Introduction to Digital Image Processing

410 MORPHOLOGICAL IMAGE PROCESSING

Steinberg (26) has introduced the use of three-dimensional structuring elements

for gray scale image closing and opening operations. Although the concept is well

defined mathematically, it is simpler to describe in terms of a structural image

model. Consider a gray scale image to be modeled as an array of closely packed

square pegs, each of which is proportional in height to the amplitude of a corre-

sponding pixel. Then a three-dimensional structuring element, for example a sphere,

is placed over each peg. The bottom of the structuring element, as it is translated

over the peg array, forms another spatially discrete ...