- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Scalable appearance filtering for complex lighting effects
摘要： Realistic rendering with materials that exhibit high-frequency spatial variation remains a challenge, as eliminating spatial and temporal aliasing requires prohibitively high sampling rates. Recent work has made the problem more tractable, however existing methods remain prohibitively expensive when using large environmental lights and/or (correctly filtered) global illumination. We present an appearance model with explicit high-frequency micro-normal variation, and a filtering approach that scales to multi-dimensional shading integrals. By combining a novel and compact half-vector histogram scheme with a directional basis expansion, we accurately compute the integral of filtered high-frequency reflectance over large lights with angularly varying emission. Our approach is scalable, rendering images indistinguishable from ground truth at over 10× the speed of the state-of-the-art and with only 15% the memory footprint. When filtering appearance with global illumination, we outperform the state-of-the-art by ～ 30×.
关键词： glints,normal maps,summed area tables,spherical harmonics
更新于2025-09-23 15:23:52
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Improvement of Ohmic Behavior of Back Contact in ZnSnP <sub/>2</sub> Solar Cells by Inserting Cu <sub/>3</sub> P
摘要： We propose a sampling scheme that can perfectly re- construct a collection of spikes on the sphere from samples of their lowpass-?ltered observations. Central to our algorithm is a gen- eralization of the annihilating ?lter method, a tool widely used in array signal processing and ?nite-rate-of-innovation (FRI) sam- pling. The proposed algorithm can reconstruct spatial samples. For large, this sampling require- ment improves over previously known FRI sampling schemes on the sphere by a factor of four. We showcase the versatility of the proposed algorithm by applying it to three problems: 1) sampling diffusion processes induced by localized sources on the sphere, 2) shot noise removal, and 3) sound source localization (SSL) by a spherical microphone array. In particular, we show how SSL can be reformulated as a spherical sparse sampling problem.
关键词： sparse sampling,spherical harmonics,sphere,Annihilation ?lter,?nite rate of innovavtion,diffusion sampling,shot noise removal,sound source localization
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - An Assessment of Perovskite Solar Cells for Low-Intensity-Low-Temperature (LILT) Space Missions
摘要： We propose a sampling scheme that can perfectly reconstruct a collection of spikes on the sphere from samples of their lowpass-filtered observations. Central to our algorithm is a generalization of the annihilating filter method, a tool widely used in array signal processing and finite-rate-of-innovation (FRI) sampling. The proposed algorithm can reconstruct spatial samples. For large , this sampling requirement improves over previously known FRI sampling schemes on the sphere by a factor of four. We showcase the versatility of the proposed algorithm by applying it to three problems: 1) sampling diffusion processes induced by localized sources on the sphere, 2) shot noise removal, and 3) sound source localization (SSL) by a spherical microphone array. In particular, we show how SSL can be reformulated as a spherical sparse sampling problem.
关键词： sparse sampling,spherical harmonics,finite rate of innovation,sphere,Annihilation filter,diffusion sampling,shot noise removal,sound source localization
更新于2025-09-19 17:13:59
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[IEEE 2019 International Conference on ENERGY and ENVIRONMENT (CIEM) - Timisoara, Romania (2019.10.17-2019.10.18)] 2019 International Conference on ENERGY and ENVIRONMENT (CIEM) - Interharmonic and Harmonic Steady-State Computation of a Grid-Tied Photovoltaic System
摘要： We propose a sampling scheme that can perfectly reconstruct a collection of spikes on the sphere from samples of their lowpass-filtered observations. Central to our algorithm is a generalization of the annihilating filter method, a tool widely used in array signal processing and finite-rate-of-innovation (FRI) sampling. The proposed algorithm can reconstruct spatial samples. For large, this sampling requirement improves over previously known FRI sampling schemes on the sphere by a factor of four. We showcase the versatility of the proposed algorithm by applying it to three problems: 1) sampling diffusion processes induced by localized sources on the sphere, 2) shot noise removal, and 3) sound source localization (SSL) by a spherical microphone array. In particular, we show how SSL can be reformulated as a spherical sparse sampling problem.
关键词： sparse sampling,spherical harmonics,finite rate of innovation,sphere,Annihilation filter,diffusion sampling,shot noise removal,sound source localization
更新于2025-09-19 17:13:59
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[IEEE 2018 IEEE 15th International Symposium on Biomedical Imaging (ISBI 2018) - Washington, DC (2018.4.4-2018.4.7)] 2018 IEEE 15th International Symposium on Biomedical Imaging (ISBI 2018) - An analytical fiber ODF reconstruction in 3D polarized light imaging
摘要： Three dimensional polarized light imaging (3D-PLI) utilizes the birefringence in postmortem tissue to map its spatial fiber structure at a submillimeter resolution. We propose an analytical method to compute the fiber orientation distribution function (ODF) from high-resolution vector data provided by 3D-PLI. This strategy enables the bridging of high resolution 3D-PLI to diffusion magnetic resonance imaging with relatively low spatial resolution. First, the fiber ODF is modeled as a sum of K orientations on the unit sphere and expanded with a high order spherical harmonics series. Then, the coefficients of the spherical harmonics are derived directly with the spherical Fourier transform. We quantitatively validate the accuracy of the reconstruction against synthetic data and show that we can recover complex fiber configurations in the human heart at different scales.
关键词： spherical harmonics,3D-PLI,spherical Fourier transform,fiber orientation distribution function ODF,polarized light imaging
更新于2025-09-10 09:29:36
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[IEEE 2017 51st Asilomar Conference on Signals, Systems, and Computers - Pacific Grove, CA, USA (2017.10.29-2017.11.1)] 2017 51st Asilomar Conference on Signals, Systems, and Computers - Frequency invariant beamforming for arbitrary planar arrays
摘要： In this paper, we present the adaptation to the least-square solution for frequency invariant beamforming to arbitrary planar arrays. This formulation is easily steerable thanks to the decoupling of spatial and spectral constraints. This is achieved with a basis of spherical harmonics polynomials, which parametrize the array response in a term dependent on frequency and a term dependent on the array geometry. Furthermore, the parametrization of the array response Bessel functions decouples the frequency term, which becomes independent of the geometry of the planar array, and allows steering in azimuth and elevation independently. The planar array response is approximated using virtual sensor modeling, which transform any two dimensional planar array in a virtual linear sensors, where azimuth and elevation are separable and can be steered independently.
关键词： frequency invariant beamforming,virtual sensor modeling,planar arrays,spherical harmonics
更新于2025-09-09 09:28:46
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Spherical Harmonic-Based Spectral Projection Model for Holographic SAR Imaging
摘要： A spectral projection model which is based on spherical harmonics is developed for three-dimensional holographic SAR imaging. The addition theorem for spherical harmonics is used for describing the SAR measurement process as a projection of a source spectral vector onto an observation spectral vector. The source vector for a particular scatterer is determined by the spherical coordinates of that scatterer. The dimension of the source vector is determined by the largest dimension of the SAR viewing area. The observation vectors are similarly defined in terms of the spherical coordinates of each measurement point along the SAR flight path. By separating the source and observation terms in the addition theorem, the contribution from each scatterer to each specific SAR measurement is described as the projection of the source spectral vector onto the observation spectral vector. Simulations are used to investigate the spectral properties of a variety of source distributions and SAR flight paths. Sample holographic images are simulated using this spectral projection model.
关键词： addition theorem,Holographic SAR,spectral projection model,spherical harmonics
更新于2025-09-04 15:30:14