Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

Monitor Selection Technique for Light Pen Functions

IP.com Disclosure Number: IPCOM000039704D
Original Publication Date: 1987-Jul-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 2 page(s) / 55K

Publishing Venue

IBM

Related People

Dingsor, AD: AUTHOR

Abstract

This article describes a technique for determining which of several adjacent monitors with which a single light pen is being used. The technique, performed in software, eliminates the need for a multi- position hardware switch which would otherwise be used to perform the same function. The technique is employed in a video conferencing system having a plurality (usually 3 or 4) monitors, all of which derive synch signals from a system clock. The technique permits the user of a light pen to work with any of the monitors. Referring to the flow chart, monitor selection is initiated when the user touches the light pen to any of the monitors. The closure of a switch within the light pen is an indication that the user wishes to perform light pen functions at one of the monitors.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 73% of the total text.

Page 1 of 2

Monitor Selection Technique for Light Pen Functions

This article describes a technique for determining which of several adjacent monitors with which a single light pen is being used. The technique, performed in software, eliminates the need for a multi- position hardware switch which would otherwise be used to perform the same function. The technique is employed in a video conferencing system having a plurality (usually 3 or 4) monitors, all of which derive synch signals from a system clock. The technique permits the user of a light pen to work with any of the monitors. Referring to the flow chart, monitor selection is initiated when the user touches the light pen to any of the monitors. The closure of a switch within the light pen is an indication that the user wishes to perform light pen functions at one of the monitors. Since all of the monitors are synchronized to the same system clock, normal light pen operations permit the system to detemine the X, Y coordinates of the target region TR being touched by the monitor. However, at this point the system does not know which of the several adjacent monitors is being touched. Beginning at the first of the monitors, the system saves the image data in the target region TR in a memory. The monitor is then driven under software control to change the pels in the target region TR to all black. A check is made to determine whether the output of the light pen changes. If it does not, the system assumes the light pen is not...