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Automatic detection of fluorescent flicker in video images

  • US 7,502,054 B2
  • Filed: 12/20/2004
  • Issued: 03/10/2009
  • Est. Priority Date: 12/20/2004
  • Status: Active Grant
First Claim
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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.

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