Automatic white balance control apparatus capable of performing white balance with a subject of a monochromatic color other than white
US5274440A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 5, 1992 |
| Grant date | Dec 28, 1993 |
| Priority date | — |
| Expiry date | Oct 5, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N23/88
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In an automatic white balance control apparatus which is less sensitive to a monochromic subject, color difference signals R-Y and B-Y are converted into digital values by A/D converters (20, 21). A quadrant determination circuit (22) determines for each digital color difference value to which quadrant of a two-dimensional coordinate system with an ordinate representing (R-Y) and an abscissa representing (B-Y) it belongs. Digital color difference values within one field are accumulated by accumulation device (28, 29, 30) per each quadrant. With respect to the digital color difference values (R-Y) wig& one field, digital difference values of pairs each one sampling period apart from each other are accumulated per each quadrant. The above two kinds of accumulations are carried out also with respect to the digital color difference values (B-Y) within one field. When the accumulated values of the two color difference values (R-Y) and (B-Y) within the respective quadrants are compared to control gains for R-Y and B-Y by a microprocessor (31), the accumulated value of the color differences in the quadrant, of which accumulated value of the digital difference values is small, is given a s…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.