Creating a compelling sense of presence and embodiment can enhance the user experience in virtual reality (VR). One method to accomplish this is through self-representation with embodied personalized avatars or video ...
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Diminished Reality (DR) allows for the selective removal or transformation of real-world objects from a user’s field of view. In certain cases, it becomes essential to revisit environments and observe them in their o...
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ISBN:
(数字)9798331514846
ISBN:
(纸本)9798331525637
Diminished Reality (DR) allows for the selective removal or transformation of real-world objects from a user’s field of view. In certain cases, it becomes essential to revisit environments and observe them in their original state. While Smartphone and Web-based approaches provide intuitive and convenient AR platforms, it also faces challenges like limited resources. This work introduces a DR system using Gaussian splats for real-time object removal on WebXR-enabled devices. We achieve up to 60 FPS while maintaining high visual fidelity, validated with different image quality metrics, offering a scalable solution for revisiting and manipulating temporally altered environments.
This study proposes a novel alternating optimization algorithm for bundle adjustment, a critical process in structure from motion methods. We introduce the inverse depth of each three-dimensional (3D) point as an augm...
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This study proposes a novel alternating optimization algorithm for bundle adjustment, a critical process in structure from motion methods. We introduce the inverse depth of each three-dimensional (3D) point as an augmented independent variable and develop a low-order polynomial error metric. Theoretically, the error can be adjusted to align closely with the re-projection error since it essentially acts as a re-weighted re-projection error. We decouple the bundle adjustment problem by breaking it down into three separate tasks: estimating the camera's pose, determining the 3D structure, and optionally estimating the camera's intrinsic parameter. Each task can be handled independently, either by camera or by point, allowing for easy distribution of computation. Camera pose estimation is a case of the absolute orientation problem, which can be globally solved in closed form. A linearization scheme is proposed for 3D point estimation, which allows the computation of the update direction and line search in closed form. Our algorithm proves to be efficient, reliable, and accurate, as demonstrated by experimental results that confirm its superiority over recent alternatives.
In engineering applications such as interactive design and simulation, some of the main object manipulations include feature interaction. Today's CAD systems provide object-oriented structures which can explicitly...
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In engineering applications such as interactive design and simulation, some of the main object manipulations include feature interaction. Today's CAD systems provide object-oriented structures which can explicitly represent functional and geometrical interactions among features. However, conventional interaction algorithms for manipulating these structures cannot cope with non-geometrical information such as feature functionality. Interaction among features plays an essential role in defining functionality. In this paper, a new method is described which focuses on implementation of an interaction mechanism for design and simulation. Two interaction categories are handled: (1) neighboring interaction, which is primarily geometrical (blending and trimming) and (2) functional interaction (machining). Since most interactions are performed in a sub-domain rather than in the entire domain, the advantage of the locality property is considered in both cases.
A new system has been developed for improving user interaction with CAD systems, particularly in the conceptual design stage. The system is based on interactive, part-by-part formation of a geometrical model using fre...
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A new system has been developed for improving user interaction with CAD systems, particularly in the conceptual design stage. The system is based on interactive, part-by-part formation of a geometrical model using freehand sketching. A single 2D inaccurate projection is entered in the form of a line drawing. The system analyzes and interprets the input and then reconstructs a 3D model of the object most likely to be represented by the sketch. This 3D model can be further manipulated or modified, and more parts can be sketched. This approach provides a fluent and intuitive tool for conceptual design. In the paper, the proposed system is presented and the basic ideas are discussed and exemplified.
Reconstructing a 3D sampled object into a computerized model is an essential part of reverse engineering. Applications such as casting and injection molding, however, also require a more abstract mid-surface represent...
