Analogic Corporation

Enrico Dolazza

Hans J Weedon

Wei Zhao

Louis R Poulo

Sorin Marcovici

Olivier Tousignant

Roger Finch

Luc Laperriere

Jonathan Greenspan

Bernard M Gordon

William M Wong

Douglas Q Abraham

Martin Choquette

Aleksander Roshi

Richard H McMorrow, Jr

Alexander Kolchinsky

Jeremy L Muller

Oscar Khutoryansky

Matthew Bieniosek

Richard McMorrow

Michael Lachmayr

James G Coffin

Louis Poulo

One or more techniques and/or systems described herein implement, among other things, a parabolic curve for a ramp signal in a data acquisition component, where the curve can be effectively calibrated and used to provide a settling period to mitigate noise. That is, a ramp generator can generate a ramp signal that has a parabolic voltage curve with two substantially mirroring halves. A comparator can compare a first portion of the parabolic voltage curve with a voltage signal indicative of a number of photons detected by a detection array. A second portion of the parabolic voltage curve is used as a temporal delay so that circuitry, such as the ramp generator, can settle.

Non-linear data acquisition

Tomosynthesis data may be acquired from an ionizing radiation source that substantially continuously emits radiation while its position is varied relative to a photon counting detector. The detector detects photons comprised within the radiation and photon data indicative of the detected photons is generated. The photon data may comprise data related to a detected photon's detection time, detection location on the detector, energy level, and/or trajectory from the radiation source, for example. The photon data of various photons may be compiled into a plurality of bins and, through reconstruction and tomosynthesis techniques, produce synthesized images of various tomography planes of an object under examination. In this way, the tomosynthesis techniques rely on counting photons rather than measuring their energy to create synthesized images.

Method of and apparatus for continuous wave tomosynthesis using photon counting

Tomosynthesis data may be acquired from a radiation source that substantially continuously emits radiation while its position is varied relative to a photon counting x-ray detector. The detector detects photons comprised within the radiation and photon data indicative of the detected photons is generated. The photon data may comprise data related to a detected photon's detection time, detection location on the detector, energy level, and/or trajectory from the radiation source, for example. The photon data of various photons may be compiled into a plurality of bins and, through reconstruction and tomosynthesis techniques, produce synthesized images of various tomography planes of an object under examination. In this way, the tomosynthesis techniques rely on counting photons rather than measuring their energy to create synthesized images.

A sigma delta analog to digital converter of the type adapted to be connected to a capacitive current input device, comprises: a sigma delta modulator having an input; and a flying capacitor constructed so as to be connected between the input of the sigma delta modulator and the capacitive current input device. In a preferred embodiment, the converter includes an input stage having an input coupled to the flying capacitor; a feedback path; a digital to analog converter (DAC) disposed in the feedback path and having a DAC output; and a DAC output capacitor and a second switch for alternately switching the DAC output capacitor between a first connection so as to transfer a signal from the output of the digital to analog converter to the DAC output capacitor and a second connection so as to transfer a signal from the DAC output capacitor to the input of the sigma delta modulator. The flying capacitor includes a charging capacitor and a flying capacitor switch, the flying capacitor being constructed so as to be alternately switched between a first connection so as to transfer a signal from the capacitive current input device to the charging capacitor and a second connection so as to transfer a signal from the charging capacitor to the input of the sigma delta modulator. The switching frequency of both switches is preferably operated at the same frequency fso as to define a common switching cycle for both the flying capacitor switch and the second switch, and synchronized so that the flying capacitor switch and the second switch are each switched to the first connection during one phase of the switching cycle and switched to the second connection during a second phase of the switching cycle. The converter has particular utility for any device having capacitive current input devices, such as CAT scanner detectors and electret microphones. The disclosure also describes and claims a method of converting a current provided by a capacitive current input device to a digital signal using a sigma delta analog to digital converter.

Sigma delta converter with flying capacitor input

A charge transfer system includes a current-based input device for generating an input current signal, a temporary energy storage device, and an amplification device. A switching device couples the temporary energy storage device to the current-based input device during a first portion of a time period and to the amplification device during a second portion of a time period. The input current signal charges the temporary energy storage device, during the first portion of the time period, to generate an input voltage signal. The amplification device receives the input voltage signal during the second portion of the time period.

Charge transfer system and method

A method of providing a spatially filtered version of an image by selectively modifying image pixel amplitudes as a predetermined function of spatial frequency components of the image pixels includes dividing an overall frequency range of the image into a plurality of constituent frequency ranges. The method provides, for each of the constituent frequency ranges, a spatial filter for receiving the image pixels and producing a filtered output representative of the spatial frequency components of the pixels that are within that constituent frequency range. The method further includes scaling each of the filtered outputs by a scaling factor specific to the associated spatial filter, so as to produce a scaled output. Finally, the method includes combining the scaled outputs to produce a composite output representative of the spatially filtered version of the image. The scaling factors may include a predetermined set of values for a particular filter response, or the scaling factors may be time-varying so that the filter response changes as a function of time.

