Abstract: Diffuse image measurement system and digital image formation method. The system includes a source of light with time-varying intensity directed at a scene to be imaged. A time-resolved light meter is provided for receiving light reflected from the scene to generate time-resolved samples of the intensity of light incident at the light meter. The temporal variation in the intensity of light incident at the light meter is associated with a function of a radiometric property of the scene, such as a linear functional of reflectance, and a computer processes the samples to construct a digital image. The spatial resolution of the digital image is finer than the spatial support of the illumination on the scene and finer than the spatial support of the sensitivity of the light meter. Using appropriate light sources instead of impulsive illumination significantly improves signal-to-noise ratio and reconstruction quality.

Abstract: An MR imaging system uses multiple RF coils for acquiring corresponding multiple image data sets of a slice or volume of patient anatomy. An image data processor comprises at least one processing device conditioned for, deriving a first set of weights for weighted combination of k-space data of the multiple image data sets for generating a calibration data set comprising a subset of k-space data of composite image data representing the multiple image data sets. The image data processor uses the calibration data set in generating a first MR image data set, deriving the parameters of a probability distribution in response to the first set of weights and the first MR image data set and deriving a second set of weights and second MR image data set together using the probability distribution.

Abstract: A system for parallel image processing in MR imaging comprises multiple MR imaging RF coils for individually receiving MR imaging data representing a slice of patient anatomy. An MR imaging system uses the multiple RF coils for acquiring corresponding multiple image data sets of the slice. An image data processor comprises at least one processing device conditioned for, deriving a first set of weights for generating a calibration data set comprising a subset of k-space data of composite image data representing the multiple image data sets. The at least one processing device uses the calibration data set in generating a first MR image data set, deriving a second set of weights using the calibration data set and the generated first MR image data set and uses the second set of weights in generating a second MR image data set representing a single image having a reduced set of data components relative to the first composite MR image data set.

Abstract: Described herein is a sampling system and related sampling scheme. The system and sampling scheme is based upon a framework for adaptive non-uniform sampling schemes. In the system and schemes described herein, time intervals between samples can be computed by using a function of previously taken samples. Therefore, keeping sampling times (time-stamps), except initialization times, is not necessary. One aim of this sampling framework is to provide a balance between reconstruction distortion and average sampling rate. The function by which sampling time intervals can be computed is called the sampling function. The sampling scheme described herein can be applied appropriately on different signal models such as deterministic or stochastic, and continuous or discrete signals. For each different signal model, sampling functions can be derived.

Abstract: Depth information about a scene of interest is acquired by illuminating the scene, capturing reflected light energy from the scene with one or more photodetectors, and processing resulting signals, in at least one embodiment, a pseudo-randomly generated series of spatial light modulation patterns is used to modulate the light pulses either before or after reflection.

Abstract: An MR imaging system uses the multiple RF coils for acquiring corresponding multiple image data sets of the slice. An image data processor comprises at least one processing device conditioned for, generating a composite MR image data set representing a single image in a single non-iterative operation by performing a weighted combination of luminance representative data of individual corresponding pixels of the multiple image data sets in providing an individual pixel luminance value of the composite MR image data set. The image data processor reduces noise in the composite MR image data set by generating a reduced set of significant components in a predetermined transform domain representation of data representing the composite image to provide a de-noised composite MR image data set. An image generator comprises at least one processing device conditioned for, generating a composite MR image using the de-noised composite MR image data set.

Abstract: Described herein is a sampling system and related sampling scheme. The system and sampling scheme is based upon a framework for adaptive non-uniform sampling schemes. In the system and schemes described herein, time intervals between samples can be computed by using a function of previously taken samples. Therefore, keeping sampling times (time-stamps), except initialization times, is not necessary. One aim of this sampling framework is to provide a balance between reconstruction distortion and average sampling rate. The function by which sampling time intervals can be computed is called the sampling function. The sampling scheme described herein can be applied appropriately on different signal models such as deterministic or stochastic, and continuous or discrete signals. For each different signal model, sampling functions can be derived.

