Gregory G. Slabaugh

Georgia Institute of Technology, Atlanta, GA, United States

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Publications (26)8.71 Total impact

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    Gözde B. Ünal · Delphine Nain · Gregory G. Slabaugh · Tong Fang
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    ABSTRACT: 3D shape modeling is a crucial component of rapid prototyping systems that customize shapes of implants and prosthetic devices to a patient’s anatomy. In this paper, we present a solution to the problem of customized 3D shape modeling using a statistical shape analysis framework. We design a novel method to learn the relationship between two classes of shapes, which are related by certain operations or transformation. The two associated shape classes are represented in a lower dimensional manifold, and the reduced set of parameters obtained in this subspace is utilized in an estimation, which is exemplified by a multivariate regression in this paper. We demonstrate our method with a felicitous application to the estimation of customized hearing aid devices.
    Full-text · Article · Jan 2011 · Computer-Aided Design
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    Gregory G. Slabaugh · Brian Whited · Jarek Rossignac · Tong Fang · Gozde B. Unal
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    ABSTRACT: We present an approach to compute a smooth, interpolating skin of an ordered set of 3D balls. By construction, the skin is constrained to be C1 continuous, and for each ball, it is tangent to the ball along a circle of contact. Using an energy formulation, we derive differential equations that are designed to minimize the skin’s surface area, mean curvature, or convex combination of both. Given an initial skin, we update the skin’s parametric representation using the differential equations until convergence occurs. We demonstrate the method’s usefulness in generating interpolating skins of balls of different sizes and in various configurations.
    Full-text · Article · Jan 2010
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    Gozde B. Unal · S. Bucher · Stephane G. Carlier · Gregory G. Slabaugh · Tong Fang · K. Tanaka

    Full-text · Article · Jan 2008
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    Full-text · Article · Jan 2008
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    Gregory G. Slabaugh · Gozde B. Unal · Tong Fang · Jarek Rossignac · Brian Whited
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    ABSTRACT: This paper considers the problem of computing an interpolating skin of a ordered set of discrete 2D balls. By construction, the skin is constrained to be C 1 continuous, and for each ball, it touches the ball at a point and is tangent to the ball at the point of contact. Using an energy formulation, we derive differential equations that are designed to minimize the skin’s arc length, curvature, or convex combination of both. Given an initial skin, we update the skin’s parametric representation using the differential equations until convergence occurs. We demonstrate the method’s usefulness in generating interpolating skins of balls of different sizes and in various configurations.
    Full-text · Conference Paper · Jan 2008
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    Gozde B. Unal · Delphine Nain · Gregory G. Slabaugh · Tong Fang
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    ABSTRACT: D shape modeling is a crucial component of rapid prototyping systems that customize shapes of implants and prosthetic devices to a patient's anatomy. In this paper, we present a solution to the problem of customized 3D shape modeling using a statistical shape analysis framework. We design a novel method to learn the relationship between two classes of shapes, which are related by certain operations or transformation. The two associated shape classes are represented in a lower di- mensional manifold, and the reduced set of parameters obtained in this subspace is utilized in an estimation, which is exemplified by a multivariate regression in this paper. We demonstrate our method with a felicitous application to estimation of cus- tomized hearing aid devices.
    Preview · Conference Paper · Jan 2008
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    Gregory G. Slabaugh · Koon Kong · Gozde B. Unal · Tong Fang
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    ABSTRACT: We present a novel method to track a guidewire in cardiac x-ray video. Using variational calculus, we derive differential equations that deform a spline, subject to intrinsic and extrinsic forces, so that it matches the image data, remains smooth, and preserves an a priori length. We analytically derive these equations from first principles, and show how they include tangential terms, which we include in our model. To address the poor contrast often observed in x-ray video, we propose using phase congruency as an image-based feature. Experimental results demonstrate the success of the method in tracking guidewires in low contrast x-ray video.
    Preview · Conference Paper · Oct 2007
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    ABSTRACT: Segmentation of regions of interest in an image has important applications in medical image analysis, particularly in computer aided diagnosis. Segmentation can enable further quantitative analysis of anatomical structures. We present efficient image segmentation schemes based on the solution of distinct partial differential equations (PDEs). For each known image region, a PDE is solved, the solution of which locally represents the weighted distance from a region known to have a certain segmentation label. To achieve this goal, we propose the use of two separate PDEs, the Eikonal equation and a diffusion equation. In each method, the segmentation labels are obtained by a competition criterion between the solutions to the PDEs corresponding to each region. We discuss how each method applies the concept of information propagation from the labelled image regions to the unknown image regions. Experimental results are presented on magnetic resonance, computed tomography, and ultrasound images and for both two-region and multi-region segmentation problems. These results demonstrate the high level of efficiency as well as the accuracy of the proposed methods.
    Full-text · Article · Sep 2007 · International Journal of Computer Mathematics
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    Gozde B. Unal · Anthony J. Yezzi · Stefano Soatto · Gregory G. Slabaugh

