Raster Graphics Research Articles

A stack-based approach for shading of regions

The method for shading of regions is considered as the basic study in raster graphics. A stack-based approach is presented in the paper. Without sorting of the boundary coordinates, the time and space consumed by the shading procedure are considerably saved. The facilities of the approach in 3D graphics are also illustrated.

Elemental Counterpoint with Digital Imagery

In musical counterpoint, separate melodic lines move simultaneously while making structural sense with their temporal neighbors and the overall musical form. The levels of control of abstract visual material now available through computer-generated raster graphics make it possible to establish a similar contrapuntal rigor with visual elements and to explore a structured method of temporal visual design. Building on earlier work in time-based color and some fundamental observations of visual balance, the author proposes and illustrates a formal approach to abstract animation that parallels contrapuntal music technique.

Characterization of the chemical homogeneity of solid-state materials by chemometric methods. Multivariate aspects and general recommendations

Data from milliprobe analysis of a copper standard material by spark source mass spectrometry have been investigated using multivariate methods in addition to earlier — predominantly univariate — treatment in order to derive some general recommendations for characterizing the chemical homogeneity of solids. A “disarmed” MANOVA test with the locations as effect variables and the normalized concentration data of the diverse chemical elements as replicates provided a highly rigorous Yes-No decision on homogeneity from an overall point of view. For more detailed information, data visualization by raster graphics combined with cluster analysis, principal components analysis, and non-linear mapping proved a useful explorative tool, particularly in the (here assumed) case without any preinformation. Dependent on how these methods are used, information on locations of inhomogeneities or on correlations between the analytes results. It has been shown that seeking for correlations should be the first explorative step. Employing the further steps to correlating elements increases the rigour of detecting element-specific inhomogeneities. On the other hand, including all the determined elements enables a more critical judgment of “collective homogeneity”. To confirm multivariate results on inhomogeneity by statistical means, the revealed groups of sub-samples should be tested by linear discriminant analysis. Deviations from a homogeneous distribution can be detected and/or characterized for any single element (or correlating elements) individually by univariate methods based on models of the spatial distributions, if these can be presumed a-priori or after preliminary investigations.

Object-oriented versus bit-mapped graphics interfaces: performance and preference differences for typical applications

Abstract This study used a standardized evaluation to compare two direct manipulation graphics interfaces. The interfaces investigated were: (I) object-oriented (vector) graphics; and (2) bit-mapped graphics (object-oriented graphics interfaces are not to be confused with object-oriented programming or object-oriented data bases). Experienced and novice subjects performed objectively derived benchmark tasks appropriate for two-dimensional graphics packages. Both performance and preference data were collected. Task completion time, aborted attempts, learning effects, and errors consituted the performance measures. For the preference data, subjects completed questionnaires to rate the interfaces on both an absolute and a relative basis. Results indicate that the object-oriented graphics interface is superior to the bit-mapped interface for most tasks included in the benchmark set. The advantages of the object-oriented interface are especially pronounced for graphic manipulations such as rotation, resizing (...

Fun and games and microcomputer interfacing (laboratory exercises)

A microcomputer laboratory is described in which students learn computing concepts by carrying out exercises that allow them to experience in an immediate and tangible manner the fruits (and sometimes follies) of their programming efforts. The exercises include a transparent serial communications link (different from the onboard link on the 68 KECB single-board computer); generation of computer music; decoding patterns from a bar wand; low-resolution, bit-mapped graphics; control of a turtle robot; low-level control of floppy-disk drive (and the subsequent writing of disk-handler software); movement of an x-y drill positioner; data logging (including statistical analysis of the readings taken); control of a slot-car set; and model railway scheduling. Several of these exercises are described.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Recursive bisection line algorithm

This article presents a new algorithm for drawing lines on raster graphics devices. The algorithm is not related to Euclid's algorithm but instead is based on a fractal definition for the line. The fractal has the same dimension as the topological dimension of the line. The recursive nature of the algorithm results in fewer decisions being made in comparison with other algorithms. Therefore, this line algorithm performs faster especially with lines near to horizontal, diagonal, or vertical. The algorithm does not produce a palindrome and on low resolution devices may not appear to be perfectly straight. It is shown, however, that the line accuracy improves in proportion to the display resolution.

