Analyzing oriented textures through phase portraits

An attempt is made to develop a solution for signal-to-symbol transformation in the domain of flowlike or oriented texture. The geometric theory of differential equations is used to derive a symbol set based on the visual appearance of phase portraits. This theory provides a technique for describing textures both qualitatively and quantitatively. An attractive feature of this symbol set is that it is domain independent and makes no assumptions about the kind of texture that may be present. The computational framework for starting with a given oriented texture is provided, and its symbolic representation is derived. This is based on computing the orientation field for the texture and then using a nonlinear least-squares technique over successive windows to determine the changing spatial behavior of the texture. Results of the application of this technique to real texture images are presented.