Showing papers by "Ifeoma Nwogu published in 2007"

PDE-Based Enhancement of Low Quality Documents

Abstract: Partial Differential Equations are becoming one of the core tools for low-level image processing. They are especially functional in diffusion processes and variational models. In this paper, we exploit the regional smoothing that occurs in a nonlinear diffusion process and use this to enhance text in a degraded document image. The proposed smoothing method is robust when applied to either a highly corrupted text document or one with little degradation. The technique was tested on historical documents, carbon copies with highly varying grayscale backgrounds and on synthetic noisy documents. The PDE-based method far outperformed other industry-standard binarization techniques when compared quantitatively and qualitatively.

Fast Temporal Tracking and 3D Reconstruction of a Single Coronary Vessel

Abstract: Vessel extraction and vessel motion estimation from X-ray angiograms has been a challenging computer vision problem for several years. We have developed a fast and accurate method for extracting and tracking intravascular imaging data from X-ray angiograms. We accomplish this by reconstructing a moving 3D vessel, which contains more information than the static 2D snapshot image. Our approach involves identifying the vessel-of-interest in two biplane images, abstracting them into centerlines, and tracking them in ensuing images using deformable templates and graph techniques for optimization. When tested on fifteen patient datasets, the computational time was approximately 5 seconds per vessel per frame for vessels of length 80-100 mm.