Figure 3: Coarse-to-fine comparison for the AME with VarEn (a) and the AME with SampEn (b) for discriminating the Invisible (red circle) and the Visible conditions (blue triangle) over multiple scales. The error bar refers to the standard error of mean. The leftmost red circle and blue triangle are the entropy measures of the raw data. For the AME with VarEn (a), significant differences occur at the 1st–6th scales, while the significant differences only occur at the 4th–6th scales for the AME with SampEn (b). The sign “*’’ refers to . The P values based on our VarEn and the SampEn along the coarse-to-fine scales are also compared (c), in which the horizontal black dotted line refers to the significance level ( ).