Abstract: A method for distortion correction of computer-generated textured images maps vertices and texture coefficients from viewer space to projector space, so that environmental objects are pre-distorted upon the projection raster in order to appear in their proper form and perspective when the raster is projected onto a curved surface in viewer space, and viewed therefrom. Distortion correction is carried out by utilizing a piecewise-linear approximation for smoothly, continuously and closely approximating the required pre-curvature. The viewing space raster is subdivided into a number of triangles, within each of which a linear approximation is applied to the image mapping: the raster faces are first subdivided along the lines of a rectangular grid and the face fragments falling within each rectangle are then subdivided along the grid diagonal. This produces face fragments which are small enough so that a linear approximation provides an accurate transformation of each fragment.

Abstract: A memory arrangement for fast geometric transformation of an image is formed by a first memory for storing image values generated by an image-generating system, a second memory for storing image values corresponding to an image resulting from geometric transformation of image values from the first memory, and a third memory with the same number of memory addresses as the second memory and in which an assignment between the addresses of the first and second memories is stored.

Abstract: A digital image processor generates a digital signal responsive to an image signal representing a predetermined font demarcated by an outline, by which digital signal a digital image corresponding to the predetermined font is expressed on picture elements by using the luminance of each picture element, the digital image processor using a matrix having matrix elements corresponding to the picture elements, on which matrix the predetermined font can be expressed. The digital image processor digitalizes the image signal to determine the luminance of each picture element by using the matrix and an antialiasing process.

Abstract: A method and apparatus for evaluating and rendering parametric curves such as non-uniform rational b-spline (NURBS) curves. NURBS data consisting of control point data, knot values and other data defining a curve is stored in system memory as a sequence of records such that successive spans of the curve are defined by successive individual data records in conjunction with a predetermined number of immediately preceding data records of the sequence. A graphics control processor transforms the control point data from modelling coordinates to view coordinates, converts the transformed control point data to homogeneous coordinates, and generates parameter points along the curve. Parallel floating point processors simultaneously evaluate the homogeneous coordinates of the curve at each parameter point along the curve using the Cox-de Boor procedure. A further floating point processor converts the homogeneous coordinates to geometric coordinates for subsequent rendering and display of the curve.

Abstract: A method quickly identifies an irregular graphic shape displayed on a video terminal. In an "off-line" operation, the method associates transparent regular graphic shapes, such as boxes, with the irregular graphic shapes. The regular graphic shapes do not overlap one another and are shaped, sized, and located so that one or more of the regular graphic shapes together approximate each irregular graphic shape. The regular graphic shapes are defined in a data table which includes a single data node for each of the regular graphic shapes. During the execution of an application computer program, the irregular graphic shapes are displayed at the video terminal, but the regular graphic shapes are not displayed. In addition, the application computer program manages a video pointer in real time so that a user may move the video pointer to any location on the display of the video terminal. The program investigates the table of regular graphic shapes to select a node corresponding to a regular graphic shape.

Abstract: A method for automatically linking program execution status information during the execution of a program to display the execution status information of the program by a multi-window display having a plurality of sectioned areas for use in the development of the software program.

Abstract: A method for determining the boundaries between regions of color making up polychromatic document pages or images, in order to compensate for misregistration of printing plates in printing, and thereby to prevent light leaks and other errors at the boundaries so determined. A map of the boundaries is generated, to which trapping operations are applied to form a structured graphic object that is included as the last object imaged in the data representing the original image. The geometrical description of the boundary map determined according to the method of the invention is independent of specific trapping decisions applicable to the associated image.

Abstract: A character pattern forming apparatus has a ROM, a RAM, and a CPU. The ROM includes a first memory area for storing a plurality of segment data respectively designating different segments of a character each segment having one or more dots arranged in a row and column of a pattern. The first memory also stores predetermined arrangement forms for forming line patterns. A second memory area of the ROM stores a plurality of character fonts each having a plurality of line pattern data which respectively specify a type segment forming a basis for each line pattern, and a dimension and an arrangement of said line patterns. The RAM includes a third memory area in which line patterns for at least one character are stored. The CPU reads from the second memory area a character font of a character to be formed, reads from the first memory area segment data specified by each of the line pattern data for the character font.

Abstract: An iconic programming system wherein each icon within the system may have zero or more data input connections, zero or more data output connections, an optical sequence input connection, and an optional sequence output connection. Each of these connections may be used to graphically connect each icon to another icon to form a network of icons that operates as a computer program. Execution of the network is accomplished by processing each icon and performing any programming functions represented by the icon. After an icon is processed, data resulting from the processing is sent to all icons connected to data or sequence output connections, and those icons are scheduled for processing. Any start icons in the network are scheduled to process first. If an icon is scheduled for processing and it does not have data available to an input, the icon connected to that input is scheduled.

Abstract: A filing system scans original documents and converts the information on the documents into picture information which is then condensed and stored in a file storage block. If an index for the files is specified, an index of the picture information is stored in a file image memory having a plurality of fixed memory areas. Coordinates of an area of the original document enclosing the picture information on the original document can be specified, and tables in memory indicate the correspondence between specified areas, the corresponding fixed memory areas in the file image memory, and the addresses of the corresponding stored files. To retrieve the files, an operator can either press certain areas on a document with a stylus pen, provide an identifier of the files, or place marks on an index document prepared by the filing system.

