Abstract: A robust initial frame detection and symbol synchronization system and methodology are provided. In particular, a first pilot is employed in conjunction with three acquisition stages. In the first stage, an attempt is made to observe the leading edge of the correlation curve associated with the first pilot symbol. In the second stage, a determination is made as to whether a leading edge was detected in the first stage by attempting to observe a flat portion and/or trailing edge of the correlation curve. Furthermore, during this second stage, a frequency loop can be updated to account for frequency offset. The third stage is for observing the trailing edge of the curve if it was not already observed in stage two. Upon detection and confirmation of receipt of the first pilot, a second pilot can subsequently be employed to acquire fine symbol timing.

Abstract: A timing estimation system and methodology are provided. In particular, a first pilot is employed in conjunction with three acquisition stages. In the first stage, an attempt is made to observe the leading edge of the correlation curve associated with the first pilot symbol. In the second stage, a determination is made to confirm a leading edge was detected in the first stage by attempting to observe a trailing edge of the correlation curve. Furthermore, during this second stage, a frequency loop is updated to account for frequency offset. The third stage is for observing the trailing edge of the curve if it was not already observed in stage two. Upon detection of receipt of the first pilot, a second pilot can subsequently be employed to acquire fine symbol timing.

Abstract: Frequency error estimation and frame synchronization are performed at a receiver in an OFDM system based on a metric that is indicative of detected pilot power. The metric may be defined based on cross-correlation between two received symbols obtained in two OFDM symbol periods. For frequency error estimation, a metric value is computed for each of multiple hypothesized frequency errors. The hypothesized frequency error for the metric value with the largest magnitude is provided as the estimated frequency error. For frame synchronization, a correlation value is obtained for each OFDM symbol period by correlating metric values obtained for NC (e.g., most recent) OFDM symbol periods with NC expected values. The expected values are computed in a manner consistent with the manner in which the metric values are computed. Peak detection is performed on the correlation values obtained for different OFDM symbol periods to determine frame synchronization.

Abstract: A detection framework that matches anatomical structures using appearance and shape is disclosed. A training set of images are used in which object shapes or structures are annotated in the images. A second training set of images represents negative examples for such shapes and structures, i.e., images containing no such objects or structures. A classification algorithm trained on the training sets is used to detect a structure at its location. The structure is matched to a counterpart in the training set that can provide details about the structure's shape and appearance.

Abstract: A novel method and apparatus for efficiently coding and decoding data in a data transmission system is described. A concatenated coding scheme is presented that is easily implemented, and that provides acceptable coding performance characteristics for use in data transmission systems. The inventive concatenated channel coding technique is well suited for small or variable size packet data transmission systems. The technique may also be adapted for use in a continuous mode data transmission system. The method and apparatus reduces the complexity, cost, size and power consumption typically associated with the prior art channel coding methods and apparatuses, while still achieving acceptable coding performance. The present invention advantageously performs concatenated channel coding without the necessity of a symbol interleaver. In addition, the present invention is simple to implement and thereby consumes much less space and power that do the prior art approaches.

Abstract: In an OFDM system, a transmitter broadcasts a first TDM pilot on a first set of subbands followed by a second TDM pilot on a second set of subbands in each frame. The subbands in each set are selected from among N total subbands such that (1) an OFDM symbol for the first TDM pilot contains at least S1 identical pilot-1 sequences of length L1 and (2) an OFDM symbol for the second TDM pilot contains at least S2 identical pilot-2 sequences of length L2, where L2>L1, S1·L1=N, and S2·L2=N. The transmitter may also broadcast an FDM pilot. A receiver processes the first TDM pilot to obtain frame timing (e.g., by performing correlation between different pilot-1 sequences) and further processes the second TDM pilot to obtain symbol timing (e.g., by detecting for the start of a channel impulse response estimate derived from the second TDM pilot).

Abstract: CAD (computer-aided diagnosis) systems and applications for cardiac imaging are provided, which implement methods to automatically extract and analyze features from a collection of patient information (including image data and/or non-image data) of a subject patient, to provide decision support for various aspects of physician workflow including, for example, automated assessment of regional myocardial function through wall motion analysis, automated diagnosis of heart diseases and conditions such as cardiomyopathy, coronary artery disease and other heart-related medical conditions, and other automated decision support functions. The CAD systems implement machine-learning techniques that use a set of training data obtained (learned) from a database of labeled patient cases in one or more relevant clinical domains and/or expert interpretations of such data to enable the CAD systems to “learn” to analyze patient data and make proper diagnostic assessments and decisions for assisting physician workflow.

Abstract: A system and method for detecting a shape in an image are provided. The method comprises: constructing a deformable model from an image; deforming the deformable model to remove an undesired shape in a portion of the image; computing properties of the deformed model to enable detection of a desired shape in the portion of the image; and detecting the desired shape based on the computed properties.

Abstract: The present invention relates to a system of modeling a three dimensional target object which is represented by a plurality of cross-sectional images in order to provide a representative corresponding three dimensional model. The invention selects an initial model from a plurality of available initial models. This selection involves identifying an initial model based on physical similarity to the target object and then superimposing an initial model upon the target object, for each of the plurality of cross-sectional images. A determination is then made of an intersection contour of the initial model and a cross-sectional image of the target object and the determined intersection contour is refined in order to more closely delineate the target object. By sub-sampling points which represent the refined determined intersection contour, the invention obtains a sub-sampled contour dataset.

