Abstract: Measuring in a first semiconductor crystal two anode channels and two cathode channels and measuring in a second semiconductor crystal one anode channel and one cathode channel; responsive to an energy of a sum of the two anode channels being within an energy window and an energy of the one anode channel being within the energy window: separating the two anode channels and the two cathode channels into combinations of anode-cathode channel pairs; for each of the anode-cathode channel pairs, determining a respective direction difference angle, each respective direction difference angle being determined via use of the one anode channel and one cathode channel; determining a determined one of the direction difference angles that has a smallest value; and setting as an initial interaction position of a photon a selected one of the anode-cathode channel pairs that corresponds to the determined direction difference angle. Additional embodiments are disclosed.

Abstract: Aspects of the subject disclosure may include, for example, measuring in a first semiconductor crystal two anode channels and two cathode channels and measuring in a second semiconductor crystal one anode channel and one cathode channel; determining whether an energy of a sum of the two anode channels is within an energy window; determining whether an energy of the one anode channel is within the energy window; responsive to the energy of the sum of the two anode channels being within the energy window and the energy of the one anode channel being within the energy window: separating the two anode channels and the two cathode channels into combinations of anode-cathode channel pairs; for each of the anode-cathode channel pairs, determining a respective direction difference angle, each respective direction difference angle being determined via use of the one anode channel and one cathode channel; determining from among the direction difference angles a determined one of the direction difference angles that has

Abstract: A method for providing an image from a device with a plurality of sensors and a plurality of time to digital converters (TDC) is provided. Data signals are generated by some of the plurality of sensors, wherein each sensor of the plurality of sensors provides output in parallel to more than one TDC of the plurality of TDCs and wherein each TDC of the plurality of TDCs receives in parallel input from more than one sensor of the plurality of sensors and where a binary matrix indicates which sensors are connected to which TDC. The data signals are transmitted from the sensors to the TDCs. TDC signals are generated from the data signals. Group testing is used to decode the TDC signals based on the binary matrix.

Abstract: Compressed sensing (CS) estimation approaches rely on a priori sparsity to significantly reduce the number of samples needed to provide high sampling fidelity, relative to the normal Shannon-Nyquist limit. Accordingly, CS approaches are of considerable interest for detector multiplexing in applications which have inherently sparse signals (e.g., the two correlated photon detection events in PET imaging). However, CS approaches also tend to fare poorly in the presence of noise, which has limited their applicability in practice. In this work, we show that CS estimation can be used to provide an estimate of the support of an image. This estimated support is then used as a constraint for maximum likelihood image reconstruction. This approach has robust noise performance and provides high reconstruction fidelity.

Abstract: A method for providing an image from a device with a plurality of sensors and a plurality of time to digital converters (TDC) is provided. Data signals are generated by some of the plurality of sensors, wherein each sensor of the plurality of sensors provides output in parallel to more than one TDC of the plurality of TDCs and wherein each TDC of the plurality of TDCs receives in parallel input from more than one sensor of the plurality of sensors and where a binary matrix indicates which sensors are connected to which TDC. The data signals are transmitted from the sensors to the TDCs. TDC signals are generated from the data signals. Group testing is used to decode the TDC signals based on the binary matrix.

Abstract: Compressed sensing (CS) estimation approaches rely on a priori sparsity to significantly reduce the number of samples needed to provide high sampling fidelity, relative to the normal Shannon-Nyquist limit. Accordingly, CS approaches are of considerable interest for detector multiplexing in applications which have inherently sparse signals (e.g., the two correlated photon detection events in PET imaging). However, CS approaches also tend to fare poorly in the presence of noise, which has limited their applicability in practice. In this work, we show that CS estimation can be used to provide an estimate of the support of an image. This estimated support is then used as a constraint for maximum likelihood image reconstruction. This approach has robust noise performance and provides high reconstruction fidelity.

Abstract: Methods and systems for producing an image. Measurement data is obtained for a coincidence photon event, and a line projector function is generated based on the obtained measurement data. Additional measurement data is obtained for a single photon event, and a cone-surface projector function is generated based on the additional measurement data. An image is reconstructed using the generated line projector function and the generated cone-surface projector function. In another example method for producing an image, a measurement is obtained, and a projector function is generated using the obtained measurement. The generated projector function is modified based on an a priori image. An image is reconstructed using the modified projector function.