Logical and layout structures of documents

Document preparation systems are commonly layout oriented in that way that the user interactively creates and modifies frames for text, mathematical formulas, raster or geometric graphics, etc. For batch-oriented systems the user manipulates the process of formatting by inserting control commands into the plain text. These modify the position or graphic aspect of the following text portion. Many systems provide a macro mechanism to combine lengthy and repeatedly used control commands to macros, with the result that the text is interpersed with macrocalls. Macro calls. Macro calls are often logical delimiters. They subdivide the plain text into a linear of document objects, which forms the linear description of the logical document structure similar to a tree. It must be mentioned that in most systems there is no direct support or representation of the logical document structure. The logical structure exists only in the author's mind and the author himself compiles the logical document objects and their hierarchical relationship to physical layout representation. More flexiblw and interactively formatting editors for structured document preparation presuppose a strong distinction of logical and layout structure and incorporate a formal description of the mapping, how the layout is derived from the logical structure. The logical structure is an enriched tree-oriented representation, in which between pbjects are constrained by grammatical specification. The layout structures define the layout relationships on the physical pages of the document and they are also constrained by grammatical spedifications. Another goal is to define the mapping well known as formatting by high-level specification for classes of documents, in order to be able to generate automatically formatting editors by high-level specifications.

Computer graphics of hydroxyapatite and β-tricalcium phosphate

Hydroxyapatite (HA) and β-tricalcium phosphate (TCP) were studied by computer graphics with a personal computer. Crystal models of fluoridated hydroxyapatite and fluorapatite, in which F− ions are substituted into some or all OH− positions, were also drawn. Data on the structural coordinates of the hydroxyapatite and β-TCP crystals were put into a protein graphics program in Angstrom units. The connection of each element, with front and rear, was displayed by the shade-line erasing method, and the solidity of the image was expressed by the degree of lightness from the light source. The colour tint was obtained by the Raster graphics method. A fine picture can be obtained with the photo program. Rotating the graphics freely around the X, Y, and Z axes gives a view from any direction. The computer graphics demonstrated visually that F~ ions contribute to stabilize the hydroxyapatite crystal and that β-TCP has an unstable structure due to 0.5 probability of Ca2+ ions and [P04-Ca-Ca-Ca-PO4] zigzag chain.

Real-time robot motion planning using rasterizing computer graphics hardware

We present a real-time robot motion planner that is fast and complete to a resolution. The technique is guaranteed to find a path if one exists at the resolution, and all paths returned are safe. The planner can handle any polyhedral geometry of robot and obstacles, including disjoint and highly concave unions of polyhedra.The planner uses standard graphics hardware to rasterize configuration space obstacles into a series of bitmap slices, and then uses dynamic programming to create a navigation function (a discrete vector-valued function) and to calculate paths in this rasterized space. The motion paths which the planner produces are minimal with respect to an L 1 (Manhattan) distance metric that includes rotation as well as translation.Several examples are shown illustrating the competence of the planner at generating planar rotational and translational plans for complex two and three dimensional robots. Dynamic motion sequences, including complicated and non-obvious backtracking solutions, can be executed in real time.

A Computer Graphic Method to Enhance the Display and Interpretation of Three-Dimensional Data

Three-dimensional density information derived from electron micrographs may reveal complex structural features which are difficult to interpret from one or more two-dimensional views. Displaying a series of static views on a graphics device in quick succession provides an effective means to examine the structure dynamically and in a way which enhances the depth perception.Digital images derived from three-dimensional models are transfered to the memory of a 1280x1024 resolution (8-bit pixel) color raster graphics device (Lexidata 3400, Adage Inc., Billerica, MA) and displayed on a 19 in. color monitor at a 25-30 Hz interlaced refresh rate. Individual pixels are displayed as one of 256 different colors or grey levels from a palette of up to 224—1 combinations. An entire series of images is loaded into the graphics memory in a sequential order, usually in rows. The displayed series is zoomed up to focus on a single frame and separate frames are displayed in appropriate sequence by panning to different regions of the graphics memory. The frequency at which each frame can be displayed is adjustable and only limited by the refresh rate of the monitor. Such dynamic image sequences can be photographed with a standard video camera and replayed on a television monitor with a video cassette recorder. The programs for displaying image data are written in FORTRAN and have been implemented on a VAX/VMS 8550 minicomputer (Digital Equipment Corp., Maynard, MA).

4882683 Cellular addressing permutation bit map raster graphics architecture

4882683 Cellular addressing permutation bit map raster graphics architecture

Differences in Performance and Preference for Object-Oriented vs. Bit-Mapped Graphics Interfaces

This study used a standardized evaluation to compare two direct manipulation graphics interfaces: (1) object-oriented (vector) graphics and (2) bit-mapped graphics (object-oriented graphics interfaces are not to be confused with object-oriented programming or object-oriented data bases). Experienced and novice subjects performed objectively derived benchmark tasks appropriate for two-dimensional graphics packages. Both performance and preference data were collected. Task completion time, aborted attempts, learning effects, and errors constituted the performance measures. For the preference data, subjects completed questionnaires to rate the interfaces on both an absolute and a relative basis. Results indicate the superiority of the object-oriented graphics interface to the bit-mapped interface for most tasks, especially manipulation (e.g., scaling, moving, etc.) of graphics. The implications of these results for the use of direct manipulation graphics interfaces are discussed.

