After a review of the planar garment effect production of pattern fabric and a brief introduction of the concept of texture mapping, the theory of 2D texture mapping onto 3D surface is stated. And the calculation proc...After a review of the planar garment effect production of pattern fabric and a brief introduction of the concept of texture mapping, the theory of 2D texture mapping onto 3D surface is stated. And the calculation procedures of texture mapping, such as texture image preprocess,mannequin and garment surface modeling, mapping relationship definition, shading/texturing model creation, and graphic transformation,are exploited to produce a real 3D garment rendring effect.Finally, the conclusion is given about the realization envlronment and affecting factors of the final images.展开更多
Three-dimensional(3D)fetal ultrasound has been widely used in prenatal examinations.Realistic and real-time volumetric ultrasound volume rendering can enhance the effectiveness of diagnoses and assist obstetricians an...Three-dimensional(3D)fetal ultrasound has been widely used in prenatal examinations.Realistic and real-time volumetric ultrasound volume rendering can enhance the effectiveness of diagnoses and assist obstetricians and pregnant mothers in communicating.However,this remains a challenging task because(1)there is a large amount of speckle noise in ultrasound images and(2)ultrasound images usually have low contrasts,making it difficult to distinguish different tissues and organs.However,traditional local-illumination-based methods do not achieve satisfactory results.This real-time requirement makes the task increasingly challenging.This study presents a novel real-time volume-rendering method equipped with a global illumination model for 3D fetal ultrasound visualization.This method can render direct illumination and indirect illumination separately by calculating single scattering and multiple scattering radiances,respectively.The indirect illumination effect was simulated using volumetric photon mapping.Calculating each photon’s brightness is proposed using a novel screen-space destiny estimation to avoid complicated storage structures and accelerate computation.This study proposes a high dynamic range approach to address the issue of fetal skin with a dynamic range exceeding that of the display device.Experiments show that our technology,compared to conventional methodologies,can generate realistic rendering results with far more depth information.展开更多
Realism rendering methods of outdoor augmented reality(AR)is an interesting topic.Realism items in outdoor AR need advanced impacts like shadows,sunshine,and relations between unreal items.A few realistic rendering ap...Realism rendering methods of outdoor augmented reality(AR)is an interesting topic.Realism items in outdoor AR need advanced impacts like shadows,sunshine,and relations between unreal items.A few realistic rendering approaches were built to overcome this issue.Several of these approaches are not dealt with real-time rendering.However,the issue remains an active research topic,especially in outdoor rendering.This paper introduces a new approach to accomplish reality real-time outdoor rendering by considering the relation between items in AR regarding shadows in any place during daylight.The proposed method includes three principal stages that cover various outdoor AR rendering challenges.First,real shadow recognition was generated considering the sun’s location and the intensity of the shadow.The second step involves real shadow protection.Finally,we introduced a shadow production algorithm technique and shades through its impacts on unreal items in the AR.The selected approach’s target is providing a fast shadow recognition technique without affecting the system’s accuracy.It achieved an average accuracy of 95.1%and an area under the curve(AUC)of 92.5%.The outputs demonstrated that the proposed approach had enhanced the reality of outside AR rendering.The results of the proposed method outperformed other state-of-the-art rendering shadow techniques’outcomes.展开更多
In order to perform a high-quality interactive rendering of large medical data sets on a single off-the-shelf PC, a LOD selection algorithm for multi-resolution volume rendering using 3D texture mapping is presented, ...In order to perform a high-quality interactive rendering of large medical data sets on a single off-the-shelf PC, a LOD selection algorithm for multi-resolution volume rendering using 3D texture mapping is presented, which uses an adaptive scheme that renders the volume in a region-of-interest at a high resolution and the volume away from this region at lower resolutions. The algorithm is based on several important criteria, and rendering is done adaptively by selecting high-resolution cells close to a center of attention and low-resolution cells away from this area. In addition, our hierarchical level-of-detail representation guarantees consistent interpolation between different resolution levels. Experiments have been applied to a number of large medical data and have produced high quality images at interactive frame rates using standard PC hardware.展开更多
Owing to its generality and efficiency, Cascaded Shadow Maps （CSMs） has an important role in real-time shadow rendering in large scale and complex virtual environments. However, CSMs suffers from redundant rendering...Owing to its generality and efficiency, Cascaded Shadow Maps （CSMs） has an important role in real-time shadow rendering in large scale and complex virtual environments. However, CSMs suffers from redundant rendering problem -- objects are rendered undesirably to different shadow map textures when view direction and light direction are not perpendicular. In this paper, we present a light space cascaded shadow maps algorithm. The algorithm splits a scene into non-intersecting layers in light space, and generates one shadow map for each layer through irregular frustum clipping and scene organization, ensuring that any shadow sample point never appears in multiple shadow maps. A succinct shadow determination method is given to choose the optimal shadow map when rendering scenes. We also combine the algorithm with stable cascaded shadow maps and soft shadow algorithm to avoid shadow flicking and produce soft shadows. The results show that the algorithm effectively improves the efficiency and shadow quality of CSMs by avoiding redundant rendering, and can produce high-quality shadow rendering in large scale dynamic environments with real-time performance.展开更多
文摘After a review of the planar garment effect production of pattern fabric and a brief introduction of the concept of texture mapping, the theory of 2D texture mapping onto 3D surface is stated. And the calculation procedures of texture mapping, such as texture image preprocess,mannequin and garment surface modeling, mapping relationship definition, shading/texturing model creation, and graphic transformation,are exploited to produce a real 3D garment rendring effect.Finally, the conclusion is given about the realization envlronment and affecting factors of the final images.
