Abstract: Pixel data forming an image is clustered into groups of data of similar color. Pixels of approximately the same color form one cluster. A vigilance parameter determines how many clusters are derived and how wide a range of colors are included in a cluster. The process for allocating input vectors into clusters is based upon a minimum distance measure to multiple prototype vectors. A given image frame is allocated into clusters in an iterative process. A subset of clusters from an initial image frame are treated as featured clusters. The featured clusters correspond object(s). To track the object, input vectors in subsequent frames are tested to determine whether they correspond to a featured cluster. A scene change is detected when more than a prescribed number of prototype vectors have changed by more than a predetermined amount.

Abstract: A template is analyzed to determine step sizes for searching within a search area. The template is analyzed by first padding the template with data points to increase its size. Cross-correlation between the padded template and the original template leads to identification of an effective step size along multiple axes. Step sizes for each of a horizontal, vertical and a third axis are derived. Third axis step sizes may correspond to rotation, scaling factor, subsampling factor, linear distance, time or frequency. Windows of the search area, selected based on the step sizes, then are tested in a fast search by correlating the template to selected windows to derive correlation coefficients. Any tested window which has a correlation coefficient exceeding a given value is a potential match for the template and is subject to a refined stage of comparison.

Abstract: Transrectal ultrasound is used for accurate planning and targeting of placement of radioactive seeds by needles into the prostate in transperineal prostate brachytherapy. The pubic arch formed by the union of the pelvic bones is a potential barrier to passage of the needles containing the radioactive seeds. An initial image of the pubic arch is also provided by transrectal ultrasound, in addition to a transverse cross-sectional image of the prostate. The initial image of the pubic arch is processed using a technique to selectively enhance the contrast of the linear features of the edge of the ultrasound image. The enhanced image is then thresholded via the use of a percentile thresholding technique and then a curve modeling the shape of the pubic arch is fitted against the thresholded, enhanced image to produce a processed image of the pubic arch. This is then overlaid with the image of the prostate and a determination made as to pubic arch interference.

Abstract: A method for generating color Doppler images is implemented in real time using digital processing steps implemented on multi-purpose microprocessors. Processing is reduced by estimating velocity only when a tissue threshold decision for a given sample indicates that the sample is not tissue. Arc tangent calculations in the velocity estimation are performed using simplified look-up tables without sacrificing accuracy. One look-up table is lineraly quantized. A second is nonlinearly quantized.

Abstract: An ultrasound system automatically measures fetal head size from ultrasound images. An ultrasound image of the fetal head is detected. A radial maxima point is identified on each of a plurality of radii extending from a substantially common vertex point within the fetal head image. Each radial maxima point corresponds to an ultrasound sample along its corresponding radius, and has a maximum ultrasound echo strength. Outlier points are removed and the curve filtered to derive an initial fetal head boundary. An inner fetal head boundary and outer fetal head boundary are derived from the initial fetal head boundary and a predetermined fetal skull thickness, and fetal head size is computed from the inner fetal head boundary and the outer fetal head boundary. Processing is allocated among multiprocessors and performed in pipeline fashion to enable real-time interactive imaging and measuring.

Abstract: A 3D image is generated in real-time on an ultrasound medical imaging system which performs acquisition, volume reconstruction, and image visualization tasks using multiple processors. The acquisition task includes deriving position and orientation indicators for each gathered image frame. Volume reconstruction includes defining a reference coordinate system within which each image frame in a sequence of image frames is registered. The reference coordinate system is the coordinate system for a 3D volume encompassing the image planes to be used in the 3D image. The first image frame is used to define the reference coordinate system. As each image plane is registered, a 2D projection of the incremental volume is displayed. A shear-warp factorization process is used to derive a 2D projection for a rotated volume. A viewing transformation matrix is factorized into a 3D shear which is parallel to slices of the reference volume. A 2D warp then is implemented to produce the projection of the rotated volume.

Abstract: A method and apparatus for defining, in a computing system, the bit size of an instruction to be executed by a processing unit. Instructions are realized in the form of a plurality of memory location devices. At least one of said memory location devices, in a predetermined position, is established as a MODE bit. The MODE bit assumes a first value indicative of parallel instruction execution and assumes a second value indicative of non-parallel instruction execution.

