Patent ID: 7502054
Filing Date: 2009-03-10
Classification: H04N

Abstract:
1. A method for detecting the presence of flicker in video images comprising: obtaining a set of luminance data from each sampled image field of the video images; analyzing the set of luminance data to obtain a digital number characterizing a brightness characteristic of the set of luminance data; compiling a time-series of digital numbers over multiple sets of luminance data of multiple sampled image fields; performing a frequency analysis on the time-series of digital numbers to provide a first signal indicative of frequency components of the time-series of digital numbers in a flicker frequency band and a second signal indicative of the frequency components of the time-series of digital numbers in a non-flicker frequency band; computing a first spectral energy signal and a second spectral energy signal based on the first signal and the second signal respectively; computing a ratio of the first spectral energy signal to the second spectral energy signal, the ratio being a flicker detect indicator signal; accumulating multiple flicker detect indicator signals from multiple time-series of digital numbers, the accumulated flicker detect indicator signals having values greater than a first threshold; and generating a flicker present signal when the number of accumulated flicker detect indicator signals is greater than an entry value.