基金supported by a grant from General Research Fund of Hong Kong Research Grants Council,No.15218521a grant under the scheme of Collaborative Research with World-leading Research Groups in the Hong Kong Polytechnic University,No.G-SACF。
文摘Three-dimensional(3D)fetal ultrasound has been widely used in prenatal examinations.Realistic and real-time volumetric ultrasound volume rendering can enhance the effectiveness of diagnoses and assist obstetricians and pregnant mothers in communicating.However,this remains a challenging task because(1)there is a large amount of speckle noise in ultrasound images and(2)ultrasound images usually have low contrasts,making it difficult to distinguish different tissues and organs.However,traditional local-illumination-based methods do not achieve satisfactory results.This real-time requirement makes the task increasingly challenging.This study presents a novel real-time volume-rendering method equipped with a global illumination model for 3D fetal ultrasound visualization.This method can render direct illumination and indirect illumination separately by calculating single scattering and multiple scattering radiances,respectively.The indirect illumination effect was simulated using volumetric photon mapping.Calculating each photon’s brightness is proposed using a novel screen-space destiny estimation to avoid complicated storage structures and accelerate computation.This study proposes a high dynamic range approach to address the issue of fetal skin with a dynamic range exceeding that of the display device.Experiments show that our technology,compared to conventional methodologies,can generate realistic rendering results with far more depth information.
文摘Realism rendering methods of outdoor augmented reality(AR)is an interesting topic.Realism items in outdoor AR need advanced impacts like shadows,sunshine,and relations between unreal items.A few realistic rendering approaches were built to overcome this issue.Several of these approaches are not dealt with real-time rendering.However,the issue remains an active research topic,especially in outdoor rendering.This paper introduces a new approach to accomplish reality real-time outdoor rendering by considering the relation between items in AR regarding shadows in any place during daylight.The proposed method includes three principal stages that cover various outdoor AR rendering challenges.First,real shadow recognition was generated considering the sun’s location and the intensity of the shadow.The second step involves real shadow protection.Finally,we introduced a shadow production algorithm technique and shades through its impacts on unreal items in the AR.The selected approach’s target is providing a fast shadow recognition technique without affecting the system’s accuracy.It achieved an average accuracy of 95.1%and an area under the curve(AUC)of 92.5%.The outputs demonstrated that the proposed approach had enhanced the reality of outside AR rendering.The results of the proposed method outperformed other state-of-the-art rendering shadow techniques’outcomes.
基金the Advanced Project Foundation between China and France(PRA SI03-02).
文摘In order to perform a high-quality interactive rendering of large medical data sets on a single off-the-shelf PC, a LOD selection algorithm for multi-resolution volume rendering using 3D texture mapping is presented, which uses an adaptive scheme that renders the volume in a region-of-interest at a high resolution and the volume away from this region at lower resolutions. The algorithm is based on several important criteria, and rendering is done adaptively by selecting high-resolution cells close to a center of attention and low-resolution cells away from this area. In addition, our hierarchical level-of-detail representation guarantees consistent interpolation between different resolution levels. Experiments have been applied to a number of large medical data and have produced high quality images at interactive frame rates using standard PC hardware.
基金supported by the National Natural Science Foundation of China under Grant No.60873159Program for New Century Excellent Talents in University under Grant No.NCET-07-0039+1 种基金the National High-Tech Research & Development 863 Program of China under Grant No.2009AA012103the Beijing Municipal Natural Science Foundation under Grant No.4102030
文摘Owing to its generality and efficiency, Cascaded Shadow Maps （CSMs） has an important role in real-time shadow rendering in large scale and complex virtual environments. However, CSMs suffers from redundant rendering problem -- objects are rendered undesirably to different shadow map textures when view direction and light direction are not perpendicular. In this paper, we present a light space cascaded shadow maps algorithm. The algorithm splits a scene into non-intersecting layers in light space, and generates one shadow map for each layer through irregular frustum clipping and scene organization, ensuring that any shadow sample point never appears in multiple shadow maps. A succinct shadow determination method is given to choose the optimal shadow map when rendering scenes. We also combine the algorithm with stable cascaded shadow maps and soft shadow algorithm to avoid shadow flicking and produce soft shadows. The results show that the algorithm effectively improves the efficiency and shadow quality of CSMs by avoiding redundant rendering, and can produce high-quality shadow rendering in large scale dynamic environments with real-time performance.
