The aim of the paper is to present a new processing procedure based on a computer vision methodology in order to reduce the uncertainty and the variability of the measure of the various angles of interest. In fact, for instance, for Scoliosis and spinal deformities analysis widely used parameters are the Cobb as well as Lordosis and Kyphosis angles. The measure of these parameters is usually manually obtained by the orthopaedic surgeon. This leads to a series of problems and to a great variability of the measurements obtained due to the quality of the x-ray measurements, the experience of the surgeon, the media used for the computation and so on. Gradient polygon method and image processing has been applied for extracting clinical features from x-ray images collected for Scoliosis analysis. To this aim a dedicated software has been developed in order to help clinicians to analyse, to interpret and to quantify spinal deformities in a more objective way, avoiding the manual computation of numerical parameters.