The smoothed pressure map (right image of Fig. 4) contains
pressure artifacts (at the top left and right corners of the image)
due to the corners of pressure sensor sheets being wrapped
around the chair. Since these artifacts are common to all
pressure maps, their removal is not necessary. Finally, the
values of pressure readings are normalized, separately for the
seatpan and the backrest maps. The rest of this paper assumes
that all pressure maps have gone through the aforementioned
preprocessing procedures.