“One-point touch input of vector information for computer displays” by Herot and Weinzapfel

  • ©Christopher F. Herot and Guy Weinzapfel




    One-point touch input of vector information for computer displays



    The finger as a graphical stylus enjoys a coefficient of friction with glass sufficient to provide input of direction and torque as well as position from a single point. This report describes a pressure-sensitive digitizer (PSD) capable of accepting these force inputs, and discusses a set of five simple input applications used to assess the capabilities of this device. These applications include techniques for specifying vectors, and pushing, pulling, dispersing and reorienting objects with a single touch. Experience gained from these applications demonstrates that touch and pressure sensing open a rich channel for immediate and multi-dimensional interaction.


    1. Nicholas Negroponte. On being creative with computer aided design. In Information Processing 77, B. Gilchrist, Editor, IFIP, North-Holland Publishing Co., New York, 1977.
    2. Dr. Richard A. Bolt. Spatial data – management – interim report. Architecture Machine Group, M. I. T. Cambridge, Massachusetts, November, 1977.
    3. William Donelson. Spatial management of information. SIGGRAPH ’78, Proceedings of the Fifth Annual Conference on Computer Graphics and Interactive Techniques. Atlanta, 1978.
    4. Guy Weinzapfel. Mapping by yourself. Proceedings of the conference Interactive Techniques in Computer Aided Design, Bologna, Italy, 1978.
    5. A discussion of various TSD technologies is provided by Dr. Richard A. Bolt. Touch sensitive displays. Architecture Machine Group, M.I.T. Cambridge, Massachusetts, September, 1976.
    6. TSD work is continuing under the aegis of ONR Contract Number N00014-75-C-0460 with Elographics Corporation furnishing a transparent sensing medium laminated to a Tektronix 650 display.
    7. Several “kinesthetic” systems, that is systems incorporating force feedback, are summarized by Frederick P. Brooks, Jr. The computer “scientist” as toolsmith – studies in interactive graphics. In Information Processing 77, B. Gilchrist, Editor, IFIP, North-Holland Publishing Co., New York, 1977. However, none of the systems summarized in this paper correlates physical and graphical feedback at a common locus.
    8. P.J. Kilpatrick. The use of a kinesthetic supplement in an interactive graphics system. Ph.D. dissertation, University of North Carolina, Chapel Hill, N.C., 1976.
    9. A.M. Noll. Man-machine tactile communication. Ph.D. dissertation, Polytechnic Institute of Brooklyn, Brooklyn, N.Y., 1971.
    10. The display used for this project is an IMLAC PDS-1 dynamic CRT. This display may be driven by any of the laboratory’s several Interdata minicomputers (models 70, 85 or 7/32). The operating system (MAGIC) and the display software are both of Architecture Machine Group design.
    11. A more complete technical description of the TSD is provided in the reference cited in (5) above.
    12. A general discussion of task performance related to diminished and augmented feedback is provided in Paul M. Fitts and Michael I. Posner. Human Performance. Brooks/Cole Publishing Co., Belmont, California, 1967.
    13. Subsequent to this study, it was learned that Robert Anderson and Ivan Sutherland, working at Rand Corporation had explored a pressure-sensing device to locate the x,y position of a touch. Though the Rand device used a considerably different mounting configuration, the calculated touch point migrated as the touch pressure was varied. To minimize this problem, positions were calculated using a low pressure threshold.

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