Automatic detection of fluorescent flicker in video images
US7502054B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 20, 2004 |
| Grant date | Mar 10, 2009 |
| Priority date | — |
| Expiry date | Dec 6, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N23/745
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method for detecting the presence of flicker in video images includes obtaining luminance data from sampled image fields and analyzing the luminance data to obtain a digital number characterizing the brightness of the luminance data. Frequency analysis is performed on a time-series of digital numbers collected over multiple sampled image fields to provide a signal indicative of the spectral energy at a flicker frequency band and a signal indicative of the spectral energy at a non-flicker frequency band. A ratio of the two spectral energy signals is computed as the flicker detect indicator. Multiple flicker detect indicators are accumulated to generate a flicker present signal. In one embodiment, the flicker detect indicator is accumulated only when the ratio has a value greater than a first threshold and the flicker present signal is asserted only when the number of flicker detect indicator signals accumulated exceeds an entry value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.