Abstract: A method is provided for determining a calibration relationship between a reference frame of motion of an object and a reference frame of a camera that generates images of the object. The method includes the steps of coupling a target to an object and placing the object at each of plural locations and orientations that are known with respect to the motion reference frame of the object. The location of the target(s) with respect to the object need not be known. An image of the object and target is generated while the object is at each of those locations/orientations. From each those images, the method determines the location/orientation of the target with respect to the reference frame of the camera.

Abstract: The invention provides methods and apparatus for machine vision illumination by moving a non-diffuse light beam over selected points on the object so that each is illuminated at substantially the same angle by multiple rays during acquisition of an image frame. An apparatus for illuminating an object to facilitate its being imaged by an image acquisition device, e.g., a camera, includes a radiation source that generates and transmits to a region of the a non-diffuse beam of imaging radiation having a non-point cross-section. A dithering element moves the beam so that at least a region of the object is illuminated at substantially the same angle by multiple rays during an image acquisition period.

Abstract: Machine vision methods for inspection of semiconductor die surfaces include the steps of generating a first image of the die surface, generating a second image of the die surface and any defect thereon, and subtracting the second image from the first image. The methods are characterized in that the second image is generated such that subtraction of it from the first image emphasizes the defect with respect to the die surface.

Abstract: The invention provides a method of testing a machine vision system of the type that inspects a feature (e.g., an electronic component) using object-oriented constructs that instantiate an inspection object from an inspection class that is associated with a type of the feature (e.g., the rectilinear component) and that invoke a method member of that object to inspect the feature to determine its characteristics (e.g., position, angular orientation, and shape conformance). The method of the invention includes the steps of instantiating a test object from a test class that corresponds to the inspection class, invoking a method member of that test object to generate one or more test images representing the feature, inspecting the test images to determine characteristics of the features therein, and reporting results of those inspections.

Abstract: A method for determining extrema of an object with respect to a reference frame that is rotated in comparison to that of the image and the equipment that acquired it is characterized by the steps of taking a first projection of the object with respect to an axis of a coordinaate system that is rotated with respect to the reference frame of the acquisition equipment, identifying in that projection locations representing extrema of the object, and outputting those locations as indicative of the extrema with respect to the axis.

Abstract: A system for edge-based image histogram analysis permits identification of predominant characteristics of edges in an image. The system includes an edge detector that generates an edge magnitude image having a plurality of edge magnitude values based on pixels in the input image. The edge detector can be a Sobel operator that generates the magnitude values by taking the derivative of the input image values, i.e., the rate of change of intensity over a plurality of image pixels. A mask generator creates a mask based upon the values output by the edge detector. The mask can be used for masking input image values that are not in a region for which there is a sufficiently high edge magnitude. A mask applicator applies the pixel mask array to a selected image, e.g., the input image or an image generated therefrom (such as an edge direction image of the type resulting from application of a Sobel operator to the input image). A histogram generator generates a histogram of the pixel values in the masked image, i.e.

Abstract: Improved loudspeakers, systems and components are adapted to interconnect with many forms of communication media. In one embodiment, a speaker is mountable within a receptacle. The speaker includes a magnetic driver and a diaphragm mounted to a frame. The frame includes a mounting member extending from a surface of the frame behind the flange plane. The mounting member is engagable in a notch formed in the receptacle for securing the speaker within the receptacle. In another embodiment, a low-profile loudspeaker has a front-mounted magnetic driver disposed within a cone-shaped acoustic diaphragm. The magnetic driver includes a first rare earth magnet centrally disposed within an electromagnetic shielding material. In another embodiment, a low-profile, two-way loudspeaker includes a cone-shaped diaphragm and a dome-shaped (tweeter) diaphragm. A front-mounted magnetic driver comprises first and second rare earth magnets each centrally disposed within electromagnetic shielding material.

Abstract: A machine vision method for identifying a convex hull (i.e., a perimeter) around a set of points (e.g., such as may be found in an image of a ball grid array, or BGA, device) involves finding several "extreme" points on the convex hull. Points in the set that are outside a closed polygon defined by those extreme points are ordered to form a hull by, sorting them, identifying a line defined certain minimum and maximum coordinate values, and re-ordering the sorted points according to their position with respect to that line. The method further calls for testing successive points on the hull and removing those that do not define a convex hull using aspects of a Graham scan technique. The invention also provides a method for finding the angular orientation of a convex hull. The methods of the invention can be beneficially applied to the inspection of images of ball grid array devices, as well as other machine vision applications.

