Browsing by Author "Way, Der-Lor"

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3D street art illusions: embedding chalk stylized rendering of 3D objects into a pavement photo
(2015-11-01)
Way, Der-Lor
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Hsieh, Cheng-Han
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多媒體工程研究所
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Institute of Multimedia Engineering
Three dimensional street art illusions have become more popular in recent years. Many of them are drawn on pavement such as streets, sidewalks, and town squares. It is often known as 3D chalk art, where a 2D artwork is drawn on the street, giving the viewer a 3D optical illusion from a certain perspective. This paper supplies chalk stylized renderings for 3D models and synthesizes 3D objects into a realistic photograph. Users can input one photo for the 3D model. First, a camera position is achieved by using a camera calibration algorithm. Second, a chalk stylized rendering was applied to create an artistic image of the 3D models using the same camera position. Then, the non-photorealistic rendering image is composited into a source photograph using a modified Poisson approach. All of the enhanced pavement texture details are also blended into the object\'s image. The major contribution of this paper is providing a user to create any interesting and attractive 3D illusionary art without physically drawing pictures on the pavement. Finally, the proposed method is demonstrated using various experimental 3D street art illusion images. Copyright (C) 2014 John Wiley & Sons, Ltd.
3D street art illusions: embedding chalk stylized rendering of 3D objects into a pavement photo
(2015-11-12)
Way, Der-Lor
;
Hsieh, Cheng-Han
;
多媒體工程研究所
;
Institute of Multimedia Engineering
Three dimensional street art illusions have become more popular in recent years. Many of them are drawn on pavement such as streets, sidewalks, and town squares. It is often known as 3D chalk art, where a 2D artwork is drawn on the street, giving the viewer a 3D optical illusion from a certain perspective. This paper supplies chalk stylized renderings for 3D models and synthesizes 3D objects into a realistic photograph. Users can input one photo for the 3D model. First, a camera position is achieved by using a camera calibration algorithm. Second, a chalk stylized rendering was applied to create an artistic image of the 3D models using the same camera position. Then, the non-photorealistic rendering image is composited into a source photograph using a modified Poisson approach. All of the enhanced pavement texture details are also blended into the object\'s image. The major contribution of this paper is providing a user to create any interesting and attractive 3D illusionary art without physically drawing pictures on the pavement. Finally, the proposed method is demonstrated using various experimental 3D street art illusion images. Copyright (C) 2014 John Wiley & Sons, Ltd.
A cartoon-style rendering for physical dynamic hair animation
(2015-03-01)
Way, Der-Lor
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Chang, Yu-Sheng
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多媒體工程研究所
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Institute of Multimedia Engineering
Hair rendering is one of the major research topics in computer graphics. A lot of papers on hair modeling have focused on photo-realistic rendering. This paper proposes a stylized cartoon hair rendering flow diagram including animated hair strand creation, stroke path generation, brush stroke line simulation, and expressive hair rendering. A reordering mechanism addresses depth and stroke line rendering for a suitable performance and temporal coherence. The proposed method creates a delicate expression similar to an artist\'s drawing. To validate real-time performance, all stroke effects are rendered with different shaders on a graphics processing unit. The method is flexible enough to allow users to select shader effects and control the parameters of each activated shader to create esthetically pleasing results. Finally, the proposed method produces excellent experimental results. These results are compared to the results of previous studies.
A directed acyclic graph for pop-up card design
(2015-06-01)
Way, Der-Lor
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Hu, Yong-Ning
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Tsai, Yi-Shan
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多媒體工程研究所
;
Institute of Multimedia Engineering
Pop-up cards are an interesting form of paper art with intriguing geometrical properties. Normally, there are two types of pop-up cards. Origami architecture is a 90-degree card and a v-fold pop up is a 180-degree card. Recently, some approaches have been proposed to aid in the design of a pop-up card. Most of the works on pop-up crafting have used a software tool to design pop-up cards. However, a design tool for a 90-degree card cannot be adopted for the design of a 180-degree card. For the same reason, a method for producing a 180-degree card also cannot be applied to a 90-degree card. This paper proposes a directed acyclic graph (DAG) for designing both types of pop-up cards. These two types of pop-up cards could be created with DAG data structure. The DAG algorithm ensures that the pop-up card is foldable, stable, and intersection-free when opened and closed. The proposed method is demonstrated with various paper pop-up cards, and experimental examples are presented.
