The primary objective of this work is to explore various approximation properties of Stancu variant generalized (lambda, mu)-Bernstein operators. Various moment estimates are analyzed, and several aspects of local dir...
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The primary objective of this work is to explore various approximation properties of Stancu variant generalized (lambda, mu)-Bernstein operators. Various moment estimates are analyzed, and several aspects of local direct approximation theorems are investigated. Additionally, further approximation features of newly defined operators are delved into, such as the Voronovskaya-type asymptotic theorem and pointwise estimates. By comparing the proposed operator graphically and numerically with some linear positive operators known in the literature, it is evident that much better approximation results are achieved in terms of convergence behavior, calculation efficiency, and consistency. Finally, the newly defined operators are used to obtain a numerical solution for a special case of the fractional Volterra integral equation of the second kind.
Kinematic tracking of native anatomy in dynamic radiography facilitates understanding of in vivo movement. Tracking is performed using model-image registration, which involves estimating 6 degree-of-freedom poses of a...
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Kinematic tracking of native anatomy in dynamic radiography facilitates understanding of in vivo movement. Tracking is performed using model-image registration, which involves estimating 6 degree-of-freedom poses of anatomic structures by comparing captured radiographs to dynamically rendered images of digital models. This procedure can produce accurate pose estimates of native anatomy, but computational efficiency remains a concern. A key source of latency in model-image registration is the iterative rendering of digitally reconstructed radiographs, required for evaluation of candidate poses. This technical note introduces an efficient algorithm for rendering digitally reconstructed radiographs. The proposed method is shown to accelerate rendering speeds by up to 50% compared to a baseline method which is commonly used in registration frameworks. Efficient rendering of digitally reconstructed radiographs may enhance the overall viability of model-image registration for use in kinematic tracking, and may contribute to bringing this technology closer to adoption in clinical settings.
Three-dimensional mesh compression is vital to support advances in many scenarios, such as 3D web-based applications. Existing 3D mesh methods usually require complex data structures and time-consuming processing. Giv...
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Three-dimensional mesh compression is vital to support advances in many scenarios, such as 3D web-based applications. Existing 3D mesh methods usually require complex data structures and time-consuming processing. Given a mesh represented by its vertices and triangular faces, we present a novel, fast, and straightforward encoding algorithm. Our method encodes the mesh connectivity data based on an upper triangular matrix which is easily recovered by its underlying decoding process. Our technique encodes the mesh edges in linear time without losing any face in the process. Results show that our method provides a connectivity compression rate of 55.29 and an average total compression rate of 27.09. Furthermore, our approach achieves, on average, a similar compressing rate of state-of-the-art algorithms, such as OpenCTM, which considers geometry and connectivity, while our approach considers only their connectivity.
Stylized avatars are common virtual representations used in VR to support interaction and communication between remote collaborators. However, explicit expressions are notoriously difficult to create, mainly because m...
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Stylized avatars are common virtual representations used in VR to support interaction and communication between remote collaborators. However, explicit expressions are notoriously difficult to create, mainly because most current methods rely on geometric markers and features modeled for human faces, not stylized avatar faces. To cope with the challenge of emotional and expressive generating talking avatars, we build the Emotional Talking Avatar Dataset which is a talking-face video corpus featuring 6 different stylized characters talking with 7 different emotions. Together with the dataset, we also release an emotional talking avatar generation method which enables the manipulation of emotion. We validated the effectiveness of our dataset and our method in generating audio based puppetry examples, including comparisons to state-of-the-art techniques and a user study. Finally, various applications of this method are discussed in the context of animating avatars in VR.
To determine the technologies at the origin of computer graphics, this analysis focuses on prior art documents cited in patent publications from 1940s and 1950s technologies that, together, led to the emergence of com...
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To determine the technologies at the origin of computer graphics, this analysis focuses on prior art documents cited in patent publications from 1940s and 1950s technologies that, together, led to the emergence of computer graphics in the 1960s. The key finding is that, in addition to computing and television, computer graphics has deep roots in radar-related technologies and aircraft instrumentation.
This article introduces a new method for simulating synthetic aperture sonar (SAS) raw coherent echo data, which is orders of magnitude faster than the commonly used point and facet diffraction models. The new approac...