Sweeping spatial filter system and method

A method of and system for decreasing X-ray exposure time in a full field digital mammography (FFDM) system is designed so that the size of the focal spot image in the image plane is dimensioned as a function of the linear size of the pixel of the digital detector of the detector array and of the geometrical magnification factor of the focal spot so that the modular transfer function is limited only by the pixel size.

Method of and system for decreasing x-ray exposure times in full field digital mammography

A system for adaptively filtering an image so as to reduce a noise component associated with the image includes an image analyzer for determining image parameters related to the image. The system also includes a spatial filter, having an adjustable kernel responsive to the image parameters, for filtering the image sequence. The image analyzer manipulates the filter kernel as a function of the image parameters so that the system produces a filtered image, adaptable in real time, as a function of the unfiltered image, external rules, predetermined constraints, or combinations thereof. The spatial filter includes a time-invariant section and an adaptable section. The time-invariant section preferably applies a plurality of filters to the image, each of the filters having a distinct frequency response, so as to produce a plurality of distinct filtered outputs. The adaptable section scales each of the plurality of distinct filtered outputs with a corresponding distinct weighting value to produce a plurality of scaled filtered outputs, and combines the plurality of scaled filtered outputs to produce a composite filtered output.

Adaptive spatial filter

A method of improving the signal to noise ratio associated with the output of a digital x-ray detector receiving bi-chromatic x-ray energy includes acquiring a first image from the detector corresponding to x-ray energy at a first energy level, and scaling the first image with a first scaling factor so as to produce a scaled first image. The method further includes acquiring a second image from the detector corresponding to x-ray energy at a second energy level, and scaling the second image with a second scaling factor so as to produce a second scaled image. The method also includes combining the first scaled image and the second scaled image so as to form a compensated image.

Method of and system for improving the signal to noise characteristics of images from a digital X-ray detector receiving bi-chromatic X-ray energy

A data acquisition system for use in a CT scanner comprises an analog-to-digital converter for generating digital signals in response to analog signals representative of projection data taken at a relatively constant sampling rate; and an interpolation filter for generating projection data for a plurality of predetermined projection angles as a function of the digital signals irrespective of the sampling rate.

Data acquisition system for generating accurate projection data in a CT

An ultrasound beamformer that processes the signals of an array transducer includes a plurality of processing channels, one for each element of the active transducer array. Each channel includes a digitizing element for converting the received signal into digital samples and a delay element for delaying the digitized signal. The delays are chosen so that when the signals from the individual channels are combined, a beam forms in a particular direction. The invention implements sub-sampling period delays in the individual channels with low-complexity digital filters having superior delay characteristics with respect to frequency, but having undesirable attenuation characteristics with respect to frequency. The invention corrects for the undesirable attenuation characteristics via a single digital filter after the signals from the individual channels have been combined.

Method and apparatus for delaying ultrasound signals

An array transducer ultrasound beamformer includes a plurality of processing channels, one for each active element of the transducer array. Each channel includes a digitizing unit for converting the received signal to digital samples and a time multiplexed delay unit for producing a primary stream of delayed TDM samples corresponding to one or more beams. Within each channel, the primary stream of delayed TDM samples is demultiplexed in order to separate the stream in a plurality of secondary streams of delayed TDM samples, wherein each of the secondary streams corresponds to a portion of a beam or a single beam.

Digital ultrasound beamformer

An improved data acquisition system filter, optimized for the time domain and for use in a computed tomography scanner of the type using x-ray focal spot wobble, includes a filter time response F(t) which is a function of the waveform w(t) used to drive the focal spot from one position to the other.

Optimal channel filter for CT system with wobbling focal spot

A system for and method of compensating for performance differences in a set of information channels is disclosed. The system and method model each channel as linear and characterizes the channel by an offset and a gain. The system includes memory for storing the offsets and gains associated with the N channels. The system further includes means for mathematically adjusting the output of each information channel by that channel's associated offset and gain. The system further includes filters for reducing the effect of random noise on the measurements of the offsets and gains by generating signals representative of time weighted averages of the offsets and gains.

Continuous self-calibrating data acquistion system

The disclosed ultrasound system processes ultrasound signals having centroid frequencies that decrease as a function of time. The system includes transducers for receiving the ultrasound signals and generating electrical signals representative thereof. The system further includes data samplers for sampling the electrical signals with a sampling frequency. A controller controls the sampling frequency so that it decreases according to a function of time and the centroid frequency.

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Boston, MA, United States of America

Enrico Dolazza