Abstract: A system for monitoring alignment of a signal lamp includes at least one sensor and threshold detection circuitry. The sensor is positioned about the signal lamp and is configured to measure at least one of azimuthal and elevational movement of the signal lamp and generate an electrical signal. The threshold detection circuitry is configured to receive signals representative of the azimuthal and elevational movement of the signal lamp from the sensor. The threshold detection circuitry determine a change in alignment of the signal lamp according to at least one of the azimuthal movement signals and the elevational movement signals.

Abstract: A method for inspecting a component includes exciting a number of transducers forming an array to produce an ultrasonic transmission beam (beam) focused into the component. The array and the component are separated by a standoff. A number of echo signals are generated using the transducers, and the echo signals are processed in a number of channels. The processing includes both dynamical focus and providing a dynamic aperture on receive, both of which compensate for refraction of the beam at the component/standoff interface. A single-turn inspection method includes: (a) positioning the array facing the component, (b) exciting the transducers, (c) generating a number of echo signals, (d) changing the relative angular orientation of the array and the component around an axis and repeating steps (b) and (c), and (e) processing the echo signals to form at least one processed echo signal.

Abstract: A method for inspecting a component includes exciting a number of transducers forming an array to produce an ultrasonic transmission beam (beam) focused into the component. The array and the component are separated by a standoff. A number of echo signals are generated using the transducers, and the echo signals are processed in a number of channels. The processing includes both dynamical focus and providing a dynamic aperture on receive, both of which compensate for refraction of the beam at the component/standoff interface. A single-turn inspection method includes: (a) positioning the array facing the component, (b) exciting the transducers, (c) generating a number of echo signals, (d) changing the relative angular orientation of the array and the component around an axis and repeating steps (b) and (c), and (e) processing the echo signals to form at least one processed echo signal.

Abstract: A three-dimensional projection image representing a projection of a data volume at a predetermined orientation, three cut plane images representing respective mutually orthogonal planar cuts through the data volume, a graphical representation of the data volume at that orientation and graphical representations of the cut planes are displayed in spaced relationship. Each of the cut planes has a respective positional relationship to the data volume graphic that corresponds to the positional relationship of the respective cut plane to the data volume. The graphical representations are displayed in different colors. Any one of the four images can be active in the sense that images are reconstructed in real-time as a trackball is moved. Which of the four images is active is indicated by displaying the corresponding graphical representation in a color denoting the active state.

Abstract: The axis of rotational transducer array scans, because of imperfect transducer array assembly, may have two orthogonal offsets relative to the geometric center of the transducer array. Without knowledge of these offsets, it is not possible to convert rotational transducer scan data into a rectilinear (Euclidean) coordinate system, as is necessary for three-dimensional processing. Using spatial coherency between appropriate scan lines in different rotational transducer scans, the horizontal and vertical rotational offsets are calculated. These offsets are then utilized in converting the data to a rectilinear coordinate system for three-dimensional processing.

Abstract: In performing three-dimensional flow imaging using coded excitation and wall filtering, a coded sequence of broadband pulses (centered at a fundamental frequency) is transmitted multiple times to a particular transmit focal position. On receive, the receive signals acquired for each firing are compressed and bandpass filtered to isolate a compressed pulse centered at the fundamental frequency. The compressed and isolated signals are then wall filtered to extract the flow imaging data. This process is repeated for a multiplicity of transmit focal positions in each of a multiplicity of scanning planes to acquire a volume of flow imaging data. Volume rendered images are then produced which allow the user to view the data volume from any angle. In addition, the data volume may be reformatted to produce two-dimensional images of arbitrary cut planes through the data volume.

Abstract: In three-dimensional imaging of ultrasound data, speckle artifact data are reduced before the acquired data from a volume of interest are projected onto an image plane. A master controller performs an algorithm that iteratively morphologically filters the pixel data in a volume of interest and then iteratively projects the morphologically filtered data onto a plurality of rotated image planes using a ray-casting technique. Morphological filtering is performed by stepping a seven-point kernel through a source data volume of pixel data. The kernel, made up of a central pixel value and the six pixel values adjacent to the central pixel value, is stepped through the entire source data volume. The morphological filtering operation includes at least one erosion step, which removes speckle, followed by an equal number of dilation steps, which restore the imaging data.

