Computation of the Euler Number of a Binary Image Composed of Hexagonal Cells

ABSTRACTMost of the proposals to compute the Euler number of a binary image have been designed to work with imagescomposed of squared cells. Only a few of these methods (in the case of images composed of hexagonal cells) havebeen reported in literature, although it is known that images composed of hexagonal cells do not suffer from theproblems of connectivity frequently found in the case of images composed of squared cells. In this paper, a new wayto compute the Euler number (E) of a binary image composed of hexagonal cells is presented. For this, the perimeterP of the isolated regions in the image, their contact perimeter c P and the type T of a cell are used to obtain thisimportant invariant. The proposal can be used alone or in combination with other features to describe any binaryplanar shape composed of hexagonal pixels for its further recognition