Fig. 4.

Eight patches from two subsets in $\mathcal{S}$ and the associated AS of each patch. The patches on the left and right side correspond to tissue areas of $\sim 12\mathrm{mm}\times 12\mathrm{mm}$ and $25\mathrm{mm}\times 25\mathrm{mm}$, respectively. They had been extracted from the image corresponding to the central wavelength of 470 nm. In each spectrum plot, the $x$-axis denotes the wavelengths (470, 480, 511, 560, 580, 600, 660, and 700 nm) and the $y$-axis denotes the image intensity.