176519.fig.003a
(a)
176519.fig.003b
(b)
176519.fig.003c
(c)
176519.fig.003d
(d)
Figure 3: Histogram equalization for a typical glioblastoma multiforme grade IV AFM image. (a) Original AFM image composed of 512 × 512 pixels. The corresponding scan size was 100 × 100 μm2. The vertical bar shows differences in height in m. (b) Height histogram of the original data. (c) Equalized AFM image after the transformation step spreading out the height level histogram to a full dynamic range of 256 gray levels. (d) Corresponding equalized histogram.