    Preview · Article · Jan 2007
  • Alexander Zouhar · Tong Fang · Gozde B. Unal · Gregory G. Slabaugh · Hui Xie · Fred McBagonluri

    No preview · Conference Paper · Jan 2006
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    Huy-Nam Doan · Gregory G. Slabaugh · Gozde B. Unal · Tong Fang
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    ABSTRACT: We present a semi-automatic segmentation technique of the anatomical structures of the brain: cerebrum, cerebellum, and brain stem. The method uses graph cuts segmentation with an anatomic template for initialization. First, a skull stripping procedure is applied to remove non-brain tissues. Then, the segmentation is done hierarchically by first, extracting first the cerebrum from the brain, and then from the remaining volume the cerebellum and the brain stem are separated. This method is fast and can separate different anatomical structures of the brain in spite of weak boundaries. We describe our approach and present experimental results demonstrating its usefulness.
    Full-text · Conference Paper · Jan 2006
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    ABSTRACT: In this paper, we present efficient and simple image segmentations based on the solution of two separate Eikonal equations, each originating from a different region. Distance functions from the interior and exterior regions are computed, and final segmentation labels are determined by a competition criterion between the distance functions. We also consider applying a diffusion partial differential equation (PDE) based method to propagate information in a manner inspired by the information propagation feature of the Eikonal equation. Experimental results are presented in a particular medical image segmentation application, and demonstrate the proposed methods.
    No preview · Conference Paper · Jan 2006
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    Amer Abufadel · Gregory G. Slabaugh · Gozde B. Unal · Li Zhang · Benjamin Odry
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    ABSTRACT: This paper presents a fast and efficient method to determine intervertebral disk orientation in a magnetic resonance (MR) image of the spine. The algorithm originates from active contour theory and enforces a shape constraint to avoid leaks through weak or non-existent boundaries. The method represents a vertebra as a rectangle, modeled as a semi-affine transformation applied to the unit square. A regional flow integrated along the rectangle's perimeter updates the rectangle's transformation to achieve the segmentation. Further constraints are added so that adjacent rectangles have similar orientation and scale. The orientation of a disk is then inferred from its adjacent vertebrae. Experiments show that the method is fast and effective in detecting the correct intervertebral disk orientation, which is used for transverse image planning
    Full-text · Conference Paper · Jan 2006
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    Gregory G. Slabaugh · Viorel Mihalef · Gozde B. Unal
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    ABSTRACT: This paper presents a simple and efficient method of forming a 3D text label on a 3D triangulated surface. The label is formed by projecting the 2D contours that define the text silhouette onto the triangulated surface, forming 3D contour paths. Surface polygons upon which the 3D contour paths lie are retriangulated using a novel approach that forms a polyline defining the region outside the contour. This algorithm produces labeled 3D surfaces that conform to the specifications of the STL format, making them suitable for fabrication by a rapid prototyping machine. We demonstrate the effectiveness of the algorithm in forming flat and extruded labels on non-trivial surfaces.
    Full-text · Conference Paper · Jun 2005
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    ABSTRACT: In this paper, we present methods for 3D volumetric reconstruction of visual scenes photographed by multiple calibrated cameras placed at arbitrary viewpoints. Our goal is to generate a D model that can be rendered to syn- thesize new photo-realistic views of the scene. We improve upon existing voxel coloring / space carving approaches by introducing new ways to compute visibility and photo- consistency, as well as model infinitely large scenes. In particular, we describe a visibility approach that uses all possible color information from the photographs during reconstruction, photo-consistency measures that are more robust and/or require less manual intervention, and a volu- metric warping method for application of these reconstruc- tion methods to large-scale scenes.
