Abstract – The assessment of cranio-facial structures forms a part of orthodontic diagnosis. The medical procedure of marking landmarks on the standardized X-Ray of the face

and finding the distances and angles between the landmarks in order to calculate the facial proportions is known as Cephalometric Analysis. The traditional method of manually marking the landmarks on a tracing paper placed over the Cephalogram (standardized X-Ray of the

face) and making the scale measurements was vulnerable to errors. The evaluation prone errors were dealt by the semi-automatic software solution. This report talks about the project which aims at developing an application which can automatically and intelligently mark the Anatomic

landmark points on the digitally scanned cephalogram.

Index Terms – Orthodontics, Cephalogram, Cephalometry, Image Processing, Genetic Programming, Image Annotation.

INTRODUCTION 

The assessment of cranio-facial structures forms a part of orthodontic diagnosis. The earliest method used to assess facial proportions was by artistic standards with harmony,

symmetry end beauty as key points. It involved measurements of cranio-facial dimensions of skulls of dead persons. This method was not practical in living individuals due to the soft

tissue envelop which made direct measurements difficult and far less reliable.

The discovery of X-rays in 1895 by Roentgen revolutionized dentistry. It provided a method of obtaining the inner cranio-facial measurements with quite a bit of accuracy and reproducibility. In 1922 Paccini standardized the radiographic head images by positioning the subjects against a

film cassette at a distance of 2 meters from the X-ray tube [1].

In 1931 Boordbent in U.S.A. and Hofrath in Germany simultaneously presented a standardized cephalometric technique using a high powered X-ray machine and a head holder called Cephalostat [1]. The term cephalometrics is used to describe the analysis and measurements made on the cephalometric radiographs.

Types of Cephalograms:

• Lateral cephalogram: This provides a lateral view of the skull (Figure 1). It is taken with the head in a standardized reproducible position at a specified distance from the source of the X-ray.

• Frontal cephalogram: This provides an anteroposterior view of the skull (Figure 2).