409 results about "Motion correction" patented technology

An image data set acquired by an optical coherence tomography (OCT) system is corrected for effects due to motion of the sample. A first set of A-scans is acquired within a time short enough to avoid any significant motion of the sample. A second more extensive set of A-scans is acquired over an overlapping region on the sample. Significant sample motion may occur during acquisition of the second set. A-scans from the first set are matched with A-scans from the second set, based on similarity between the longitudinal optical scattering profiles they contain. Such matched pairs of A-scans are likely to correspond to the same region in the sample. Comparison of the OCT scanner coordinates that produced each A-scan in a matching pair, in conjunction with any shift in the longitudinal scattering profiles between the pair of A-scans, reveals the displacement of the sample between acquisition of the first and second A-scans in the pair. Estimates of the sample displacement are used to correct the transverse and longitudinal coordinates of the A-scans in the second set, to form a motion-corrected OCT data set.

Current MRI technologies require subjects to remain largely motionless for achieving high quality magnetic resonance (MR) scans, typically for 5-10 minutes at a time. However, lying absolutely still inside the tight MR imager (MRI) tunnel is a difficult task, especially for children, very sick patients, or the mentally ill. Even motion ranging less than 1 mm or 1 degree can corrupt a scan. This invention involves a system that adaptively compensates for subject motion in real-time. An object orientation marker, preferably a retro-grate reflector (RGR), is placed on a patients' head or other body organ of interest during MRI. The RGR makes it possible to measure the six degrees of freedom (x, y, and z-translations, and pitch, yaw, and roll), or “pose”, required to track the organ of interest. A camera-based tracking system observes the marker and continuously extracts its pose. The pose from the tracking system is sent to the MR scanner via an interface, allowing for continuous correction of scan planes and position in real-time. The RGR-based motion correction system has significant advantages over other approaches, including faster tracking speed, better stability, automatic calibration, lack of interference with the MR measurement process, improved ease of use, and long-term stability. RGR-based motion tracking can also be used to correct for motion from awake animals, or in conjunction with other in vivo imaging techniques, such as computer tomography, positron emission tomography (PET), etc.

A method of correcting for motion in magnetic resonance images of an object detected by a plurality of signal receiver coils comprising the steps of acquiring a plurality of image signals with the plurality of receiver coils, determining motion between sequential image signals relative to a reference, applying rotation and translation to image signals to align image signals with the reference, determining altered coil sensitivities due to object movement during image signal acquisition, and employing parallel imaging reconstruction of the rotated and translated image signals using the altered coil sensitivities in order to compensate for undersampling in k-space.

An electronic image stabilizer in a digital camera compensates for camera motion-induced blurriness by segmenting exposure times into multiple shorter exposure times and summing the individual pixels from successive frames after applying an appropriate motion correction. Motion is detected by computing the correlation function between successive images, and compensation is applied by maximizing the correlation function. This avoids the need for mechanical stabilization devices in order to detect or correct the motion as is done in prior art. This method further enables the detection of moving objects in a still background, and correction of blurriness images due to such motion.

In a multi-shot method for diffusion-weighted imaging in magnetic resonance tomography, the sampling of the k-matrix in the readout direction ensues in segments, and immediately after acquisition of an image data set by readout of one segment by means of echo signals, a navigation data set is acquired by readout of the middle region of the k-matrix at virtually the same time. A movement-corrected diffusion-weighted MRT image is generated by combining of the image data sets with the corresponding navigation data sets and subsequent Fourier transformation.

Current MRI technologies require subjects to remain largely motionless for achieving high quality magnetic resonance (MR) scans, typically for 5-10 minutes at a time. However, lying absolutely still inside the tight MR imager (MRI) tunnel is a difficult task, especially for children, very sick patients, or the mentally ill. Even motion ranging less than 1 mm or 1 degree can corrupt a scan. This invention involves a system that adaptively compensates for subject motion in real-time. An object orientation marker, preferably a retro-grate reflector (RGR), is placed on a patients' head or other body organ of interest during MRI. The RGR makes it possible to measure the six degrees of freedom (x, y, and z-translations, and pitch, yaw, and roll), or “pose”, required to track the organ of interest. A camera-based tracking system observes the marker and continuously extracts its pose. The pose from the tracking system is sent to the MR scanner via an interface, allowing for continuous correction of scan planes and position in real-time. The RGR-based motion correction system has significant advantages over other approaches, including faster tracking speed, better stability, automatic calibration, lack of interference with the MR measurement process, improved ease of use, and long-term stability. RGR-based motion tracking can also be used to correct for motion from awake animals, or in conjunction with other in vivo imaging techniques, such as computer tomography, positron emission tomography (PET), etc.

One or more techniques are provided for adapting a reconstruction process to account for the motion of an imaged object or organ, such as the heart. In particular, projection data of the moving object or organ is acquired using a slowly rotating CT gantry. Motion data may be determined from the projection data or from images reconstructed from the projection data. The motion data may be used to reconstruct motion-corrected images from the projection data. The motion-corrected images may be associated to form motion-corrected volume renderings.

An X-ray imaging method forms a set of a plurality of two-dimensional X-Ray projection images of a medical or veterinary object to be examined through a scanning rotation by an X-Ray source viz à viz the object. Such X-Ray images are acquired at respective predetermined time instants with respect to a functionality process produced by the object. From said set of X-Ray projection images by back-projection a three-dimensional volume image of the object is reconstructed. In particular, an appropriate motion correction is derived for the respective two-dimensional images, and subsequently as based on a motion vector field from the various corrected two-dimensional images the intended three-dimensional volume is reconstructed.

A method is provided for averaging a sequence of image frames. A noise-reducing filter is applied to the image frames to generate filtered frames. A deconvolution filter is applied to the filtered frames to generate corresponding deconvolved frames. The filtered frames are transformed by an affine transformation to align them, generating aligned frames. The aligned frames are motion corrected by non-linear transformation based on intensity rank matching, generating a sequence of motion-corrected frames. The motion-corrected frames are averaged to generate a resultant frame.

An interlace-to-progressive scan conversion system comprises: a spatial line averaging prefilter; a motion estimator; a three-stage adaptive recursive filter. The motion estimator comprises: a 3-D recursive search sub-component having a bilinear interpolator; a motion correction sub-component having an error-function including penalties related to the difference between a given candidate vector and a plurality of neighboring vectors; a block erosion sub-component. The motion estimator assumes that motion is constant between fields. The three-stage adaptive recursive filter comprises: a first stage that selects between using static pixels data and moving pixels data from a next field; a second stage that selects a more valid set of data between motion compensated data from a previous field and the pixels selected by the first stage; a third stage that combines an intra-field interpolation with the more valid set of data selected by the second stage.

In a magnetic resonance tomography apparatus and method with motion correction in an angiography examination with magnetic resonance-monitored vessel intervention, a contrast agent-supported exposure of the vessel system (road map) is registered, with one exposure ensuing at the end of expiration and one exposure ensuing at the end of inspiration of the patient, and a magnetic resonance-visible medical intervention device introduced into the vessel system also is registered. A corrected road map of the vessel system is interpolated from the exposures at the end of inspiration and the end of expiration and the exposure of the intervention device is superimposed on the corrected road map.