Abstract: A system and method for providing decision support to a physician during a medical examination is disclosed. Data is received from a sensor representing a particular medical measurement. The received data includes image data. The received data and context data is analyzed with respect to one or more sets of training models. Probability values for the particular medical measurement and other measurements to be taken are derived based on the analysis and based on identified classes. The received image data is compared with training images. Distance values are determined between the received image data and the training images, and the training images are associated with the identified classes. Absolute value feature sensitivity scores are derived for the particular medical measurement and other measurements to be taken based on the analysis. The probability values, distance values and absolute value feature sensitivity scores are outputted to the user.

Abstract: A method for registration of magnetic resonance (MR) and computed topography (CT) images, in accordance with the present invention includes providing MR images having a region of interest delineated by first contours and providing CT images having the region of interest delineated by second contours. A pre-existing model of the region of interest is also provided. The pre-existing model is fit to the first contours or the second contours to provide a first resultant model. The first resultant model is then copied to provide a copied model. The copied model is fit to the other of the first contours and the second contours to provide a second resultant model. By rotating and translating the first resultant model and the second resultant model, the first resultant model and the second resultant model are registered.

Abstract: The present invention relates to a system of modeling a three dimensional target object which is represented by a plurality of cross-sectional images in order to provide a representative corresponding three dimensional model. The invention selects an initial model from a plurality of available initial models. This selection involves identifying an initial model based on physical similarity to the target object and then superimposing an initial model upon the target object, for each of the plurality of cross-sectional images. A determination is then made of an intersection contour of the initial model and a cross-sectional image of the target object and the determined intersection contour is refined in order to more closely delineate the target object. By sub-sampling points which represent the refined determined intersection contour, the invention obtains a sub-sampled contour dataset.

Abstract: A technique of tracking an object of interest in a sequence of images using active polyline contours. An image processor converts a sequence of images into digital image data related to light intensity at the pixels of each image. A computer stores the digital image data and forms an initial polyline that substantially outlines an edge of the object in a first image. The computer forms input polylines for each of the subsequent images which substantially outline the edge in the corresponding images and are derived from the optimal polyline of each previous such image. The computer processes the digital image data, performing a graph exploration procedure that starts with the initial polyline in the first image and the input polylines in the subsequent images. The graph exploration procedure searches polylines in a predefined search space to find the corresponding optimal polylines.

Abstract: A method of modeling a structure comprises the steps of initializing a parametric component of a hybrid model from a volumetric image, the volumetric image comprising image planes, creating starting points for two dimensional segmentations at intersections between the parametric component and the image planes, segmenting a boundary of the structure by applying active contours, sampling the active contours to create a dataset and parametrically and locally fitting the hybrid model to the dataset to represent the structure.

Abstract: A technique of displaying a segment of a coronary artery in a stabilized cineangiogram. A computer system receives a sequence of images of a conventional cineangiogram. A user displays a first image on a monitor and selects a point on an arterial segment. The computer system invokes an image tracking procedure that employs active optimal polyline contours to locate the arterial segment and a fixed point in each of the image frames of the conventional cineangiogram. The computer system produces a stabilized cineangiogram by translating the images to place the arterial segment in substantially the same viewing location in each one of the image frames.

Abstract: A system for analyzing motion contains an overall model that includes local deformations and a scaleable default model having a global component and parametric offsets. The offsets provide two features. First, they help to form an expected model shape which facilitates appropriate model data correspondences. Second, they scale with the global component to maintain the expected shape even in the presence of large global deformations. The system is applied to the recovery of a 3-D object from a volunteer dataset of tagged images.

Abstract: Methods and apparatus for variable-rate down-sampling filters for discrete-time sampled systems using a fixed sampling rate are disclosed. The Variable Rate Down-Sampling Filter allows a continuous range of sample rates to be derived from input samples at a fixed rate. The output rate does not have to be related to the fixed input rate in any integral or rational way, and in fact, the output rate can vary in time such as will occur when tracking a signal received from a station using a different timebase. A fixed sampling rate at the A/D Converter greatly simplifies the design of the analog front end. A single anti-aliasing filter can be designed and precisely matched to the fixed sampling rate. Used with a frequency-modulated numerically controlled oscillator (NCO), the Down-Sampling Filter keeps the entire frequency-synthesis and time-tracking loop in the digital domain. The need for an analog time-tracking loop to adjust the sampling instant at the A/D converter is eliminated.

Abstract: A system for recovering cardiac motion includes an overall model, a geodesic-like prismoidal tessellation of the model and constant volume constraints. The overall model includes local deformations and a scaleable default model having a global component and parametric offsets. The offsets provide two features. First, they help to form an expected model shape which facilitates appropriate model data correspondences. Second, they scale with the global component to maintain the expected shape even in the presence of large global deformations. The system is applied to the recovery of 3-D cardiac motion from a volunteer dataset of tagged-MR images.

Abstract: The model of the present invention incorporates incompressibility constraints to infer 3-D motion. Discrete, projected 2-D motion information from two different views of an object are input into the system. A model is realized via the tessellation component, and the material property of incompressibility is imposed on model movement. The output of the system is a continuous 3-D motion model which has interpolated the projected 2-D data.

Abstract: A Reed-Solomon decoder and a decoding algorithm executed by the decoder are disclosed. The decoder includes a syndrome computer and a syndrome processor. The syndrome computer is a pipelined functional unit for computing syndromes from a received codeword and storing erasure location members as flagged by an Erasure Flag signal. The syndrome processor includes a pipelined functional unit and a Chien search circuit for receiving from said syndrome computer the computed syndromes, erasure locations, and number of erasures and computing erasure locator polynomial, modified syndrome polynomial, error locator and error evaluator polynomials, error-erasure locator polynomial, and error value at an error location at each error location found by the Chien search circuit.