Abstract: A method and an apparatus for segmenting three-dimensional projected velocity images by limiting the volume of velocity data projected onto the imaging planes. If the volume of interest contains flowing blood, i.e., an artery or vein, the Doppler shift present in the ultrasound reflected from the flowing blood can be detected and then used to limit the amount of velocity data which is projected. Only pixels having velocity values within a predetermined range are projected onto the imaging plane.

Abstract: A method and apparatus for calculating the inter-slice spacing in a data volume and registering the slices of that volume using SAD calculations. The resulting transformed data volume is then three-dimensionally reconstructed using a projection technique. If during scanning the probe is translated in the Z direction and at the same time is shifted in the X and/or Y direction, the SAD value will be artificially high. By translating two adjacent images with respect to each other in the X direction and then in the Y direction, and searching for the minimum SAD value, the amount of shift in the X and/or Y direction can be determined and that shift can then be removed. Also by rotating two slices with respect to each other and looking for a minimum SAD value, rotational motion of the probe during scanning can be removed.

Abstract: A three-dimensional image of flowing fluid or moving tissue using velocity or power Doppler data is displayed by using an ultrasound scanner that collects velocity or power data in a cine memory to form a volume of pixel data. Average or median pixel values are projected on an image plane by casting rays through the data volume. As the ray passes through each scan plane, a data value is assigned to the ray at that point. At each scan plane, the assigned pixel data value is tested to see if it exceeds a noise threshold. For a given ray, pixel data values above the detection threshold are accumulated until a pixel data value falls below the detection threshold. A minimum number of pixel data values exceeding the threshold are required for each ray before the average of the accumulated values is processed and/or the median value is selected. When all pixels along a given ray have been tested, the projection is complete and the average or median projection is then displayed.

Abstract: In performing for three-dimensional ultrasound imaging of an object from any angle relative to the plane of acquisition, a human body is scanned to acquire multiple images forming a data volume. The system computer generates a multiplicity of reformatted slices through the data volume and parallel to the imaging plane. For each projected pixel, a ray is cast through the reformatted slices onto the imaging plane. For each pixel along the ray, the accumulated intensity is calculated as a function of the pixel and opacity values for the pixel being processed, the accumulated intensity calculated at the preceding pixel the remaining opacity for the subsequent pixels. The final accumulated intensity for each ray is obtained when the remaining opacity reaches a predetermined minimum. The accumulated intensities for all cast rays form the projected image.

Abstract: A method and an apparatus for displaying three-dimensional images of ultrasound data having improved segmentation. This is accomplished by harmonic imaging. There are two types of harmonic imaging: (1) imaging of harmonics returned from contrast agents injected into the fluid; and (2) naturally occurring harmonics, generally referred to as "tissue harmonics". An ultrasound transducer array is controlled to transmit a beam formed by ultrasound pulses having a transmit center frequency and focused at a desired sample volume containing contrast agents. In the receive mode, the receiver forms the echoes returned at a multiple or sub-multiple of the transmit center frequency into a beam-summed receive signal. This process is repeated for each sample volume in each one of a multiplicity of scan planes. After filtering out the undesired frequencies in the receive signal, i.e.

Abstract: A method and an apparatus for improving the contrast of the displayed image data in a B-mode ultrasound imaging system. An adaptive gray mapping is based on the actual raw imaging data instead of assumptions about that raw data. The user specifies a region of the image (or the entire image) with a graphical region-of-interest (ROI) marker. When prompted by the user, a software program in the master controller analyzes the raw data within the ROI and constructs a new gray map based upon the analyzed data. This mapping can be created by transforming an old gray map or by generating a new gray map. This new gray map is then used by the ultrasound system during imaging. Optimum contrast is achieved by automatically adjusting the brightness and contrast levels of the image based on the values of the raw data.

Abstract: A method and an apparatus for three-dimensional ultrasound imaging of a needle-like instrument, such as a biopsy needle, inserted in a human body. The instrument is visualized by transmitting ultrasound beams toward the instrument and then detecting the echo signals using a linear array of transducer elements. The problem of ultrasound being reflected from a biopsy needle in a direction away from the transducer array is solved by steering the transmitted ultrasound beams to increase the angle at which the beams impinge upon the biopsy needle. Ideally the ultrasound beams are perpendicular to the biopsy needle. This increases the system's sensitivity to the needle because the reflections from the needle are directed closer to the transducer array. This can be accomplished using either the B mode or the color flow mode of an ultrasound imaging system.

