176results about How to "Reduce Image Artifacts" patented technology

An apparatus and method using a backing block having a variable acoustic impedance as a function of elevation or azimuth, to achieve a desirable apodization of the aperture of an ultrasound transducer stacked with the backing block. The backing block has a gradient profile in acoustic impedance that changes from a minimum value to a maximum value along the elevation direction and / or azimuthal direction of the stacked ultrasound transducer. Typically, the backing block has an elevation gradient profile in acoustic impedance that increases from a minimum value of acoustic impedance near the center of the backing block to a maximum value of acoustic impedance at opposing lateral faces of the backing block. The backing block can be discretely segmented in acoustic impedance, with as many segments as are practically manufacturable. An individual segment can have a uniform or variable acoustic impedance. The backing block can be continuous in acoustic impedance, with a minimum acoustic impedance in the center and a maximum acoustic impedance at two or more planar lateral faces.

The methods and systems are provided that alleviate the impact of experimental systematic errors. These calibration methods and systems can be based on the discovery that by including source and detector calibration factors as part of the inverse calculation for image reconstruction, image artifacts can be significantly reduced. The novel methods and systems enhance contrast in images of the distribution of the radioactive properties of a medium, and enable improved detection of, for example, spatial variations in optical properties within highly scattering media, such as human or animal tissue. The novel methods and systems receive radiation which exits from the medium. Then, one or more optical properties of the medium are derived using the received radiation and one or more calibration factors, wherein the calibration factors are variables. Subsequently, a distribution of the optical properties in the medium is determined using the derived optical properties.

A liquid crystal display (LCD) and method of adjusting brightness for the LCD are provided. The LCD includes a light emitter including a plurality of luminescent bodies which are divided into a predetermined number of partial areas, a backlight driver connected to the light emitter to control the brightness of each of the partial areas of the light emitter, and a controller for calculating a representative value for adjusting the brightness of each of the partial areas of the light emitter in accordance with an input image signal and outputting the representative value as a brightness adjustment signal for adjusting the brightness of each of the partial areas to the backlight driver. Thus, the brightness of each of partial areas of a backlight can be adjusted in accordance with the input image signal to improve a contrast ratio. Also, a representative value to be used for adjusting the brightness of each of the partial areas can be lowered by a predetermined ratio to effectively reduce power needed for lighting the backlight. Also, light loss and light gain occurring between neighboring partial areas can be compensated to improve the contrast ratio, and image artifacts can be reduced.

A method for artifact management in a rotational imaging system is presented. The method includes the steps of acquiring data employing a helical scanning pattern over N revolutions, where N is greater than 1, and detecting at least one artifact in the acquired data of each revolution. The method further includes segmenting the data acquired over N revolutions into N-1 data frames each bounded by at least one of the at least one artifacts.

A method is provided for reducing image artifacts in printers that employ two or more printhead nozzle banks that must be aligned and registered with respect to each other either through adjustment of orientation and / or position of one nozzle bank relative to another or through selective control of actuation. In the method, discrete dots are printed by the nozzle banks upon a target receiver medium. Examination of the receiver medium or a reproduction thereof is made by a scanner and information regarding location of the dots is generated. From information regarding location of the dots a determination is made of error placement of the dots from ideal locations. Alignment of the nozzle banks are made in accordance with any errors determined in placement.

Certain embodiments of the present invention provide a method and system for improved calibration of an image acquisition device. Certain embodiments of the system include an image acquisition device for obtaining at least one image of an object and a calibration fixture positioned in relation to the image acquisition device. The calibration fixture includes a radiotranslucent material providing low frequency content for characterizing the image acquisition device. In an embodiment, the calibration fixture includes a plurality of peaks and valleys to create a low frequency signal for characterizing the image acquisition device. The calibration fixture may be positioned between the image acquisition device and an energy source such that a distance between the image acquisition device and the calibration fixture is minimized. In certain embodiments, a grating or other calibration fixture may be used to generate a moiré pattern to calibrate the image acquisition device.