    Full-text · Article · May 2004 · International Journal of Computer Vision
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    ABSTRACT: In this paper, we present methods for 3D volumetric reconstruction of visual scenes photographed by multiple calibrated cameras placed at arbitrary viewpoints. Our goal is to generate a 3D model that can be rendered to synthesize new photo-realistic views of the scene. We improve upon existing voxel coloring / space carving approaches by introducing new ways to compute visibility and photoconsistency, as well as model infinitely large scenes. In particular, we describe a visibility approach that uses all possible color information from the photographs during reconstruction, photo-consistency measures that are more robust and/or require less manual intervention, and a volumetric warping method for application of these reconstruction methods to large-scale scenes.
    Full-text · Article · Oct 2003
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    Gregory G. Slabaugh · Ronald W. Schafer · Mat C. Hans
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    ABSTRACT: We present an efficient image-based rendering algorithm that generates views of a scene's photo hull. The photo hull is the largest 3D shape that is photo-consistent with photographs taken of the scene from multiple viewpoints. Our algorithm, image-based photo hulls (IBPH), like the image-based visual hulls (IBVH) algorithm from Matusik et al. on which it is based, takes advantage of epipolar geometry to efficiently reconstruct the geometry and visibility of a scene. Our IBPH algorithm differs from IBVH in that it utilizes the color information of the images to identify scene geometry. These additional color constraints result in more accurately reconstructed geometry, which often projects to better synthesized virtual views of the scene. We demonstrate our algorithm running in a realtime 3D telepresence application using video data acquired from multiple viewpoints.
    Preview · Article · Oct 2003 · Real-Time Imaging
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    G.G. Slabaugh · R.W. Schafer · M.C. Hans
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    ABSTRACT: We present a multi-resolution space carving algorithm that reconstructs a 3D model of a visual scene photographed by a calibrated digital camera placed at multiple viewpoints. Our approach employs a level set framework for reconstructing the scene. Unlike most standard space carving approaches, our level set approach produces a smooth reconstruction composed of manifold surfaces. Our method outputs a polygonal model, instead of a collection of voxels. We texture-map the reconstructed geometry using the photographs, and then render the model to produce photo-realistic new views of the scene.
    Preview · Conference Paper · Feb 2002
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    Preview · Conference Paper · Jan 2002
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    ABSTRACT: Voxel coloring methods reconstruct a three-dimensional volumetric surface model from a set of calibrated twodimensional photographs taken of a scene. In this paper, we recast voxel coloring as an optimization problem, the solution of which strives to minimize reprojection error, which measures how well projections of the reconstructed scene reproduce the photographs. The reprojection error, defined in image space, guides the refinement of the scene reconstruction in object space. Unlike previous voxel coloring methods, ours makes better use of all color information from all viewpoints, and thereby produces higher quality reconstructions. In addition, it allows voxels to be added to, not just removed from, the scene at any time during reconstruction. We examine methods to minimize the reprojection error, including greedy and simulated annealing techniques. Reconstructions of both synthetic and real scenes are presented and analyzed. 1 Introduction Voxel coloring methods [1] [7] [11] r...
    Full-text · Article · Jan 2001