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Two sets of video frames from 2 different videos. (a) consists of the top 5 video frames and is from the first video. (b) consists of the bottom 5 video frames and is from the second video. (a) contains no flame, but (b) shows a flame being extinguished. The videos are aligned in time with their focal events for visual comparison. There is a white colored “x” overlaid at the position of the focus. Also shown is a 2 cm scale bar in the first frame.