Disclosed is a light guiding valve apparatus including a light valve, a two dimensional light emitting element array and an input side arranged to reduce light reflection for providing large area directional illumination from localized light emitting elements with low cross talk. A waveguide includes a stepped structure, in which the steps may include extraction features hidden to guided light propagating in a first forward direction. Returning light propagating in a second backward direction may be refracted or reflected by the features to provide discrete illumination beams exiting from the top surface of the waveguide. Stray light falling onto a light input side of the waveguide is at least partially absorbed.

A method for reducing, in an image, motion related imaging artifacts includes obtaining an image dataset of a region of interest, generating a plurality of intermediate images using the image dataset, applying a multivariate data analysis technique to the plurality of the intermediate images to generate motion information, sorting the intermediate images into a plurality of bins based on the motion information, and generating an image of the region of interest using at least one of the plurality of bins.

The invention is a novel adaptive CT-compatible brachytherapy applicator with remotely-controlled radial and longitudinal motion radioactive source lumen shields that can be manipulated by the radiation oncologist to optimize the dose distribution to the target and normal tissue structures for brachytherapy procedures.

An apparatus, system, and method for illuminating a lithographic mask or an object in a microscope is presented, whereby the output of a laser beam homogenizer is imaged on to a field such as the object plane for lithographic application or on to the rear focal plane of an epi illuminating objective lens as a source for wide field illumination at an object plane in a microscope (for application to magnified imaging of weak phase objects)., and the image of the output is dithered with respect to the field

A CT system includes a rotatable gantry having an opening for receiving an object to be scanned, at least one x-ray source coupled to the gantry and configured to project x-rays toward the object, a detector coupled to the gantry and having a scintillator therein and configured to receive x-rays that pass through the object, and a generator configured to energize the at least one x-ray source. The system includes a controller configured to energize the generator to project a first beam of x-rays toward the object from a first focal spot position of an anode, the first beam of x-rays having a ray traversing a path through the object, acquire imaging data from the first beam of x-rays, position the at least one x-ray source such that a second beam of x-rays projected from a second focal spot position of the anode has a ray directed to traverse the path through the object, the second anode focal spot position different than the first anode focal spot position, energize the generator to project the second beam of x-rays toward the object, and acquire imaging data from the second beam of x-rays.

Imaging devices having reduced image artifacts are disclosed. The image artifacts in the imaging devices are reduced by redirecting, absorbing or scattering IR radiation that passes through the imaging device substrate away from dark pixels.

An x-ray tube is described that includes components for increasing x-ray image clarity in the presence of a moving x-ray source by modifying focal spot characteristics, including focal spot size and focal spot position. In a first arrangement a static focal spot is moved in a direction contrary to the movement of the x-ray source so that an effective focal spot position is essentially fixed in space relative to one of the imaged object and / or detector during a tomosynthesis exposure. In a second arrangement, the size of the static focal spot is increased, and the resulting increase in tube current reduces the exposure time and concomitant blur effect. The methods may be used alone or in combination; for example an x-ray tube with a larger, moveable static focal spot will result in a system that fully utilizes the x-ray tube generator, provides a high quality image with reduced blur and, due to the decrease in exposure time, may scan the patient more quickly.

A method for reconstructing a high quality image from undersampled image data is provided. The image reconstruction method is applicable to a number of different imaging modalities. Specifically, the present invention provides an image reconstruction method that incorporates an appropriate prior image into the image reconstruction process. One aspect of the invention is to provide an image reconstruction method that produces a time series of desired images indicative of a higher temporal resolution than is ordinarily achievable with the imaging system, while mitigating undesired image artifacts. This is generally achieved by incorporating a limited amount of additional image data into the data consistency condition imposed during a prior image constrained image reconstruction. For example, cardiac phase images can be produced with high temporal resolution using a state-of-the-art multi-detector CT system with either fast gantry rotation speed or CT imaging system with a slow gantry rotation speed.

Disclosed is a light guiding valve apparatus including a light valve, a two dimensional light emitting element array and an input side arranged to reduce light reflection for providing large area directional illumination from localized light emitting elements with low cross talk. A waveguide includes a stepped structure, in which the steps may include extraction features hidden to guided light propagating in a first forward direction. Returning light propagating in a second backward direction may be refracted or reflected by the features to provide discrete illumination beams exiting from the top surface of the waveguide. Stray light falling onto a light input side of the waveguide is at least partially absorbed.

