This paper introduces image segmentation as an important first task of any
image-analysis process. A seeded region-growing and -merging algorithm is c
reated to segment gray-scale and videophone-type colour images. The approac
h starts with a set of seed pixels, and from these grows regions by appendi
ng to each seed pixel those neighbouring pixels that satisfy a certain pred
icate. Small regions of far-away values are merged into neighbouring region
s. Regions of similar value are also merged. Homogeneity functions are intr
oduced for both gray-scale and colour images. The colour-image segmentation
approach utilizes the HSI (hue, saturation, intensity) colour space becaus
e of its close relation to the way in which people describe the perception
of colour.