The comparison surface (1.91 deg×1.91 deg) was presented in the same location outside of the room scene and surrounded by a black background (Figure 5).
The figures inhabit a space that is defined by the solid forms of the figures themselves and is limited by the background plane.
Both Figures 3 and 4c,f show the extraction results by the background subtraction method we presented above.
In the background, other figures rest outside the house.
Figure 4 shows the noise in the PET imaging volumes, quantified by both the background variability (Eq. 3, Fig. 4a) and the signal intensity in the cold lung insert normalized by the true background activity (Eq. 4, Fig. 4b).
Perhaps figure/ground considerations could be invoked to provide an answer in this second case, based on the principle that the boundary is always owned by the figure — the background is topologically open (Jackendoff 1987, App. B).
Instead we indicate the background level in Figure 1C by a red line.
Erase the rest of the background from the figure.
A lively jazz band in the background guides the figures.
Figure 4 In both figures, the background distribution is well fitted by a Gaussian curve, represented here as a red thick line.
