Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: One or more techniques and/or systems for compressing signals yielded from a CT examination are provided. The signals are encoded, or remapped, into a format in which the photon noise of the signals are substantially constant over a dynamic range while the signals are in a projection space domain. That is, the signals are encoded into a format in which the standard deviation of the photon noise does not change based upon the number of photons detected. Once remapped into such a format, the noise entropy of the signals may be set to a predetermined level (e.g., a minimum value that preserves the information in the signals). The signals may then be compressed using a compression technique. In one embodiment, the compression can reduce the amount of data comprised within the signals by a factor of 2.5 or more relative to an analog, linear formatted, signal that was generated by a pixel of the detector array.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.