Three-dimensional modelling and rendering of the human skeletal trunk from 2D radiographic images

The paper presents an original method for the 3D modelling and rendering of the human spine, rib cage and pelvis for the study of spinal deformities. It uses an adaptation of the standard close-range photogrammetry method called Direct Linear Transformation to infer the 3D co-ordinates of anatomical landmarks from 3 radiographic images of the subject´s trunk. It then deforms in 3D high-resolution anatomical primitives (reference bones) obtained by ct-scan reconstruction of a dry specimen. Free-form deformation is calculated using a new formulation of dual kriging equations. In-vivo validation of this method on 40 scoliotic vertebrae gives an overall accuracy of 3.5±4.1 mm, making it an adequate tool for diagnosis and mechanical analysis purposes. This new method can also find applications in biological and synthetic actors real time tracking and animation