US 3,944,988 AGranted

Image-display system interacting with light pen

AssigneeCompagnie Internationale Pour L'Informatique - C.I.I.

InventorJean Jacques Mayer

Life of this patent

Estimating the term…

Loading patent…

Abstract

Alphanumerical characters and other figures traced on an oscilloscope screen consist of elemental image components defined by code words which are called forth from a computer memory to actuate a function generator whose analog output is inscribed in a mosaic of a storage tube for orthogonal readout in the form of video pulses controlling the oscilloscope beam. A light pen placed against an illuminated spot of the oscilloscope screen picks up a light pulse which causes the inscription, on the same mosaic, of the code word giving rise to the image component whose trace is touched by the light pen. Different voltage levels of the code bits and of video pulses registered in superposed relationship on the storage mosaic enable their separation in a decoder upstream of the oscilloscope; the code word retrieved from the decoder is used to extinguish, intensify or otherwise mark the selected component within the displayed image.

A system for displaying composite images, comprising:

an oscilloscope provided with an intensity-control input for an electron beam thereof and with sweep means for the periodic deflection of said beam across a screen to produce thereon a luminous trace;
a light pen juxtaposable with a selected location on said screen for picking up light pulses from a displayed trace;
a computer provided with memory means for the storage of a multiplicity of code words identifying different components of an image to be traced on said screen;
function-generating means coupled to said memory means and responsive to a code word read out therefrom for producing an analog signal representing a corresponding image component;
storage means connected to said function-generating means for temporary loading by an analog signal generated in response to the readout of a code word from said memory means, said analog signal giving rise to a pattern of unipolar video pulses of a first amplitude in said storage means;
gating means controlled by said light pen for inscribing a selected code word, associatd with an image component touched by the light pen, in said storage means in the form of a pattern of code pulses having the same polarity as said video pulses, of a second amplitude different from said first amplitude, superimposed upon said pattern of video pulses;
scanning means synchronized with said sweep means for sequentially extracting the pulses of the superposed patterns from said storage means in the form of a unipolar pulse train with three distinct voltage levels besides zero;
decoder means connected to said storage means for receiving said unipolar pulse train therefrom and deriving from said three voltage levels thereof a video-pulse train delivered to said intensity-control input and a code-pulse train corresponding to the selected code word;
and
display-modification means connected to said decoder means for altering the appearance on said screen of the image component corresponding to said selected code word.

7 more elements

Abstract

Claims10