System for detecting the edges of a moving object employing a photocell and an amplifier in the saturation mode
US4011447A · kind A · utility
Inventor
Key dates
| Filing date | Feb 9, 1976 |
| Grant date | Mar 8, 1977 |
| Priority date | — |
| Expiry date | Feb 9, 1996 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/342
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A system for detecting the edges of a moving object is disclosed having a high flux density light beam directed through two relatively long narrow light beam apertures and focused on a detector to saturate the output of the detector. When the moving object interrupts the light beam, the detector remains saturated until the moving object nearly intersects the entire light beam to thereby deactivate the detector at a precisely defined predetermined location within the light beam. The moving object reactivates the detector when its trailing edge intersects the light beam at a second precisely defined location within the light beam. An amplifier operating in saturation mode is coupled to the output of the detector to provide the added feature of switching its output when the object is at very precisely defined locations within the light beam. A computer system is coupled to the output of the amplifier to provide a pulse count to measure the time duration of the inactivity of the amplifier and to compute various physical parameters of the moving object such as velocity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.