Abstract: A iconic programming system process represented by a directed graph of icons and connections. When a user starts execution of the iconic system, the system first separates the icons into a list of threads starting with icons at the highest level of the graph. Icons at lower levels of the graph, such as icons within subprograms or virtual threads, will be placed on a thread when the subprogram or virtual thread is started. Virtual threads contain all icons connected to the output of an iteration icon. Each thread is processed by selecting a start icon, or by randomly selecting an unconstrained icon if no start icons are present. Processing continues by processing each icon which has all data input available. Each of the threads is processed by processing one icon per thread in each cycle, until all icons have been processed.

Abstract: A method for drawing a composite figure by combining a plurality of figures. The contours of the plurality of figures are first drawn, and thereafter the insides of the contours are successively filled with in accordance with plane filling attributes of the corresponding figures. Thus, a composite figure with unnecessary contours made to disappear at superposed portions of the figures can be obtained.

Abstract: An apparatus having a dot data preparing device for converting original outline data representative of an outline of a character into dot data indicative of image dots to be formed at picture elements which lie within the character outline, when the character outline is superimposed on a coordinated pixel screen wherein the picture elements are defined by parallel x-axis pixel lines and parallel y-axis pixel lines perpendicular to the x-axis pixel lines. The apparatus includes a device for calculating a coordinate value of a maximal or minimal point of a segment of the character outline in an x-axis or y-axis direction, and an outline moving device for moving the outline such that the coordinate value of the maximal or minimal point has a predetermined positional relationship with the pixel lines. The dot data preparing device prepares the dot data, according to the outline data representative of the outline moved by the outline moving device.

Abstract: A method and apparatus for simultaneously rendering multiple scanlines. Using a scanline approach to rendering, multiple scanlines may be rendered simultaneously through the use of parallel rendering means. The rendering of multiple scanlines in parallel is enabled by creating scanline independence. Scanline independence is achieved by interpolation through direct evaluation of object information. During the rendering process each of the rendering means vertically interpolates to identify a span corresponding to the scanline being rendered. A span is identified by it's X, Y coordinates on a scanline. The scanline being rendered provides the Y-coordinate.

Abstract: A system and method for interfacing a video subsystem capable of driving a video display monitor to a personal computer (PC) architecture. The system and method involves connecting the video subsystem to a host bus via a host bus video interface. The host bus communicates directly to a central processing unit (CPU) and to a slower system bus through buffers. The central processing unit as well as a system bus master connected to the system bus can communicate at high speeds to the video subsystem. The host bus video interface includes a fast temporary storage buffer so that the CPU or the system bus master, during a write cycle to the video subsystem, can write data at high speed to the video subsystem. The video subsystem may further include SRAM in its video memory to increase performance.

Abstract: A character generator and method which requires reduced storage memory space for a character memory by virtue of generating bit fill patterns that fill character borders. The borders are, in turn, generated from partial borders that are local to the starting, ending, and any middle coordinate points of an imaginary baseline roughly drawn along the centerlines of strokes making up the character. As especially applied to Japanese and Chinese character sets, the character generator and method further improve on memory storage savings by separating basic characters from compound characters. The compound characters are then generated in terms of reshaped and repositioned basic characters, thus eliminating the redundancies that would otherwise exist.

Abstract: A method for constructing object-local sampling histories for efficient path tracing. The present invention provides a technique for efficiently producing computer generated two-dimensional synthetic images of three-dimensional scenes. Objects within in the scene (10) are assigned packs (30,36) containing one or more elements (32,38). For light reflective objects (19,O1), each element (32) of the object's pack (30) represents a region of the object's reflection hemisphere (30) through which incident light is equally likely to be reflected. For light transmissive objects (19,O1), the elements (32) represent analogous regions of equal transmission. For light emitting objects (L1), each element (38) of the object's pack (36) represents a region of equal light emission probability.

Abstract: Apparatus and method for rendering graphic images as bit maps, including: (1) an input for receiving digital input commands; (2) a command interpreter to interpret the input commands and convert them into commands suitable for use inside the system; (3) a halftone screening section; and (4) a rendering section which outputs data suitable for use by a raster display or marking engine. The method and apparatus render multiple output pixels during each clock cycle and apply halftone screens or gray fills to an image.

Abstract: An image interpolation apparatus receives an image signal in the frequency domain. The image signal is supplied to a filter circuit. The output of the filter circuit is transformed by a two-dimensional fourier transformation circuit into a filtered image signal in the spatial domain. The filtered image signal is linearly interpolated by an interpolation circuit to enlarge or reduce the image representing the image signal. The filter circuit, the fourier transformation circuit and the interpolation circuit are under the control of a processor. The processor sets the filter circuit a filter function representing the inverse of the modulated transfer function of the interpolation circuit to compensate for the degradation caused by the modulated transfer function of the interpolation circuit.

Abstract: In an initial set up sequence, N pels of an original image are stored in N memory positions of an input buffer. The N pels are converted to M pels, which are stored in M memory positions of an output buffer, where M and N are integers larger than 0. In the case of N<M, an enlargement of the original image is made, and in the case of N>M, a reduction of the original image is made. An address counter pointing to an address of a memory position of the input buffer is initially reset to 0. An address counter pointing to an address of the memory position of the output buffer is also reset to 0. The values -N, M, and an initial sum value S (where S is integer satisfying -N.ltoreq.S<M) are initially stored in three registers, respectively. The initially stored sum value S is repeatedly updated to control the scaling up operations or the scaling down operations. There is a first device which determines or checks whether the sum value is negative, or not.