Automatic reference background monitoring network for a film processor
US4345831A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 3, 1980 |
| Grant date | Aug 24, 1982 |
| Priority date | — |
| Expiry date | Apr 3, 2000 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03D3/132
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A film processor having film transport rollers driven by a drive motor, a sensor for generating a signal representative of roller transport speed and a film density detector arrangement that includes a photodetector responsive to the intensity of a light source for generating a reference background level signal against which processed film is compared is characterized by a monitoring arrangement which periodically samples the photodetector output signal and adjusts a reference background level signal in accordance with fluctuations in the output of the scanner arrangement. To prevent the system from reacting to momentary perturbations in background level a moving weighted averaging technique is employed. The rate at which the reference background level signal is sampled is determined by the transport roller speed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.