Monitoring system for a predetermined field of view
US4554459A · kind A · utility
10Cited by
10References
8Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Dec 15, 1981 |
| Grant date | Nov 19, 1985 |
| Priority date | — |
| Expiry date | Dec 15, 2001 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B19/00
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A lift control system includes a spatial filter for producing a signal having various features, a discriminator for discriminating one or more features of the signal, and for producing a control signal when at least one of the features discriminated falls in a predetermined range, and active devices connected to the discriminator. The spatial filter is defined by a semi-spherical bowl having a plurality of openings or by a poly-face prism which is made from a plano-convex lens with its curved face so polished or cut as to have a plurality of flat faces.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.