Abstract: The invention provides a method for tracking characteristics of an object, the method including acquiring image data of a first image of the object to be tracked, as viewed by an imaging unit; storing data representing a selected portion of the first image, thus forming a first template having first defined dimensions; storing data representing at least one different portion of the first image, thus forming a second template having second template dimensions; acquiring image data of a second image of the object to be tracked, as viewed by the imaging unit; defining a search area comprising portions of the second image; defining a first gate in the search area, the gate possessing dimensions identical to those of the first template, thus forming a first template/gate pair; defining at least one second gate in the search area, the at least one second gate possessing dimensions identical to those of the second template, thus forming at least one second template/gate pair; the template/gate pairs being stored in

Abstract: A method for determining a lower-bound quantity per unit volume of a physical property associated with a body, the property being susceptible to measurement in a plurality of directions. In general, the method comprises the steps of scanning a volume of interest in a predetermined number of directions so as to derive for each direction an area having a plurality of projections thereon each representing a cumulative value of said property within the volume of interest along a respective one of the directions, and determining an estimated volume of the body as the intersection of all volume elements bounded by the derived areas. For each area the sum of all the projections are compared and correction is applied as required so as to remove any disparity between the sums so as to produce a uniform sum in each of the directions. The lower-bound quantity per unit volume of the property of the body is then calculated as the quotient of the uniform sum divided by the estimated volume.

Abstract: An improved image intensifier system including an image intensifier, a camera operative to receive the output of the image intensifier and to transmit a signal including a multiplicity of pixel sets, a television monitor operative to receive the television signal from the camera and to translate such a signal into an image, and apparatus for reducing spikes in an image by detecting the spikes in a given pixel set, henceforth called the first pixel set, and replacing the spikes with information derived from a different pixel set, henceforth called the second pixel set.

Abstract: A reordering system for reducing respiratory artifacts in magnetic resonance images. The respiration cycle of the patient is measured and divided into N exclusive intervals. A different encoding amplitude is assigned to each interval in a first look-up table (LUT). The encoding pulses are selected by the first LUT responsive to measured respitory intervals. After M encoding pulses have been selected, a new LUT is constructed from the unused encoding pulse amplitudes using a new number (N-M) intervals. The new LUT is then used for another given number of encoding pulses. Other new LUT's are constructed after given numbers of encoding pulses are used until all encoding pulses are used.

Abstract: Means and methods for correcting the loss of contrast caused by modulation transfer function (MTF) effects in imaging. Images of small objects are enhanced without adversely affecting large object images. A homogeneous background is provided and image contrast is obtained with total MTF effects. The scale of the determined image contrast is manipulated to cause the contrast to approximate an ideal contrast not affected by the MTF contrast reduction.

Abstract: A method and system for using magnetic resonance imaging (MRI) to acquire separate data contributions from first and second spectral components by causing a 90 degree phase difference between the data of said components in a first of at least two echoes and using the two echoes to determine the approximate .DELTA..phi. delay due to inhomogeneity, determining linear phase delay .beta. and using .DELTA..phi. and .beta. in the calculation of the separated data contributions of each of the spectral components.

Abstract: Data selection method and system using a plurality of multi-dimensional windows wherein two parameters of ECG signals are tested for determining whether the imaging data received simultaneously with the ECG signal is to be accepted. The plurality of windows provides a capability to gate and to sort imaging data based on the passage of associated ECG signals through each of the plurality of windows with different parameters. Thus images can be reconstructed for a populations of abnormally short or long heart cycles from a common data pool.

Abstract: A data compression system for use in processing diagnostic image data which uses a predictor to predict future data. The actual data is subtracted from the predicted value to obtain data related difference values. The difference values are coded by coding the most prevalent difference by a code other than the least bit code but further coding the most prevalent number by string length coding, with the most common being the coded with a least bit code, and also coding the next most common difference with a least bit code and the subsequent most prevalent differences with sequential least bit codes to provide compression ratios of over 3:1. A procedure for finding the best predictor in noisy data is provided.

Abstract: A continuous phase magnetic field map is provided by dividing the field map of elements into regions; determining discontinuities in the regions and adding a constant modulo 2.pi. to the phase values of each element of the region which results in a minimum difference between adjacent elements of the region. Then similarly joining the continuous regions to form continuous sections and the continuous sections to form continuous zones until substantially continuous phase magnetic field maps are obtained.

Abstract: A data compression-expansion (decrease-increase) method for improving the signal-to-noise ratio of compressed-expanded data while retaining the fidelity of the original data comprises the steps of using a filter that can be separated into a smoothing portion and an enhancing portion. The selected filter is separated into the two portions: a first portion for smoothing prior to decreasing the data, and a second portion for enhancing after increasing the data whereby the filter has the maximal effect of decreasing noise while having a minimal effect on the data.

Abstract: A method of quantitatively determining the stenosis of the blood vessel using a digital subtraction angiographic image of the blood vessel. The method includes obtaining numbers proportional to the cross sectional areas of the blood vessel at stenosis portions and normal portions by obtaining density profiles less residual background from the images at those portions.

Abstract: Image enhancement accomplished by filtering using filters optimally adjusted to system parameters to enhance long edges, attenuate noise and "points" so that the long-edge data normally buried in noise is available and to further enable using low-frequency data.

Abstract: A method and system for determining the movement of an object between different images of the same object; where the movement is defined by a vector value and the vector value is used to correct for misregistration between the different images.

Abstract: An image optimizing method for reducing statistical noise in medical diagnostic images constructed from data obtained by the interaction of radiation and detectors. The radiation occurs in a random manner such that the data obtained at specific locations on the detectors are only estimates of "true" values of the data at the locations. The method includes the steps of fitting a surface to each of the locations; the surface is defined by the measured values of the location and neighboring locations. The fitted surface is used to determine new values for each of the locations. It has been found that the new values are closer to the "true" values of the data at the locations than were the measured values.

Abstract: A data compression system for use in processing diagnostic image data which combines delta modulation with coding the most prevelant difference by a code other than a least bit code but coding the most prevalent number of strings with a least bit code and also coding the next most common differences with a least bit code and subsequent most common differences with sequentrial least bit codes to provide compression ratios of over 3:1.

Abstract: An imaging system that acquires and stores every other line to be used in a display image and interpolates the stored lines to obtain the lines between the stored lines for display purposes.

Abstract: A misregistration correction system that corrects for artifacts generated by the movement of a subject being imaged during the interval between temporally separated images. The system reduces the effects of secondary characteristics on the determination of a vector between a point on a first image and a point on a second image, which vector delineates the motion of the subject.

Abstract: An improved ECG system for on-line analysis of the signals received from exercise ECGs whereby the signals from at least a pair of electrodes are differentiated and compared to find maximum slopes of the same sign occuring at the same time, which characteristics are deemed indicative of "R" waves.

Abstract: A pseudo correlation system and method for determining matches between data defined shapes and templates by obtaining a pseudo correlation value without a successivity of multiplications or determining square roots.

Abstract: Improved diagnostic imaging methods and systems for automatically controlling variable parameters used when translating detected radiation intensities caused by radiation that has passed through an object and impinged on a detector to fixed values for display images by determining the maximum and minimum intensities at the impinged on detector locations and adjusting the parameters as functions of the said maximum and minimum intensities.