I agree with Stephen's comment. Since the authors claim that the novelty of their method is in the use of motion, the experimental results need to be less ambiguous: one ROC curve concludes that motion helps (fig 9) while the other says motion does not have an effect (fig 8). Thus, as it stands, the paper is inconclusive. It may have helped to determine in more detail the reason(s), if any, for the different results.