Thermal image detector provided with means to eliminate fixed pattern noise
US5446283A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 10, 1993 |
| Grant date | Aug 29, 1995 |
| Priority date | — |
| Expiry date | Dec 10, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N23/23
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A thermal image detector and, more particularly, linear or matrix pyroelectric detectors. These detectors work differentially in successive phases of illumination and masking via a shutter that is synchronized with signal processing circuits. The detector generates differential measurement signals representing variations of pyroelectric signals recorded during a cycle comprising a masking phase and an illumination phase. To eliminate fixed pattern noise, it is proposed to make the measurements by difference between two successive cycles of masking and illumination, the order of the illumination/masking cycles being reversed between the two cycles but the measurements being made identically in both cycles. A memory records the signals during a cycle. A subtractor subtracts the signal of the current cycle from the signal recorded in the previous cycle.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.