Microscope Image Processing

8.3.2.1 Gradient

Observe that the morphological gradient (dilation minus erosion), previously

described for binary pictures, is extensible directly to grayscale morphology if

grayscale erosions and dilations are used. At each point the morphological

gradient yields the difference between the maximum and minimum values,

over the neighborhood, at the point determined by the flat structuring element.

The grayscale morphological gradient is often used as one step of a more

complex process, such as segmentation. For instance, Fig. 8.31b shows the

gradient of the yeast cells in Fig. 8.31a that we wish to segment. The segmenta-

tion of urology specimens in Fig. 8.30a and the chromosomes in Fig. 8.27a also

use gradient computation (Fig. 8.30b and Fig. 8.27b, ...