Abstract: Information of a character string or the like described on a page of a book is obtained from three-dimensional data of the book. A book electronization device (1) includes a surface specification unit (12) that specifies a page region corresponding to a page of a book in three-dimensional data of the book, which has data values corresponding to a sheet of the book and a gap between sheets, and a data generation unit (13) that maps a character string or graphic in the page region to a two-dimensional plane and generates two-dimensional page data including a character string or graphic written or drawn in the book.

Abstract: Information of a character string or the like described on a page of a book is obtained from three-dimensional data of the book. A book electronization device (1) includes a surface specification unit (12) that specifies a page region corresponding to a page of a book in three-dimensional data of the book, which has data values corresponding to a sheet of the book and a gap between sheets, and a data generation unit (13) that maps a character string or graphic in the page region to a two-dimensional plane and generates two-dimensional page data including a character string or graphic written or drawn in the book.

Abstract: According to the present invention, a method is provided for assigning or converting volume data values defined at the center of cells to volume data values at node points, considering the residuals.

Abstract: A rendering method is provided that can materialize rendering processing from volume data at high speed using a surface rendering processor without restrictions on the structure of volume data to be processed. In the method, the sampling points of volume data V over a 3-D region are, in principle, arranged on the surfaces Q.sub.1, Q.sub.2, . . . Q.sub.n in equal intervals along a viewing ray L around viewing point p, and these surfaces are extracted as a set of triangles T.sub.i. Then, the volume data at each vertex of these triangles and the gradient vectors of this data are obtained by interpolation and generated as a triangle data group. High-speed volume rendering is materialized by displaying the data groups of these partially transparent triangles using a surface rendering processor. Since existing programs can be used for generation and processing of triangle data groups, there are no restrictions on the structure of the volume data to be handled.

Abstract: A method and apparatus for displaying stream lines in a space are disclosed. First, the space is divided into a plurality of tetrahedral cells. Position data of each vertex of the tetrahedral cells and vector data at each position are collected. A critical point for each tetrahedral cell is then computed. The critical point is within the tetrahedral cell and for which the vector data becomes zero. Using the collected position and vector data, a Jacobian matrix J is calculated when such a critical point is found, and eigenvalues of the Jacobian matrix J are also calculated. Next, the starting point of a stream line within a tetrahedral cell is calculated for each of the eigenvalues by moving a microscopic distance from the critical point. Finally, a stream line is calculated from the starting point, and the stream line is displayed.

Abstract: To provide high-speed volume rendering without computing the points at which a viewing ray intersects with the boundaries of a volume data area.

Abstract: An isosurface is composed of grid points having a predetermined scalar value. The method and apparatus of the present invention generates an isosurface by extracting from volume data a first grid point having a minimum scalar value and a second grid point having a maximum scalar value. A list of polyhedrons that intersect a line connecting the first grid point to the second grid point is generated and stored. The isosurface is generated in accordance with the list of polyhedrons and the predetermined scalar value. Because the volume data obtained by scientific and technological calculation or the like is kept in the form of a polyhedron list having an associated maximum scalar value and minimum scalar value, generating an isosurface according to a predetermined scalar value can be accomplished at high speed.

Abstract: Methods and apparatus are provided for generating isosurfaces, given input data that includes (1) the representation of a set of points in three-dimensional space; (2) connectivity information with respect to the set of points and (3) a scalar field. The methods and apparatus allow the desired isosurfaces to be produced efficiently on all hardware platforms, including those not equipped to rapidly generate such isosurfaces using normally computation intensive processes, by utilizing a precomputed isofacet configuration table and predefined tetrahedron component labeling data (preset relationships among the vertices, edges and faces of a tetrahedron). Further aspects of the methods and apparatus include (1) methods and apparatus which support the selective display of isosurface and contour line images, and (2) methods and apparatus which utilize parallel processing techniques to enhance the efficiency of the isosurface generation process.

Abstract: Portions showing greater specular reflection of an object to be displayed are displayed with pixels whose opacity, .alpha..sub.1, is emphasized according to the specular reflected component of a shading model, in which case the specular reflected component thus calculated for shading is also utilized for arithmetic operation of emphasized opacity, .alpha..sub.1, and high-speed processing is sought through tabulating various variables such as .alpha..sub.s (an additional opacity introduced for emphasis by a specular reflected component), .alpha..sub.n (a primary opacity), and G (a gradient vector).

Abstract: A method and apparatus for generating image data representing an iso-valued surface. A series of points in three dimensional space each having positional data and an assigned scalar value is analyzed by dividing the space into tetrahedral elements, generating tetrahedral element representative normal vectors, generating vertex representative normal vectors data, and calculating pixel values for viewing rays passing through the tetrahedra. Tetrahedral elements have the advantage of requiring only the solution of linear equations instead of quadratic equations. The use of representative normal vector data rather than geometric data for each associated triangle greatly reduces the storage requirements for processing the data. The reduced data storage and associated reduced processing time allows generation of iso-valued surfaces at high speed with a minimum memory requirement.