An algorithm for segmenting images using stick growing and merging is described, which consists of four major steps: stick initialisation, stick merging, subregion merging, and boundary modification. It is started from an initial decomposition of the image into small sticks and non-sticks. The small sticks are merged to obtain the initial subregions on the basis of homogeneity criteria. Then smaller subregions with only one stick are merged into larger subregions and subsequently all subregions are merged into regions according to the criteria. Finally, non-sticks and separate small sticks are merged and the degree of boundary roughness is reduced by boundary modification. The algorithm was successfully used to segment many types of complex food images including pizza, apple, pork and potato. (C) 2003 Elsevier Ltd. All rights reserved.