Abstract: An ultrasound system automatically measures fetal head size from ultrasound images. An ultrasound image of the fetal head is detected. A radial maxima point is identified on each of a plurality of radii extending from a substantially common vertex point within the fetal head image. Each radial maxima point corresponds to an ultrasound sample along its corresponding radius, and has a maximum ultrasound echo strength. A first curve is defined from the radial maxima points. The remaining unfiltered radial maxima points are fit to a second curve, and the second curve is the detected curved boundary. The detected curve boundary is modified to define an initial fetal head boundary. An inner fetal head boundary and outer fetal head boundary are derived from the initial fetal head boundary and a predetermined fetal skull thickness, and fetal head size is computed from the inner fetal head boundary and the outer fetal head boundary.

Abstract: A Central Processing Unit (CPU) debugging device and method therefor is disclosed which provides data entering and interrogating devices which will temporarily stop all CPU execution when desired by a user and allow a non-destructive intrusion into the contents of any of the CPU internal registers, state bits, and cache and local memories. After the desired CPU contents have been reviewed and subsequently altered or maintained by a user, the CPU execution may be resumed.

Abstract: A scan conversion method is implemented to achieve real-time scan conversion at video rates. Scan conversion tasks include vector point identification processing, distance derivation processing and interpolation processing. An active image area is defined in response to user inputs. For a given set of user adjustments there is a fixed active image area of the display screen. In addition, there is a fixed positional relationship between output pixel locations of the active image and corresponding input vector points of the active image. Whenever the user makes adjustments, these relationships change becoming fixed again until another user-initiated change. Whenever the relationships change, vector identification processing and distance derivation processing is re-done to define these relationships. Interpolation processing is performed each frame only for output pixels within the active image area. The active image area is divided into groups of output pixels.

Abstract: A method for selectively controlling the operation of a computer system so that the computer system is selectively caused to execute instructions of a first predetermined bit length or instructions of a second predetermined bit length. The method comprises the preliminary steps of storing instruction data in a set of EVEN instruction storage locations; storing instruction data in a set of ODD instruction locations; establishing an EVEN execution pointer; and establishing an ODD execution pointer. At a first given time, either the EVEN execution pointer is incremented by a predetermined COUNT or the ODD execution pointer is incremented by the predetermined COUNT; but both pointers are not simultaneously incremented by the COUNT. The method causes an instruction to be executed, which instruction was stored entirely in either an EVEN instruction location or entirely in an ODD instruction location.

Abstract: An ultrasound signal processing apparatus provides a programmable platform for various clinical ultrasound applications. The apparatus is part of an ultrasound medical diagnostic imaging system. Data is processed in real-time, near real-time or in delayed playback. In one embodiment a pair of multi-processors are coupled to shared memory via a cross-bar switch. System control data is input via a VME interface. Ultrasound data is input via frame buffers. A first multi-processor manages vector data transfers and scan-converted data acquisitions. A second multi-processor manages video data output. The two multi-processors split signal processing tasks. In various configurations the apparatus executes vector processing, scan conversion, image processing and/or video processing tasks.

Abstract: The present invention provides a unified image and graphics processing system that provides both image and graphics processing at high speeds. The system includes a parallel vector processing unit, a graphics subsystem, a shared memory and a set of high-speed data buses for connecting all of the other components. Generally, the parallel vector processing unit includes a series of vector processors. Each processor includes a vector address generator for efficient generation of memory addresses for regular address sequences. In order to synchronize and control the vector processors' accesses to shared memory, the parallel vector processing unit includes shared memory access logic. The logic is incorporated into each vector processor. The graphics subsystem includes a series of polygon processors in a pipelined configuration. Each processor is connected in the pipeline by a first-in-first-out (FIFO) buffer for passing data results.

Abstract: An image computing system providing at least two display modes and including a set of image coprocessors is disclosed. The system converts image data into signals representing pixel characteristics. The signals can be displayed via a video display device. In a first display mode, pixel characteristic signals are generated for related image planes of a single image by a series of display generating devices and each signal is selected from a separate display generating device. The selected signals are output to a video display device. In a second display mode, pixel characteristic signals for an independent image plane are selected from a single display generating device. The signals are output to a video display device. In this mode, each display generating device converts image data for an independent image plane. In this manner, the system provides single or multiple image display modes. The image coprocessors provide efficient image processing of the image data.