Automated Optic Disk Boundary Detection by Modified Active Contour Model

Abstract

This paper presents a novel deformable-model-based algorithm for fully automated detection of optic disk boundary in fundus images. The proposed method improves and extends the original snake (deforming-only technique) in two aspects: clustering and smoothing update. The contour points are first self-separated into edge-point group or uncertain-point group by clustering after each deformation, and these contour points are then updated by different criteria based on different groups. The updating process combines both the local and global information of the contour to achieve the balance of contour stability and accuracy. The modifications make the proposed algorithm more accurate and robust to blood vessel occlusions, noises, ill-defined edges and fuzzy contour shapes. The comparative results show that the proposed method can estimate the disk boundaries of 100 test images closer to the groundtruth, as measured by mean distance to closest point (MDCP) <3 pixels, with the better success rate when compared to those obtained by gradient vector flow snake (GVF-snake) and modified active shape models (ASM).

Automatic Delineation of the Diaphragm in Computed Tomographic Images

“…A measure comparable to the Hausdorff distance was proposed by Xu et al 17 to evaluate quantitatively the degree of affinity between two sets. The measure, known as the MDCP of ground truth, computes the average distance to the closest point (DCP) between two sets; see Saha et al 28 for a related measure and discussion.…”

“…The method is evaluated using two methods that compare the results obtained with the contours drawn independently by a radiologist: the Hausdorff distance 16 and the mean distance to the closest point (MDCP) of ground truth. 17 The paper is organized as follows. First, the procedure used to segment the lungs is described, followed by a summary of the method for the extraction of the diaphragm-lung interface.…”

Video-Based Measuring of Quality Parameters for Tricuspid Xenograft Heart Valve Implants

“…Active contours or snakes are highly adaptable models and therefore widely used in the analysis of medical images [18], [22], [28]. A snake is a curve v(s) = [x(s), y(s)], s ∈ [0, 1], evolving over the spatial domain of an image under the influence of forces derived from internal and external energy terms to a position of minimum energy.…”

A Novel Adaptive Deformable Model for Automated Optic Disc and Cup Segmentation to Aid Glaucoma Diagnosis

“…Additionally, since pathological changes may arbitrarily deform the shape of the optic disc and also distort the course of blood vessels, the existing ASM-based approaches fail to accurately extract the object boundary with variation and irregularity and are influenced by blood vessel obscuration. The modified ACM approach as proposed by Xu and colleagues [35] have addressed optic disc segmentation problems due to vasculature occlusion and PPA by adjusting the uncertain cluster points of the contour. Nevertheless, they have also observed optic disc segmentation failures due to retinal atrophy or bright retinal lesions.…”