Figure 2

The mechanisms of coating penetration distance quantification (a). The three-dimensional X-ray scanning image result; determination of axis; pink arrow indicates the longitudinal axis (6 lines) and orange line indicates the tangential axis (5 lines; orange number 1–5) of coated wood; the green bar indicating the air between the specimens (b). Two-dimensional image from one of the tangential axis in transverse section; the pink arrow indicates longitudinal axis; orange square indicating the line that analyze using ImageJ (c). The grey value plot profile of the orange square.