Ultrasonic strain measurements, which characterize the structure of tissue, may be obtained by combining multiple echo signals acquired at different compressions and at different angles. Such angular compounding may improve the quality of the elastic signal and provide at one time both an axial and lateral strain measurement.

A method and apparatus for reducing image artifacts on displays (e.g., electronic paper, etc.) are described. In one embodiment, the method comprises generating pixels of an image for a bistable display using halftoning based on data of one or more previously displayed images.

The invention is a novel adaptive CT-compatible brachytherapy applicator with remotely-controlled radial and longitudinal motion radioactive source lumen shields that can be manipulated by the radiation oncologist to optimize the dose distribution to the target and normal tissue structures for brachytherapy procedures.

A CT system includes a rotatable gantry having an opening for receiving an object to be scanned and an x-ray source coupled to the gantry and configured to project x-rays through the opening. The x-ray source includes a target, a first cathode configured to emit a first beam of electrons toward the target, a first gridding electrode coupled to the first cathode, a second cathode configured to emit a second beam of electrons toward the target, and a second gridding electrode coupled to the second cathode. The system includes a generator configured to energize the first cathode to a first kVp and to energize the second cathode to a second kVp, and a detector attached to the gantry and positioned to receive x-rays that pass through the opening. The system also includes a controller configured to apply a gridding voltage to the first gridding electrode to block emission of the first beam of electrons toward the target, apply the gridding voltage to the second gridding electrode to block emission of the second beam of electrons toward the target, and acquire dual energy imaging data from the detector.

A method for reconstructing a high quality image from undersampled image data is provided. The image reconstruction method is applicable to a number of different imaging modalities. Specifically, the present invention provides an image reconstruction method that incorporates an appropriate prior image into the image reconstruction process. One aspect of the invention is to provide an image reconstruction method that produces a time series of desired images indicative of a higher temporal resolution than is ordinarily achievable with the imaging system, while mitigating undesired image artifacts. This is generally achieved by incorporating a limited amount of additional image data into the data consistency condition imposed during a prior image constrained image reconstruction. For example, cardiac phase images can be produced with high temporal resolution using a state-of-the-art multi-detector CT system with either fast gantry rotation speed or CT imaging system with a slow gantry rotation speed.

A method and apparatus are provided for reducing motion related imaging artifacts. The method includes obtaining an image data set of a region of interest in an object, obtaining a motion signal indicative of motion of the region of interest, determining at least one quiescent period of at least a portion of the motion signal, extracting image data from the image data set that is within the determined quiescent period to form an image data subset, and generating an image of the region of interest using the image data subset.

A color projection display in which at least one color channel includes: a light source assembly including a multiplicity of pulse modulated light sources providing an aggregate light beam; a light modulation control subsystem; illumination optics to direct the aggregate light beam to an image modulation plane; and a spatial light modulator in the image modulation plane. The light modulation control subsystem senses an aggregate light intensity signal for the aggregate light beam and controls the pulse modulation parameters for the multiplicity of pulse-modulated light sources responsive to the sensed aggregate light intensity signal to reduce light intensity fluctuations in the aggregate light beam within the imaging time interval.

To prepare magnetization for steady state magnetic resonance imaging, magnetic resonance is primed using a parameterized priming sequence (60). The parameterized priming sequence (60) has a spectral offset parameter value (40) corresponding to a spectral offset of the steady state imaging. Subsequent to the priming, steady state magnetic resonance imaging data at the first spectral offset is acquired using a magnetic resonance imaging scanner (10). A reconstruction processor (44) reconstructs the imaging data to generate an image representation. Preferably, the parameterized priming sequence (60) includes a longitudinal priming sequence (62) that prepares longitudinal magnetization in a state approximating a steady state longitudinal magnetization. A spoiler sequence (64) spoils transverse magnetization while retaining longitudinal magnetization. A transverse priming sequence (66) prepares traverse magnetization in a state approximating a steady state transverse magnetization.

