3.2 Spongy mesophyll layer ((โครงสรา้ งใบ, leaf structure):
The near-infrared reflectance increase dramatically in the region from 0.71 to 1.2 m is due
to the internal scattering at the cell wall-air interfaces within the leaf (Gausmann et al., 1969).
The spongy mesophyll layer in a leaf controls the amount of near-infrared energy that is
reflected.
A water vapor absorption band exist for sensing in the near-infrared region is believed to be
0.74 - 0.90 m (Tucker, 1987).