Abstract: A machine vision system for identifying the locations of bonding pads on an integrated circuit mounted in a lead frame. The system involves locating the bonding pads by searching an image with suitably rotated corner templates. A set of possible candidate bonding pads is created from the location of corner templates found during the search. The set is then scored utilizing matching criteria. The best candidate is selected from the set based upon the candidates' scores. The location of the bonding pad is then generated from the best candidate's corner template locations. The invention can be beneficially applied to locate bonding pads during wire bonding, as well as other machine vision applications.

Abstract: A machine vision system for identifying the locations of bonding pads on an integrated circuit mounted in a lead frame. The system involves rotating the image of the die to produce an image of the die unrotated with respect to the lead frame (the "counter-rotated image"). The counter-rotated image is searched with corner templates of the bonding pad. A set of possible candidate bonding pads is created from the location of corner templates found during the search. The set is then scored utilizing matching criteria. The best candidate is selected from the set based upon the candidates' scores. The location of the bonding pad is then generated from the best candidate's corner template locations. The invention can be beneficially applied to locate bonding pads during wire bonding, as well as other machine vision applications.

Abstract: The invention provides methods and apparatus for processing an image to identify the position of a linear pattern--for example, a line or a cross-hair comprising a plurality of intersecting lines. The system performs a first processing step for generating a projection of the image along axes aligned with an expected position of the linear patterns. A second processing step performs a mirror symmetry filtering on the projection to bring out a single peak corresponding to the center of the linear pattern. To further isolate that peak, the system performs a further filtering operation to remove peaks of lesser slope angle, so that only a highly sloped spike corresponding to the linear pattern will remain. The position of the center that peak corresponds to the center of the linear pattern in the original input signal.

Abstract: A coprocessor in an image processing system is coupled to the bus to which a CPU and RAM holding image data are also coupled. The coprocessor extracts an input pixel stream corresponding to input images from selected bus transactions, performs computations on the input stream to produce output pixel streams corresponding to output images, and inserts the output pixel streams into selected CPU-to-memory bus transactions so that the memory stores the data. The CPU generates the selected bus transactions with specially marked address and/or control signals. The coprocessor includes a lookup table, and a first row delay. The row delay accumulates the three most recent rows of input pixels, which are sent to Sobel and rank processing sections for neighborhood processing. The results are thresholded and formatted, and are either output directly or passed through an additional pair of row delays to accumulate three rows of result data for neighborhood peak detection.

Abstract: The invention comprises a method of completely sorting an unsorted data table in a single pass through the data. The method uses a relatively large amount of computer memory, but sorts the data at great speed. Specifically, each unsorted data word is scaled to a size equal to or less than the number of address locations in a sort table. The scaled value created for each unsorted data word is converted to an address increment which is added to the initial address of the sort table. The unsorted data word is then stored into the sort table at the above calculated address that is related to the value of the data word. In this way, most words are placed in a sorted arrangement without comparison or iteration. The invention also comprises a method for resolving conflicts where a calculated address for an unsorted data word already contains a sorted data word. In this case both words are then sorted with respect to each other to create a data subclass and stored in an auxiliary storage table.

Abstract: A marine seismic reflection prospecting system reduces coherent noise by applying a scale factor to the output of a pressure transducer and a particle velocity transducer positioned substantially adjacent one another in the water. The transducers can be positioned at a point in the water above the bottom and, thereby, eliminate downgoing components of reverberation, or they can be positioned on the water's bottom and, thereby, eliminate both upgoing and downgoing components of the reverberation. The scale factor, which derives from the acoustical impedance of the water or water-bottom material, can be determined both deterministically and statistically. The former involves measuring and comparing the responses of the pressure and velocity transducers to a pressure wave induced in the water.

Abstract: The invention provides an adaptive noise cancelling apparatus which operates to overcome a problem encountered in conventional noise cancelling circuitry when the signal-to-noise ratio at the sensor array is high--to wit, that the target signal is degraded, leading to poorer intelligibility. An apparatus constructed in accord with the invention selectively inhibits the adaptive filter from changing its filter values in these instances and, thereby, prevents it from generating a noise-approximating signal that will degrade the target component of the output signal.

Abstract: A marine seismic reflection prospecting system attenuates coherent noise through reinforcement of primary reflection data by the addition of corrected ghost reflection data. The system includes a seismic energy source, a detector, a wavefield separator, a time-shift element, and an element for generating an output signal representative of an additive linear combination of time-aligned primary and ghost signal components. The system's output is suitable for further pre-stack processing, e.g., NMO correction.