“Acoustic radar graphic input device” by de Bruyne

  • ©P. de Bruyne




    Acoustic radar graphic input device



    Accurate X,Y position determining digitizers presently require a precision array of wires embedded in the tablet. In rear-projection tablets these wires tend to limit the optical quality of images projected on the screen. Principles of acoustic radar are applied in a device which achieves better resolution, at a lower cost and without the use of wires, either in a tablet or a cursor. The function of acoustic reflectors for automatic calibration is described, achieving an accuracy of + mn; 0.01% of the distance to the sensors. In the case of small tablets, a hand-held stylus may be tracked at the rate of 900 locations a second.


    1. Brenner, A.E., de Bruyne, P. SONIC PEN: A digital stylus system. IEEE Transactions on Computers, V. C 19, No 6 (1970) pp. 546-548. |he device is made by Science Accessories Corp. of Southport, Conn.
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    3. Mason, W.P. Physical Acoustics V. 1 Part A (1964) pp. 169-270, Academic Press N.Y.
    4. Sell, H. Eine neue Kapazitive Methode zur Umwandlung mechanischer Schwingungen in elektrische und umgekehrt. Z. f. technische Physik (1937) 3.
    5. Anke, D. Luftschallwandler nach dem Sell-Prinzip für Frequenzen von 50 kHz bis 100 kHz. Acustica V. 30 (1974) pp. 30 – 39.
    6. Skolnik, M. I. Radar Systems, McGrawhill Book Co. N.Y. (1962) p. 43.
    7. de Bruyne, P. Authentication of Handwriting with SONAR. Proceedings of the 1980 International conference “Security through Science and Engineering” Berlin ( to be published Sept. 1980).
    8. de Bruyne, P. Developments in Signature Verification. Security Management Vo1. 22, No. 6 (1978) pp. 57 – 61.

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