fault condition exists. If a fault condition exists, the processor at least one of instructs the excitation driver to generate a precomputed fault excitation pattern or uses a predicted response that corresponds to the fault condition for a soft field tomography process.

Abstract: A system and method for determining physiological parameters based on electrical impedance measurements is provided. One method includes obtaining electrical measurement signals acquired from a plurality of transducers coupled to a surface of an object and constructing a system matrix to define one or more relationships between the impedance measurement signals. The method also includes decomposing the system matrix to separate the electrical measurement signals.

Abstract: A system and method for soft-field reconstruction are provided. One method includes establishing an initial estimate of a property distribution of an object, using a first reconstruction process to reconstruct an estimate of the actual property distribution and using a second reconstruction process different than the first reconstruction process to further reconstruct the estimate of the actual property distribution. A solution from the first reconstruction process is used as an initial estimate in the second reconstruction process.

Abstract: A fiberoptic multi-parameter sensing system for monitoring turbomachinery system shaft static and dynamic torques, vibration modes and associated operation status includes a multi-furcated fiber bundle based optical splitter configured to transmit light to a surface of at least one turbomachinery system shaft through a plurality of optical fiber bundles disposed at a plurality of locations in proximity to the surface of the at least one shaft, in which the plurality of locations together are arranged in a substantially axial direction between the ends of the at least one shaft.

Abstract: A fiberoptic multi-parameter sensing system for monitoring turbomachinery system shaft static and dynamic torques, vibration modes and associated operation status includes a multi-furcated fiber bundle based optical splitter configured to transmit light to a surface of at least one turbomachinery system shaft through a plurality of optical fiber bundles disposed at a plurality of locations in proximity to the surface of the at least one shaft, in which the plurality of locations together are arranged in a substantially axial direction between the ends of the at least one shaft.