Table of Contents
Video voting examples
The video that the class watched
The class held up yellow cards when they perceived that the motion on the screen had been produced by physically moving the camera around. The class held up blue cards when they thought the motion was the product of panning or zooming the stationary camera.
The class watched an especially dramatic scene from the movie Once Upon a Time in the West.
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The same video with bar graphs showing the class' votes at every point in time
Please see this page for an explanation of how the relative number of cards held up was measured.
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Videos that were used to help make the video above
YUV decomposition of the video taken of the class voting
The original footage of the class holding up their cards has been blurred to obscure students' identities. Only the luminance (black-white) channel has been blurred, which leaves the colors from the cards with a sharp-edged appearance. The three panels at the right show the three YUV channels into which the footage can be split for further analysis.
The middle-right panel (the U plane) is analyzed to count the number of yellow and blue cards being held up during each frame of video of the class. These counts are used to draw the bar graph at the upper left.
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Distance-corrected, yellow-thresholded U plane
This video of the class voting shows the pixels that were detected to be yellow. Pixel brightness corresponds to distance away from the camera, which ensures that far away cards (which appear smaller) get counted equally with close up cards.
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