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Raster scan computer graphics displays with "real time" character generators have previously been limited to alphanumeric characters. A display is described which extends the capabilities of this organization to include general graphics. The feasibility of such a display is shown by deriving the minimum number of patterns required in the read only memory of the character generator to synthesize an arbitrary line. The synthesis process does not compromise picture quality, since the resulting dot patterns are identical with those of a conventional raster display. Furthermore, the time constraints of a raster display are shown to be satisfied for a typical design for very complex line drawings. [ABSTRACT FROM AUTHOR]

A television-like scanned-display system has been successfully Implemented on a Honeywell DDP424 computer installation. The scanned image is stored in the core memory of the computer, and software scan conversion is used to convert the rectangular coordinates of a point to the appropriate word and bit In an output display array in core storage. Results thus far Indicate that flicker-free displays of large amounts of data are possible with reasonably fast graphical interaction. A scanned Image of size 240 X 254 points is displayed at a 30 frame-per-second rate. [ABSTRACT FROM AUTHOR]

Raster scan computer graphics with"real time" character generators have previously been limited to alphanumeric characters. A display has been described which extends the capabilities of this organization to include general graphics. Two fundamentally different scan conversion algorithms which have been developed to support this display are presented. One is most suitable to non- interactive applications and the other to Interactive applications. The algorithms were implemented in Fortran on the CDC6400 computer. Results obtained from the implementations show that the non interactive algorithms can significantly reduce display file storage requirements at little cost in execution time over that of a conventional raster display. The interactive algorithm can improve response time and reduce storage requirements. [ABSTRACT FROM AUTHOR]

The article focuses on the spring Joint Computer Conference that would be organized by Association for Computing Machinery on May 14-16 in Boston, Massachusetts. In this tempestuous age of societal upheaval, reawakening responsibility, and involvement, people everywhere are demanding solutions to, or relief from, the problems which beset the society. Another area the technical program emphasizes is computer graphics. Believed to be of greatest potential as the mechanism for man-machine communication, techniques and applications of computer graphics will be described. It will be pointed out that present hardware and software techniques for its use are being developed in an uncoordinated manner. The result is that communication about the level of achievement and development in computer graphics, particularly software, is poor. Increasingly, the forces, actions, and reactions propagated throughout the land by information processing technology are accelerating in social impact-- for better and for worse. At a panel entitled "URGENT--Increased Dialogue with Society" participants will establish the bases for the need for such discussions and will recommend specific actions to implement the expanded discourse.

The article focuses on the complicated "hidden line problem" in computer graphics which has been solved by Phillipe Loutrel, a graduate student in electrical engineering at the New York University School of Engineering and Science. The problem involved programming a computer to generate perspective drawings of three-dimensional objects and then identify and, if desired, eliminate any edges not visible from a specified vantage point. The solution involves a procedure that enables a computer, in seconds, to generate line drawings of any polyhedron with the "hidden lines" either deleted or shown by dashes. Loutrel cut the calculation time from minutes to seconds by devising techniques that classify and immediately eliminate most of the totally invisible edges and then minimize the testing necessary to identify the remaining hidden edges. Loutrel also extended his technique to handle complex illumination problems. The technique enables computers to calculate what lighted faces of the object would be visible to the observer.