THE INTENSITY AXIS OF SYMMETRY AND ITS APPLICATION TO IMAGE SEGMENTATION

In this paper, we present a new method for describing the shape of structures in grey-scale images, which is known as the intensity axis of symmetry (IAS). We describe the spatial and intensity variations of the image simultaneously rather than by the usual two-step process of 1) using intensity properties of the image to segment an image into regions and 2) describing the spatial shape of these regions. The result is an image shape description that is useful for a number of computer vision applications. Our method for computing this image shape description relies on minimizing an active surface functional that provides coherence in both the spatial and intensity dimensions while deforming into an axis of symmetry. Shape-based image segmentation is possible by identifying image regions associated with individual components of the IAS. The resulting image regions have geometric coherence and correspond well to visually meaningful objects in medical images.