Browse Prior Art Database

Digital Planimeter

IP.com Disclosure Number: IPCOM000095755D
Original Publication Date: 1964-Jun-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Funk, HL: AUTHOR

Abstract

A scanistor is used in a system which results in a digital planimeter for representing the area under a curve.

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Digital Planimeter

A scanistor is used in a system which results in a digital planimeter for representing the area under a curve.

There are two modes in which the planimeter can be operated. The first employs an opaque curve area. In the second mode, the curve is represented by a line. In the drawing, the first half of the curve is opaque and is associated with the first mode. The second half of the curve is a line and relates to the second mode. It is understood that in a given application one or the other modes is used, but not both as shown in the composite curves.

In the first mode, the curve is drawn on translucent paper 1 and the area under the curve is opaque. Light from source 2 is directed through paper 1 onto scanistor 3. Paper 1 is driven past stationary scanistor 3 in a horizontal direction such that the entire area of the paper is traversed. A ramp voltage from control unit 4 is applied to scanistor 3 once each time the drive increments the optical width of scanistor 3. Dark current pulses are counted in a counter in unit 4. The total residing in the counter at the end of a complete cycle is proportional to the area under the curve.

In the second mode, opaquing is not necessary where the curve is intercepted and detected by the ramp voltage which in turn stops the counter until the next scan. The image of the curve is projected on scanistor 3 and a scan is started at the lower edge of paper 1. Each light current pulse is counted until the, curve is i...