In this paper, an image processing technique has been employed to quantitatively analyse various fractured surfaces of rubber and measure roughness. The image surfaces are represented in terms of a closed set of orthogonal polynomials. The significant orthogonal effects are measured and combined to represent the local texture, called pronum. The frequency of occurrence of the pronums is the prospectrum, a global descriptor. A few statistical parameters have been calculated from the prospectrum and correlated to the roughness of the fractured surfaces. Using the image processing technique, the laborious procedure involved in quantification, especially of irregular microfeatures, has been shown to be overcome.