Picture quality testing method and apparatus for color cathode-ray tube
US4963828A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 13, 1989 |
| Grant date | Oct 16, 1990 |
| Priority date | — |
| Expiry date | Feb 13, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R31/257
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
For the purpose of automated evaluation of white uniformity, the apparatus comprises a color television camera for picking up an image of white color displayed on the color cathode-ray tube, a circuit for separating color signals from the output signal of the color television camera, A/D converters for converting the analog color signals into digital color signals, memories for storing the digital color signals, and a computer for analyzing the contents of the memories. A nonuniform color portion is extracted from the color distribution of the display on the cathode-ray tube, and quantities of various features of the nonuniform color portion, for example, the hue, saturation and area of the nonuniform color portion and the degree of change in the saturation at the marginal edge contour of the nonuniform color portion are calculated by the computer to provide parameters used for evaluation of the white uniformity. Then, the white uniformity of the display on the color cathode-ray tube is quantitatively evaluated on the basis of the previous experimental, visually evaulated relation between the individual parameters and the results of visual evaluation of the white uniformity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.