Abstract: An MR imaging system uses multiple RF coils for acquiring corresponding multiple image data sets of a slice or volume of patient anatomy. An image data processor comprises at least one processing device conditioned for, deriving a first set of weights for weighted combination of k-space data of the multiple image data sets for generating a calibration data set comprising a subset of k-space data of composite image data representing the multiple image data sets. The image data processor uses the calibration data set in generating a first MR image data set, deriving the parameters of a probability distribution in response to the first set of weights and the first MR image data set and deriving a second set of weights and second MR image data set together using the probability distribution.

Abstract: A system for parallel image processing in MR imaging comprises multiple MR imaging RF coils for individually receiving MR imaging data representing a slice of patient anatomy. An MR imaging system uses the multiple RF coils for acquiring corresponding multiple image data sets of the slice. An image data processor comprises at least one processing device conditioned for, deriving a first set of weights for generating a calibration data set comprising a subset of k-space data of composite image data representing the multiple image data sets. The at least one processing device uses the calibration data set in generating a first MR image data set, deriving a second set of weights using the calibration data set and the generated first MR image data set and uses the second set of weights in generating a second MR image data set representing a single image having a reduced set of data components relative to the first composite MR image data set.

Abstract: Depth information about a scene of interest is acquired by illuminating the scene, capturing reflected light energy from the scene with one or more photodetectors, and processing resulting signals, in at least one embodiment, a pseudo-randomly generated series of spatial light modulation patterns is used to modulate the light pulses either before or after reflection.

Abstract: Diffuse image measurement system and digital image formation method. The system includes a source of light with time-varying intensity directed at a scene to be imaged. A time-resolved light meter is provided for receiving light reflected from the scene to generate time-resolved samples of the intensity of light incident at the light meter. The temporal variation in the intensity of light incident at the light meter is associated with a function of a radiometric property of the scene, such as a linear functional of reflectance, and a computer processes the samples to construct a digital image. The spatial resolution of the digital image is finer than the spatial support of the illumination on the scene and finer than the spatial support of the sensitivity of the light meter. Using appropriate light sources instead of impulsive illumination significantly improves signal-to-noise ratio and reconstruction quality.

Abstract: A system and method is provided for simultaneously designing a radiofrequency (“RF”) pulse waveform and a magnetic field gradient waveform in a magnetic resonance imaging (“MRI”) system. The method includes determining a desired pattern of RF excitation and determining, from the desired pattern of RF excitation, a plurality of k-space locations indicative of the magnetic field gradient waveform and a plurality of complex weighting factors indicative of RF energy deposited at each k-space location. The method also includes calculating, from the determined k-space locations, the magnetic field gradient waveform and calculating, from the complex weighting factors, the RF pulse waveform that will produce the desired pattern of RF excitation when produced with the calculated magnetic field gradient.

Abstract: An MR imaging system uses the multiple RF coils for acquiring corresponding multiple image data sets of the slice. An image data processor comprises at least one processing device conditioned for, generating a composite MR image data set representing a single image in a single non-iterative operation by performing a weighted combination of luminance representative data of individual corresponding pixels of the multiple image data sets in providing an individual pixel luminance value of the composite MR image data set. The image data processor reduces noise in the composite MR image data set by generating a reduced set of significant components in a predetermined transform domain representation of data representing the composite image to provide a de-noised composite MR image data set. An image generator comprises at least one processing device conditioned for, generating a composite MR image using the de-noised composite MR image data set.

Abstract: A method for target-dependent, sparsity-enforced selection for choosing a substantially optimal connection of radiofrequency (“RF”) transmitters to the elements of the RF coil array is provided. In particular, a method is provided that selects the linear combinations of the “N” spatial mode profiles of a transmission RF coil array, such that the k-space trajectory and pulse duration acceleration capabilities of the array are advantageously utilized. A sparsity-enforcement method that determines a subset of the available spatial modes for a parallel transmission RF coil array is employed to this end. In this manner, the utilization of the encoding power of a highly-parallel N-mode coil array in a system with only “P” available excitation channels is enabled.

