Figure 4. Parameter tuning.

The root mean square (RMS) deformation field error (mm) over a cortical gray matter (GM) mask in a single axial slice through the center of the brain across the 39 testing subjects as a function of the ridge regression smoothness parameter α for different values of the Gaussian smoothing parameter σ (in mm). Left: Results for the 0–20 minute PiB-PET. Right: Results for the 50–70 minute PiB-PET. For references to color, the reader is referred to the web version of this article.