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Reconstructing a 3D sampled object into a computerized model is an essential part of reverse engineering. Applications such as casting and injection molding, however, also require a more abstract mid-surface representation for analysis. Reconstructing a mid-surface from a thin object is known to be difficult and time consuming. In this paper, a reverse engineering method is proposed for simultaneously reconstructing a 3D object and its mid-surface. The object and the mid-surface models are created so that their mutual relations enable subsequent interactions between design and analysis, needed according to simulation results. The stages in modeling the reverse engineering object and its mid-surface are: (1) sampling and filtering points through a data reduction algorithm;(2) recognizing dominant pairs of boundaries;(3) parametrizing object boundaries and finding parametric correlations between them, according to mid-surface definition;and (4) reconstructing a 3D object and its mid-surface. Error analysis, results and examples will be demonstrated.
Point-based graphics has gained much attention as an alternative to polygon-based approaches because of its simplicity and flexibility. However, current point-based techniques do not provide a sufficient rendering qua...
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Point-based graphics has gained much attention as an alternative to polygon-based approaches because of its simplicity and flexibility. However, current point-based techniques do not provide a sufficient rendering quality for translucent materials such as human skin. In this paper, we propose a point-based framework with subsurface scattering of light, which is important to create the soft and semi-translucent appearance of human skin. To accurately simulate subsurface scattering in multilayered materials, we present splat-based diffusion to apply a linear combination of several Gaussian basis functions to each splat in object space. Compared to existing point-based approaches, our method offers a significantly improved visual quality in rendering human faces and provides a similar visual quality to polygon-based rendering using the texture space diffusion technique. We demonstrate the effectiveness of our approach in rendering scanned faces realistically.
We decompose the problem of the optimal multi-degree reduction of Bézier curves with corners constraint into two simpler subproblems, namely making high order interpolations at the two endpoints without degree re...
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We decompose the problem of the optimal multi-degree reduction of Bézier curves with corners constraint into two simpler subproblems, namely making high order interpolations at the two endpoints without degree reduction, and doing optimal degree reduction without making high order interpolations at the two endpoints. Further, we convert the second subproblem into multi-degree reduction of Jacobi polynomials. Then, we can easily derive the optimal solution using orthonormality of Jacobi polynomials and the least square method of unequally accurate measurement. This method of 'divide and conquer' has several advantages including maintaining high continuity at the two endpoints of the curve, doing multi-degree reduction only once, using explicit approximation expressions, estimating error in advance, low time cost, and high precision. More importantly, it is not only deduced simply and directly, but also can be easily extended to the degree reduction of surfaces. Finally, we present two examples to demonstrate the effectiveness of our algorithm.
We constructed a single C-Bezier curve with a shape parameter for G^2 joining two circular arcs. It was shown that an S-shaped transition curve, which is able to manage a broader scope about two circle radii than the ...
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We constructed a single C-Bezier curve with a shape parameter for G^2 joining two circular arcs. It was shown that an S-shaped transition curve, which is able to manage a broader scope about two circle radii than the Bezier curves, has no curvature extrema, while a C-shaped transition curve has a single curvature extremum. Regarding the two kinds of curves, specific algorithms were presented in detail, strict mathematical proofs were given, and the effectiveness of the method was shown by examples This method has the following three advantages： （1） the pattern is unified; （2） the parameter able to adjust the shape of the transition curve is available; （3） the transition curve is only a single segment, and the algorithm can be formulated as a low order equation to be solved for its positive root. These advantages make the method simple and easy to implement.
We present a novel approach for dealing with optimal approximate merging of two adjacent Bezier eurves with G^2-continuity. Instead of moving the control points, we minimize the distance between the original curves an...
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We present a novel approach for dealing with optimal approximate merging of two adjacent Bezier eurves with G^2-continuity. Instead of moving the control points, we minimize the distance between the original curves and the merged curve by taking advantage of matrix representation of Bezier curve＇s discrete structure, where the approximation error is measured by L2-norm. We use geometric information about the curves to generate the merged curve, and the approximation error is smaller. We can obtain control points of the merged curve regardless of the degrees of the two original curves. We also discuss the merged curve with point constraints. Numerical examples are provided to demonstrate the effectiveness of our algorithms.
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