Abstract: A method and an apparatus for tracking scan plane motion in free-hand three-dimensional ultrasound scanning using adaptive speckle correlation. The method employs a correlation index which adapts to different display dynamic range and post-processing filters. The method may include the following steps: choosing a kernel within each frame image for correlation calculations; rejecting duplicate image frames; measuring the degree of correlation between successive image frames; rejecting correlation estimates which may be associated with hand jitter and other artifacts; and computing the average frame-to-frame (i.e., interslice) spacing based on the average correlation estimate. This image-based motion tracking technique enables three-dimensional reconstruction with good geometric fidelity, without use of any external position-sensing device.

Abstract: A method and an apparatus for automatically adjusting the contrast of a projected ultrasound image. An ultrasound scanner collects B-mode images in a cine memory, i.e., for a multiplicity of slices. The data from a respective region of interest for each slice is sent to a master controller, such data forming a volume of interest. The master controller performs an algorithm that iteratively projects the pixel intensity data in the volume of interest onto a plurality of rotated image planes using a ray-casting technique. Before the projected images are stored in cine memory, the contrast of the pixel intensity data making up those projected images is adjusted by the master controller using a one-to-one mapping of unadjusted pixel intensity data into adjusted pixel intensity data. The mapping is generated by the master controller based on the pixel intensity data of either a source frame or a projected image. The contrast adjustment mapping is applied to each projected image.

Abstract: A method and an apparatus for allowing the operator of an ultrasound imaging system to switch between two-dimensional slices and three-dimensional projections in such a way that it is easy for the operator to visualize the relationship of the two-dimensional slice to the three-dimensional anatomy. In a "volume rotate" mode, the display screen displays an orientation box along with a three-dimensional projected image generated from a defined data volume. The orientation box provides a visual indication of the shape and orientation of that defined data volume. In a "cut plane" mode, a movable polygon representing a selected two-dimensional slice is displayed inside a stationary orientation box. The polygon provides a visual indication of the orientation and position of the slice relative to the defined data volume. In a "cut plane rotate" mode, a stationary polygon representing a selected two-dimensional slice is displayed inside a rotatable orientation box.

Abstract: Methods and apparatus for generating test vectors for use in testing ASIC designs at both the functional and circuit levels, and for comparing the results of functional level and circuit level tests, employ a set of software tools to facilitate generating test vectors and to compare results of simulation at the functional level with results of simulation at the synthesized circuit level. The software tool set includes a preprocessor program which reads source files and produces skeleton test vector files, a compiler program for compiling the test vector files, and an output comparison program for comparing functional level test results with circuit simulation level test results.

Abstract: A method and an apparatus for three-dimensional imaging of ultrasound data by combining projections of intensity data with projections of velocity or power data from a volume of interest. The apparatus is an ultrasound scanner which collects B-mode or color flow images in a cine memory, i.e., for a multiplicity of slices. The data from a respective region of interest for each slice is sent to a master controller, such data forming a volume of interest. The master controller performs an algorithm that projects the data in the volume of interest on a plurality of rotated image planes using a ray-casting technique. The combined intensity and velocity or power data for each projection is stored in a separate frame in the cine memory. These reconstructed frames are then displayed selectively by the system operator.

Abstract: A method and an apparatus for improving the segmentation of a three-dimensional B-mode image by limiting the volume of pixel intensity data projected onto the imaging planes. If the volume of interest contains moving ultrasound scatterers, e.g., blood flowing in an artery or vein, the Doppler shift present in the ultrasound reflected from the flowing blood can be detected and then used to limit the amount of pixel data which is projected. The velocity or power data is used to identify those intensity values to be projected onto the imaging plane. This is accomplished by locating a reference data volume of pixels for which the velocity or power value is non-zero and then defining a source data volume which is essentially a function of that reference data volume. The reference data volume comprises pixels acquired from echo return signals reflected by the moving ultrasound scatterers.