The effect of binarization on local motion scores for (A) F, (B) NF-S, (C) NF-T, and (D) G motions. SM scores were calculated for each movie segment based on raw luminance values (abscissa), and also following binarization with the threshold set at the overall shot median luminance (ordinate). No spatial downsampling was applied. A random sample of 500 shots from each movie is presented here. Movies were color coded as follows: (red) The 39 Steps, (blue) Anna Karenina, (green) A Night at the Opera, and (cyan) Mr. and Mrs. Smith (2005). The black line is the line of identity.