Three dimensional concentration index-a local feature for analyzing three dimensional digital line patterns and its application to chest X-ray CT images

We propose a local feature called three dimensional (3D) concentration index for analyzing line texture patterns in 3D space. This feature can be used for evaluating quantitatively local concentration of lines at each point of a 3D line pattern. In the paper, simulations using artificial patterns are performed to examine basic properties of the index. The index is also applied to patterns of vessels and bronchi extracted from practical chest X-ray CT images. As a result, it is shown that the 3D concentration index can be used to quantify the degree of convergence of vessels and bronchi to a tumor