Figure 3

Smoothing of nuclear staining as used for measuring differentiation. (A) Illustration of the smoothing process. The band corrected image of nuclear staining is smoothed by averaging over a distance and curvature dependent neighbourhood (filter matrix). In the input and output image three corresponding different epidermal locations are marked, respectively. (B) The mask of all nuclei when superimposed on the smoothed image demonstrates that smoothing removes the original contrast of the nuclei with respect to their environment. (C) Profile of nuclei density measured against the relative distance to connective tissue averaged over a representative set of tissue sections. The blue curve shows the gradient calculated from the original native image of nuclear staining. The red curve is computed on the image after adjusting intensity values in the area of basal lamina and subsequent smoothing. (D) Analysis of the nuclei density in an exemplary tissue sample. The loss of DAPI intensity throughout the complete tissue (blue) results only partly from the loss of DAPI inside each nucleus (red). The ratio of the blue and red graph (green) shows the impact of cytoplasmic growth and nuclear degradation on the loss of DAPI intensity throughout the tissue. At 100% distance to the connective tissue, the loss of DAPI intensity per epidermal area can be attributed almost entirely to cytoplasmic growth and nuclear degradation