ABSTRACT
In van Ginneken, ter Haar Romeny & Viergever 2001 and van Ginneken 2001 we find an overview of existing methods (up to 2001) to find rib boundaries. Those authors summarize what they call the classical approach as follows. Find the rib candidates using edge detection and fit geometrical models such as parabolas or ellipses (or a combination) to those candidates. The use of snakes and
1 INTRODUCTION
Tuberculosis (TB) remains worldwide a serious problem. In Portugal, TB incidence is 29.9/100.000 inhabitants, higher than the European Union average. Radiographic (x-ray) screening as a means of detecting active disease can play an important role in the prevention of this disease. Due to different reasons, experienced radiologists may misinterpret x-rays in more than a marginal percentage of the abnormal cases (Yoshida, Keserci & Doi 1998). Work on Computer Aided Diagnosis (CAD) systems has been done in the last two decades, frequently involving image processing and image classification (Doi, MacMahon, Giger & Hoffmann 1999, Katsuragawa & Doi 2007).
