Reproducible gray scale test chart for television cameras
US4575124A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 20, 1984 |
| Grant date | Mar 11, 1986 |
| Priority date | — |
| Expiry date | Mar 20, 2004 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N17/002
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A gray scale test chart for television cameras, in the form of either a transmittance chart or reflectance chart, includes one or more regions having selected gray values for calibrating or adjusting the output signal of the television camera, each gray value region being formed by an array of uniformly black dots arranged on a uniformly white background in a spatial frequency selected with respect to the resolution capability of the camera to produce an integrated output signal while being within the resolution capability of a photographic or other chart reproduction technique, the size of the dots in each region determining its gray value in combination with the spatial frequency or center-to-center spacing of the dots.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.