Abstract: Given a class hierarchy (a collection of classes and inheritance relations among them) and a program P that uses the hierarchy, a slice of the class hierarchy is computed with respect to the program by eliminating from the hierarchy those data members, member functions, classes, and inheritance relations that are unnecessary for ensuring that the semantics of P is maintained.

Abstract: This graphics system has a geometric sub-system that does not have to take into consideration memory resources for the raster sub-system of the graphics system. The graphics system sequentially receives from a host computer system data sets that define a graphic object and downloads texture data for graphics from the host computer system, so that geometric processing and rasterization are performed on the graphic object for display on a computer screen.

Abstract: A display device comprises a substrate, cathode means for emitting electrons, a permanent magnet and one or more supports between the substrate and the magnet. A two dimensional array of channels extends between opposite poles of the magnet, the magnet generating, in each channel, a magnetic field for forming electrons from the cathode means into an electron beam. A screen receives an electron beam from each channel, the screen having a phosphor coating facing the side of the magnet remote from the cathode, the phosphor coating comprising a plurality of pixels each corresponding to a different channel. Grid electrode means is disposed between the cathode means and the magnet for controlling flow of electrons from the cathode means into each channel, the grid electrode means having a plurality of apertures, each aperture corresponding to one of the channels.

Abstract: Computer systems generate and display objects represented by triangles defined by coordinates of vertices. The present invention generates potential coordinates of a simplified vertex based upon coordinates of a first vertex and a second vertex that define an edge of the triangles. A first set of triangles that are adjacent to the edge are identified, and a first set of error values corresponding to the vertices of the first set of triangles are derived. A second set of triangles tat share the simplified vertex are identified, and a second set of error values corresponding to the vertices of the second set of triangles are derived. The coordinates of the simplified vertex are stored in memory for reuse based upon a predetermined criterion involving the second error values and, preferably, one or more tolerance values. The second error values are derived from error values of a plurality of planar polygons corresponding to the first set of triangles.

Abstract: Effective use of optimizing techniques during compilation is difficult in programs that make liberal use of pointers or indirect function calls. The indirection often means that the compiler cannot precisely determine the set of objects pointed to by a pointer at a specific location in the program, and therefore cannot efficiently eliminate pointer redundancies in the code. The present invention provides an optimising method that reduces the size of alias sets associated with program pointers. During an initial compilation phase, intraprocedural information about pointer variables referenced in each function of the program is gathered and saved in a data structure called the pointer alias graph.

Abstract: A method of converting a plurality of strings stored in an input buffer to a plurality of evenly spaced strings in an output buffer involves first passing over the input buffer and, for each string, placing the string in the output buffer at a next available address. If the string length is longer than a maximum string length, the maximum string length is set to the string length and the string is set as the last incorrectly placed string in the output buffer. The next available address in the output buffer is incremented by the maximum string length plus the product of any positive difference between the current string length and previous maximum string length and the number of strings already placed in the output buffer. A second pass over said output buffer from the last incorrectly placed string in a direction opposite the first passing step moves each string within the output buffer to an address being a multiple of the maximum string length from the start of the output buffer.

Abstract: A quadrilateral or a hexahedron is used for a virtual object. If, for example, a quadrilateral mesh is composed of perfect squares and a voronoi diagram is dual to them, it is considered that the voronoi diagram comprises the perfect squares whose centers are connected to be a quadrilateral mesh. Accordingly, the quadrilateral mesh is generated by filling the object to be meshed with quadrilateral virtual objects corresponding to the voronoi diagram and connecting their centers.

Abstract: A method and appatatus for generating a quadrilateral mesh comprising a plurality of quadrilateral elements from a triangular mesh comprising a plurality of triangular elements by performing the following operations: for each candidate quadrilateral element comprising a pair of adjacent triangular elements (also referred to as a pair of adjacent triangular elements in embodiments), calculating a first evaluation value which represents a relationship between the candidate quadrilateral element and an alignment direction of quadrilateral elements specified by a user and a second evaluation value which relates to the shape of the candidate quadrilateral element; and selecting, by using the first and the second evaluation values, a candidate quadrilateral element to be used as an element of the quadrilateral mesh among the candidate quadrilateral elements.

Abstract: The method of the present invention discovers patterns in a sequence of characters in two phases. In a sampling phase, preferably proper templates corresponding to the sequence of characters are generated. Patterns are then generated corresponding to the templates and stored in memory. In a convolution phase, the patterns stored in memory are combined to identify a set of maximal patterns.

Abstract: An analogue display interface apparatus for providing analog color signals to a digital display unit includes a table look-up mechanism that provides digital representations of color signals to a color palette, wherein some of the values stored in the lookup table are received from the output of a calibration mechanism that displays a plurality of color choices on the digital display unit for selection by a user.