Abstract: A method for target-dependent, sparsity-enforced selection for choosing a substantially optimal connection of radiofrequency (“RF”) transmitters to the elements of the RF coil array is provided. In particular, a method is provided that selects the linear combinations of the “N” spatial mode profiles of a transmission RF coil array, such that the k-space trajectory and pulse duration acceleration capabilities of the array are advantageously utilized. A sparsity-enforcement method that determines a subset of the available spatial modes for a parallel transmission RF coil array is employed to this end. In this manner, the utilization of the encoding power of a highly-parallel N-mode coil array in a system with only “P” available excitation channels is enabled.

Abstract: A system and method is provided for simultaneously designing a radiofrequency (“RF”) pulse waveform and a magnetic field gradient waveform in a magnetic resonance imaging (“MRI”) system. The method includes determining a desired pattern of RF excitation and determining, from the desired pattern of RF excitation, a plurality of k-space locations indicative of the magnetic field gradient waveform and a plurality of complex weighting factors indicative of RF energy deposited at each k-space location. The method also includes calculating, from the determined k-space locations, the magnetic field gradient waveform and calculating, from the complex weighting factors, the RF pulse waveform that will produce the desired pattern of RF excitation when produced with the calculated magnetic field gradient.

Abstract: A signal processing device utilizes a stochastic approximation of a gradient descent algorithm for updating a transform. The signal processing device is configured to implement the transform for producing a desired transformed output signal, and the transform is updated using the stochastic approximation of the gradient algorithm based on received data associated with the signal being processed. The transform is represented in a reduced-parameter form, such as a Givens parameterized form or a Householder form, such that the reduced-parameter form for an N×N transform comprises fewer than N2 parameters. The updating process is implemented using computations involving the reduced-parameter form, and an adaptation of the transform is represented directly as one or more changes in the reduced-parameter form. The gradient algorithm may be configured to minimize a negative gradient of a pairwise energy compaction property of the transform.

Abstract: A multiple description coder generates a number of different descriptions of a given portion of a signal in a wireless communication system, using multiple description scalar quantization (MDSQ) or another type of multiple description coding. The different descriptions of the given portion of the signal are then arranged into packets such that at least a first description of the given portion is placed in a first packet and a second description is placed in a second packet. Each of the packets are then transmitted using a frequency hopping modulator, and the hopping rate of the modulator is selected or otherwise configured based at least in part on the number of descriptions generated for the different portions of the signal.

Abstract: A lattice-structured multiple description vector quantization (LSMDVQ) encoder generates M descriptions of a signal to be encoded, each of the descriptions being transmittable over a corresponding one of M channels. The encoder is configured based at least in part on a distortion measure which is a function of a central distortion and at least one side distortion. For example, if M=2, the distortion measure may be an average mean-squared error (AMSE) function of the form ƒ(D0, D1, D2), where D0 is a central distortion resulting from reconstruction based on receipt of both a first and a second description, and D1 and D2 are side distortions resulting from reconstruction using only a first description and a second description, respectively. Further performance improvements may be obtained through perturbation of the lattice points.

Abstract: A multiple description (MD) joint source-channel (JSC) encoder in accordance with the invention encodes n components of a signal for transmission over in channels of a communication medium. In illustrative embodiments, the invention provides optimal or near-optimal transforms for applications in which at least one of n and m is greater than two, and applications in which the failure probabilities of the m channels are non-independent and non-equivalent. The signal to be encoded may be a data signal, a speech signal, an audio signal, an image signal, a video signal or other type of signal, and each of the m channels may correspond to a packet or a group of packets to be transmitted over the medium. A given n×m transform implemented by the MD JSC encoder may be in the form of a cascade structure of several transforms each having dimension less than n×m. The transform may also be configured to provide a substantially equivalent rate for each of the m channels.