Abstract: Methods and systems for producing an image. A measurement is obtained, and a projector function is generated using the obtained measurement. The generated projector function is modified based on an a priori image. An image is reconstructed using the modified projector function.

Abstract: Methods and systems for determining a location of a photon event for an imaging system including a plurality of 3-D detectors. For one of the photons in the photon pair, an interaction in a first 3-D detector is detected. For the other of the photons in the photon pair, at least two interactions in a second 3-D detector are detected. A cone-surface projector function is produced based on the at least two interaction locations in the second 3-D detector. A projector function is produced based on the produced cone-surface projector function, the detected interaction in the first 3-D detector, and the at least two detected interactions in the second 3-D detector.

Abstract: Methods and systems for producing an image. A measurement is obtained, and a projector function is generated using the obtained measurement. The generated projector function is modified based on an a priori image. An image is reconstructed using the modified projector function.

Abstract: Methods and systems for determining a location of a photon event for an imaging system including a plurality of 3-D detectors. For one of the photons in the photon pair, an interaction in a first 3-D detector is detected. For the other of the photons in the photon pair, at least two interactions in a second 3-D detector are detected. A cone-surface projector function is produced based on the at least two interaction locations in the second 3-D detector. A projector function is produced based on the produced cone-surface projector function, the detected interaction in the first 3-D detector, and the at least two detected interactions in the second 3-D detector.

Abstract: Methods and systems for producing an image. Measurement data is obtained for a coincidence photon event, and a line projector function is generated based on the obtained measurement data. Additional measurement data is obtained for a single photon event, and a cone-surface projector function is generated based on the additional measurement data. An image is reconstructed using the generated line projector function and the generated cone-surface projector function. In another example method for producing an image, a measurement is obtained, and a projector function is generated using the obtained measurement. The generated projector function is modified based on an a priori image. An image is reconstructed using the modified projector function.

Abstract: Systems and corresponding methods are provided for navigating a data structure comprising a plurality of nodes. Each node in the data structure is associated with content from a content source and at least a keyword defining the content. The system receives a voice query to access content in one of the plurality of nodes. The system then recognizes one or more search keywords in the voice query based on a navigation grammar defined by a first active navigation scope associated with a first set of nodes in the data structure. The system then searches the first set of nodes to find a node with one or more keywords that best match the search keywords. The node that best matches the search keywords is then visited. The system provides content of the visited node.

Abstract: A method comprising: providing a navigation tree comprising a semantic, hierarchical structure, having one or more paths associated with content of a conventional markup language document and a grammar comprising vocabulary including one or more keywords; receiving a request to access the content; responsive to the request, traversing a path in the navigation tree, if the request includes at least one keyword of the vocabulary, is provided.

Abstract: Apparatus and methods for reducing the quantization error in shift-matrix finite impulse response (FIR) filters (210) operate on a sampled analog signal (11) converted to a sequence of digital signal samples (13). A weight conversion device (23) converts a weight signal W comprising a sequence of tap weights W.sub.i into both a corresponding series of logarithmically-encoded weights W'.sub.i and a series of weight error values .DELTA.W.sub.i. A multiplication device (30) multiplies each of the digital signal samples (13) with the first series of logarithmically-encoded weights W'.sub.i and provides the results to an accumulator (26). A signal encoding device (40) converts the digital signal samples (13) into a sequence of logarithmically-encoded digital signal samples (42). A quantization error correction device (220) multiplies each of the weight error values .DELTA.W.sub.i by the logarithmically-encoded digital signal samples (42) and also provides the results simultaneously to the accumulator (26).

Abstract: An electronic detection system for detecting vibration patterns from physical events, such as engine knocking or articulated speech, senses a vibration source with a wideband transducer to provide a sensed signal, then converts this signal to energy amplitude and spectral frequency form to extract detectable features of the vibration pattern. Events are detected when a controller determines that the sensed energy and spectral data exceed adaptively-predetermined energy and spectral thresholds, preferably for a duration exceeding predefined time windows.