Document Architecture Standards Evolution

The Office Document Architecture (ODA) is a set of standards for structuring and encoding documents so that they can be interchanged between dissimilar systems, viewed as intended by the document originator, and processed by other users. <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> ODA is a joint effort of the International Organization for Standardization (ISO) and the International Telegraph and Telephone Consultative Committee (CCITT). The standards describe documents in terms of their structure and content. Structures are hierarchical and sequential. Content is separated and processed separately from document structures. Three types of content are permitted: text, raster graphics, and geometric graphics. Rules for maintaining relationships between document elements are also defined. There are plans to extend the ODA document processing model and to develop standards for new content types such as voice and spreadsheets.

A characterization of ten rasterization techniques

With widespread use of raster scan displays and the ever-increasing desire for faster interactivity, higher image complexity, and higher resolution in displayed images, several techniques have been proposed for rasterizing primitive graphical objects. This paper characterizes the performance of these techniques and shows how they evolve for more complex images on higher resolution displays. This characterization will not only show the strengths and deficiencies of existing rasterization techniques, but will also reveal new architectures for future raster graphics systems.

ODA: a document architecture for open systems

The main concepts and aims of the new ISO 8613 standard — generally referred to as Office Document Architecture — that has been jointly published by the International Organization for Standardization and the Consultative Committee on International Telephone and Telegraph, is described here. ODA provides a general information architecture which can be used as a basis for encoding documents so that they can be transferred between dissimilar document processing systems. The architecture supports the representation of multi-media documents (containing text, raster graphics and computer graphics) in both revisable and final forms. ODA is expected to have a significant role in the integration of office systems, particularly those that operate in an Open Systems Interconnection environment.

AESOP: a simulation-based knowledge system for CMOS process diagnosis

The AESOP system is a prototype computer tool designed to provide the automatic analysis and diagnosis of process deviations through electrical measurements on specific test structures. Causal relations necessary for diagnosis were determined through extensive use of numerical simulation for the CMOS process investigated with this prototype. The use of physics-based numerical simulators complements the previous approach of experimental knowledge engineering to determine these relations. Interaction with the user is facilitated in the AESOP system through the use of customized window-based editors and bit-mapped graphics. The abilities and limitations of the AESOP prototype are demonstrated on several sets of end-of-line test data.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Computer graphics of apatite crystals

Hydroxyapatite was studied by computer graphics. The data of structural coordinates of hydroxyapatite crystal was put into a protein graphics program in A units. The connection of each element, with what comes front and rear, was displayed by the shade-line erasing method, and the solid-image was expressed by the degree of lightness from the light source. The tint of color was drawn by Raster graphics method. A fine picture can be obtained with the program. Rotating the graphics freely in an angle around X, Y or Z axis, gives a view from any direction. Crystal graphics model of fluoridated hydroxyapatite, in which F- ions substituted in part into OH- position, was also drawn.

Identification of frequency domain models for nonlinear systems

This paper presents a computer-aided engineering approach for identification of linear models from a set of frequency response data. The approach is based on a new system identification technique. The primary intention of the developed system identification technique and the associated software is to identify linear models for nonlinear systems whose input/output behaviour is characterized by their corresponding sinusoidal-input describing function models. However, the technique may also be applied to identification of linear models from experimental frequency response data. At present, the identification approach and the associated software is limited to single-output, linear, deterministic, and time-invariant systems. A computer-aided engineering environment based on the developed system identification technique has also been developed. The software is developed on a Harris-800 super-minicomputer and a Tektronix 4115B high resolution, raster, and color graphics terminal.

A forest shading model using bit-mapped graphics

A digital model has been developed for evaluation of the percentage fraction of the ground surface that is shaded by trees or other terrain elements. The model uses the bit-mapped graphics on a Hewlett-Packard 9816 computer to estimate the relative portion of the ground that is shaded at different solar elevations and azimuths. Different tree types and spacings can be built easily into the model, which also may be employed to evaluate the shade cast by high-rise and other building structures.

'PostScript' prints anything: a case history

The development history of the page description language PostScript is presented. Several key problems in the development are described: laser printer, a harbor simulation that drove the language-to-be toward its object orientation, font algorithm creation, and image reduction and analysis. Key technical developments that aided the establishment of PostScript are also mentioned; these include the Apple Macintosh microcomputer and its need for bit-mapped graphics printing, cheap laser printers, and cost declines in memory.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>