Abstract: The present invention groups character sequences by identifying a sequence of characters. A set of internal repeats in said sequence of characters is identified by a pattern discovery technique. For at least one internal repeat belonging to the set of internal repeats, it is determined if the internal repeat corresponds to a group of character sequences; If so, first data that identifies the sequence of characters and second data that associates the sequence of characters with the group of character sequences is stored in persistent memory. The pattern discovery mechanism discovers patterns in a sequence of characters in two phases. In a sampling phase, preferably proper templates corresponding to the sequence of characters are generated. Patterns are then generated corresponding to the templates and stored in memory. In a convolution phase, the patterns stored in memory are combined to identify a set of maximal patterns.

Abstract: Objects of a scene are grouped into sets. When rendering a plurality of pixels for display, for each pixel, a set identifier that corresponds to the visible object at the pixel is stored in an auxiliary buffer The information stored in the auxiliary buffer is utilized during picking in order to avoid the intensive task of traversing all of the objects of the scene to determine those objects intersected by the picking aperture.

Abstract: A computer graphics system stores graphics data the represents one or more three dimensional objects. The objects are represented by one or more primitives each defined by a plurality of vertices. The graphics systems renders the objects to generate a two dimensional image for display. During the rendering operation, coordinates of vertices of said primitives are subjected to a perspective transformation. The present invention provides a method and apparatus that uses at least one look-up table for mapping a texture function to pixels covered by at least one of said primitives.

Abstract: A magnet for use in a magnetic matrix display has a two dimensional array of apertures between opposite poles of the magnet. The direction of the magnetic field is such that the magnet generates, in each channel, a collimating magnet field for forming electrons from a cathode into an electron beam. A `keeper`, area around the periphery of the magnet is used to improve the linearity of the field strength in the apertures from apertures at the center of the magnet to apertures at the periphery of the magnet. The `keeper`, area may have control circuits placed on the surface of that area of the magnet. The keeper area may contain apertures which are not used for collimation and into which electrons are prevented from entering by a grid electrode or by a physical blocking means.

Abstract: A system and method for determining alias information at the inter-compilation unit level of a compilation process includes the steps of determining anti-alias sets from the alias information provided by the first stage of the compilation process, calculating pessimistic inter-compilation unit alias sets and refining these sets, after transitive closure as appropriate, with the anti-alias sets.

Abstract: The method and apparatus of the present invention provide for automatic recognition of fingerprint images. In an acquisition mode, subsets of the feature points for a given fingerprint image are generated in a deterministic fashion. One or more of the subsets of feature points for the given fingerprint image is selected. For each selected subset, a key is generated that characterizes the fingerprint in the vicinity of the selected subset. A multi-map entry corresponding to the selected subset of feature points is stored and labeled with the corresponding key. In the recognition mode, a query fingerprint image is supplied to the system. The processing of the acquisition mode is repeated in order to generate a plurality of keys associated with a plurality of subsets of feature points of the query fingerprint image. For each key generated in the recognition mode, all entries in the multi-map that are associated with this key are retrieved.

Abstract: A computer system generates a cylindrical environment map comprising a plurality of elements and associated information pertaining to images of a panoramic scene by storing in memory information associated with elements of a side image of the panoramic scene and information associated with elements of a top image and/or bottom image of the panoramic scene. For at least one element of the cylindrical environment map, if the element of the cylindrical environment map corresponds to an element of the side image, the information corresponding to the element of the side image is associated with the element of the cylindrical environment map. However, if the element of the cylindrical environment map corresponds to an element of the top image (or bottom image), the information corresponding to the element of the top image (or bottom image) is associated with the element of the cylindrical environment map.

Abstract: When data, such as tool data, is commonly accessible, there is a danger that concurrent user processes will make overlapping modifications and leave the data in an incomplete or incomprehensible state. The invention provides a locking mechanism to guard against this. The lock objects are maintained in pool or repository. Two types of lock objects are provided; shareable locks that may be shared by many user processes and permit only read access to the locked data, and exclusive locks, useable by only one user process at a time, that permit the owning process to modify the locked data.

Abstract: To correct the dependency of the transmissivity/applied voltage characteristics on color, a computing circuit is provided for generating corrected gray scale data by performing an addition or subtraction of the gray scale level related to at least one color. A delay circuit delays the gray scale data for uncorrected colors to maintain synchronization between the gray scale signals of all colors.

Abstract: The invention provides automatic acquisition and recognition of complex visual shapes within images. During an acquisition phase, models are derived from interest points acquired from a target shape. The models are stored in and can be retrieved from a lookup table via high dimension indices. When an image is inputted, triplets of interest points in the image are used to compute local shape descriptors, which descrb the geometry of local shapes in the image. In turn, triplets of local shape descriptors are used to compute high dimension indices. These indices arm used for accessing the lookup table having the models The models are used for the automatic recognition of target shapes.