1. An apparatus comprising: an input for receiving a video signal comprising a first image and a second image wherein said second image is received after said first image; a processor operative to determine a first probable location of a first caption within a first image, analyze said first image to identify a first region of said first image comprising said probable location of said first caption, determine a second probable location of a second caption with a second image, analyze said second image to identify a second region of said second image comprising said probable location of said second caption, determine a spatial overlap between said first region and said second region, and generate a data representing said spatial overlap. an output for coupling said data to a video processor.