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This article introduces a new method for simulating synthetic aperture sonar (SAS) raw coherent echo data, which is orders of magnitude faster than the commonly used point and facet diffraction models. The new approach uses Fourier wavefield generation and propagation in combination with a highly optimized optical rendering engine. It has been shown to produce a quantifiably similar quality of data and data products (i.e., images and spectra) to a point-diffraction model, capturing the important coherent wave physics (including diffraction, speckle, aspect-dependence, and layover) as well as effects of the SAS processing chain (including image focusing errors and artifacts). This new simulation capability may be an enabler for augmenting data sets with physically accurate and diverse synthetic data for robust machine learning.
This study aimed to evaluate the performance of three artificial intelligence (AI) image synthesis models, Dall-E 2, Stable Diffusion, and Midjourney, in generating urban design imagery based on scene descriptions. A ...
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This study aimed to evaluate the performance of three artificial intelligence (AI) image synthesis models, Dall-E 2, Stable Diffusion, and Midjourney, in generating urban design imagery based on scene descriptions. A total of 240 images were generated and evaluated by two independent professional evaluators using an adapted sensibleness and specificity average metric. The results showed significant differences between the three AI models, as well as differing scores across urban scenes, suggesting that some projects and design elements may be more challenging for AI art generators to represent visually. Analysis of individual design elements showed high accuracy in common features like skyscrapers and lawns, but less frequency in depicting unique elements such as sculptures and transit stops. AI-generated urban designs have potential applications in the early stages of exploration when rapid ideation and visual brainstorming are key. Future research could broaden the style range and include more diverse evaluative metrics. The study aims to guide the development of AI models for more nuanced and inclusive urban design applications, enhancing tools for architects and urban planners.
We present a novel framework for reconstructing fluid dynamics in real-life scenarios. Our approach leverages sparse view images and incorporates physical priors across long series of frames, resulting in reconstructe...
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We present a novel framework for reconstructing fluid dynamics in real-life scenarios. Our approach leverages sparse view images and incorporates physical priors across long series of frames, resulting in reconstructed fluids with enhanced physical consistency. Unlike previous methods, we utilize a differentiable fluid simulator (DFS) and a differentiable renderer (DR) to exploit global physical priors, reducing reconstruction errors without the need for manual regularization coefficients. We introduce divergence-free Laplacian eigenfunctions (div-free LE) as velocity bases, improving computational efficiency and memory usage. By employing gradient-related strategies, we achieve better convergence and superior results. Extensive experiments demonstrate the effectiveness of our method, showcasing improved reconstruction quality and computational efficiency compared to existing approaches. We validate our approach using both synthetic and real data, highlighting its practical potential.
The polygonal contact model is an established contact algorithm for multibody dynamics based on polygonal surfaces. Some guidance for its practical use is presented. In particular, assignment and discretization of the...
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The polygonal contact model is an established contact algorithm for multibody dynamics based on polygonal surfaces. Some guidance for its practical use is presented. In particular, assignment and discretization of the surface meshes are discussed with regard to correct results and optimal efficiency. Moreover, notes on stiffness and damping parameters are *** improved implementation of the polygonal contact model is introduced. The new algorithm goes without quite complicated intersection construction steps. As a consequence, it is less complex, more robust and usually more efficient than the classic *** examples of varied complexity demonstrate both notes on usage and improved implementation of the polygonal contact model.
While signed distance fields (SDFs) in theory offer infinite level of detail, they are typically rendered using the sphere tracing algorithm at finite resolutions, which causes the common rasterized image synthesis pr...
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While signed distance fields (SDFs) in theory offer infinite level of detail, they are typically rendered using the sphere tracing algorithm at finite resolutions, which causes the common rasterized image synthesis problem of aliasing. Most existing optimized antialiasing solutions rely on polygon mesh representations;SDF-based geometry can only be directly antialiased with the computationally expensive supersampling or with post-processing filters that may produce undesirable blurriness and ghosting. In this work, we present cone-traced supersampling (CTSS), an efficient and robust spatial antialiasing solution that naturally complements the sphere tracing algorithm, does not require casting additional rays per pixel or offline pre-filtering, and can be easily implemented in existing real-time SDF renderers. CTSS performs supersampling along the traced ray near surfaces with partial visibility - object contours - identified by evaluating cone intersections within a pixel's view frustum. We further introduce subpixel edge reconstruction (SER), a technique that extends CTSS to locate and resolve complex pixels with geometric edges in relatively flat regions, which are otherwise undetected by cone intersections. Our combined solution relies on a specialized sampling strategy to minimize the number of shading computations and correlates sample visibility to aggregate the samples. With comparable antialiasing quality at significantly lower computational cost, CTSS is a reliable practical alternative to conventional supersampling.
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