An x-ray tube is described that includes components for increasing x-ray image clarity in the presence of a moving x-ray source by modifying focal spot characteristics, including focal spot size and focal spot position. In a first arrangement a static focal spot is moved in a direction contrary to the movement of the x-ray source so that an effective focal spot position is essentially fixed in space relative to one of the imaged object and / or detector during a tomosynthesis exposure. In a second arrangement, the size of the static focal spot is increased, and the resulting increase in tube current reduces the exposure time and concomitant blur effect. The methods may be used alone or in combination; for example an x-ray tube with a larger, moveable static focal spot will result in a system that fully utilizes the x-ray tube generator, provides a high quality image with reduced blur and, due to the decrease in exposure time, may scan the patient more quickly.

Certain embodiments of the present invention provide a method and system for improved calibration of an image acquisition device. Certain embodiments of the system include an image acquisition device for obtaining at least one image of an object and a calibration fixture positioned in relation to the image acquisition device. The calibration fixture includes a radiotranslucent material providing low frequency content for characterizing the image acquisition device. In an embodiment, the calibration fixture includes a plurality of peaks and valleys to create a low frequency signal for characterizing the image acquisition device. The calibration fixture may be positioned between the image acquisition device and an energy source such that a distance between the image acquisition device and the calibration fixture is minimized. In certain embodiments, a grating or other calibration fixture may be used to generate a moiré pattern to calibrate the image acquisition device.

The invention relates to a device and to a method for magnetic resonance imaging (MRI) of a body. It is an object of the invention to provide a technique that enables dynamic profile sharing with significantly reduced motion artifacts. The method of the (such as keyhole) invention comprises the following steps: a) acquiring an MR data set (21) from an incomplete first part of k-space (C) by subjecting the body to an imaging sequence of RF pulses and switched magnetic field gradients; b) reconstructing an incomplete MR image (31) from the MR data set (21) acquired in step a) and deriving image transformation parameters describing motion of the body from the reconstructed incomplete MR image (31), -c) acquiring an MR data set (24) from an incomplete second part of k-space (P), which second part (P) is different from the first part (C) sampled in step a); d) applying a motion correction (40) to at least one of the MR data sets (21, 24) acquired in steps a) and c) according to the image transformation parameters derived in step b); e) reconstructing a final MR image (81) from a combination (71) of the motion-corrected MR data sets (61, 64).

The invention relates to a geometry correction method of an X-ray computed tomography imaging system, which is especially suitable for geometry parameter correction of pencil beam and fan beam computed tomography imaging systems of a circular orbit. Horizontal offset of an X-ray detector is accurately estimated by using X-ray detector offset information of the computed tomography imaging system, included in linear mold X-ray computed tomography imaging three-dimensional reconstruction data; and the geometry correction of the X-ray computed tomography imaging system can be carried out by using the obtained horizontal offset, thereby improving the spatial resolution of the X-ray computed tomography imaging system and reducing the image artifacts.

Imaging devices having reduced image artifacts are disclosed. The image artifacts in the imaging devices are reduced by redirecting, absorbing or scattering IR radiation that passes through the imaging device substrate away from dark pixels.

Various methods and systems are provided for reconstructing magnetic resonance images from accelerated magnetic resonance imaging (MRI) data. In one embodiment, a method for reconstructing a magnetic resonance (MR) image includes: estimating multiple sets of coil sensitivity maps from undersampled k-space data, the undersampled k-space data acquired by a multi-coil radio frequency (RF) receiver array; reconstructing multiple initial images using the undersampled k-space data and the estimated multiple sets of coil sensitivity maps; iteratively reconstructing, with a trained deep neural network, multiple images by using the initial images and the multiple sets of coil sensitivity maps to generate multiple final images, each of the multiple images corresponding to a different set of the multiple sets of sensitivity maps; and combining the multiple final images output from the trained deep neural network to generate the MR image.

A system and method include a computer readable storage medium having stored thereon a computer program comprising instructions which when executed by a computer cause the computer to apply a first plurality of radio frequency (RF) pulses during a first repetition time (TR) interval of a magnetic resonance (MR) pulse sequence. The instructions also cause the computer to apply a first plurality of gradient pulses and acquire the MR data during application of each gradient pulse of the first plurality of gradient pulses between an adjacent pair of RF pulses of the first plurality of RF pulses. Each gradient pulse of the first plurality of gradient pulses is configured to allow acquisition of MR data for a respective first bladelet passing through a center of k-space, wherein the first bladelets are non-parallel with each other. The instructions also cause the computer to reconstruct the acquired MR data into an image.