Automatic detection of fluorescent flicker in video images

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 the 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 frequency analysis on the time-series of digital numbers to provide a first signal indicative of the spectral energy of the time-series of digital numbers at a flicker frequency band and a second signal indicative of the spectral energy of the time-series of digital numbers at 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.