Adaptive sampling approach for volumetric shadows in dynamic scenes
(2013-11-01)
Lin, Hsiang-Yu
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Chang, Chin-Chen
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Tsai, Yu-Ting
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Way, Der-Lor
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Shih, Zen-Chung
Ray marching is an important technique to generate volumetric lighting effects. However, it is very expensive for each pixel on the screen, especially in dynamic scenes. The authors propose an adaptive approach to reduce samples for volumetric shadows in the time domain. In dynamic scenes, shadow volumes of moving objects are created and are rasterised to decide pixels that cannot be reused. The authors use a stencil buffer to maintain the information of screen pixels by recomputing or just using the previous information. Experimental results show that the proposed approach is simple to implement. Moreover, compared to the previous method, the proposed approach achieves a specific speedup and maintains similar visual quality.
An Efficient Structure-Aware Bilateral Texture Filtering for Image Smoothing
(2016-10-01)
Lin, Ting-Hao
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Way, Der-Lor
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Shih, Zen-Chung
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Tai, Wen-Kai
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Chang, Chin-Chen
Photos contain well-structured and plentiful visual information. Edges are active and expressive stimuli for human visual perception. However, it is hard to separate structure from details because edge strength and object scale are entirely different concepts. This paper proposes a structure-aware bilateral texture algorithm to remove texture patterns and preserve structures. Our proposed method is simple and fast, as well as effective in removing textures. Instead of patch shift, smaller patches represent pixels located at structure edges, and original patches represent the texture regions. Specifically, this paper also improves joint bilateral filter to preserve small structures. Moreover, a windowed inherent variation is adapted to distinguish textures and structures for detecting structure edges. Finally, the proposed method produces excellent experimental results. These results are compared to some results of previous studies. Besides, structure-preserving filtering is a critical operation in many image processing applications. Our proposed filter is also demonstrated in many attractive applications, such as seam carving, detail enhancement, artistic rendering, etc.
An Efficient Structure-Aware Bilateral Texture Filtering for Image Smoothing
(2016-10)
Lin, Ting-Hao
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Way, Der-Lor
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Shih, Zen-Chung
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Tai, Wen-Kai
;
Chang, Chin-Chen
Photos contain well-structured and plentiful visual information. Edges are active and expressive stimuli for human visual perception. However, it is hard to separate structure from details because edge strength and object scale are entirely different concepts. This paper proposes a structure-aware bilateral texture algorithm to remove texture patterns and preserve structures. Our proposed method is simple and fast, as well as effective in removing textures. Instead of patch shift, smaller patches represent pixels located at structure edges, and original patches represent the texture regions. Specifically, this paper also improves joint bilateral filter to preserve small structures. Moreover, a windowed inherent variation is adapted to distinguish textures and structures for detecting structure edges. Finally, the proposed method produces excellent experimental results. These results are compared to some results of previous studies. Besides, structure-preserving filtering is a critical operation in many image processing applications. Our proposed filter is also demonstrated in many attractive applications, such as seam carving, detail enhancement, artistic rendering, etc.
An Improved Style Transfer Approach for Videos
(2018-01-01)
Chang, Rong-Jie
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Chang, Chin-Chen
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Way, Der-Lor
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Shih, Zen -Chung
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資訊工程學系
In this paper, we present an improved approach to transfer style for videos based on semantic segmentation. We segment foreground objects and background, and then apply different styles respectively. A fully convolutional neural network is used to perform semantic segmentation. We increase the reliability of the segmentation, and use the information of segmentation and the relationship between foreground objects and background to improve segmentation iteratively. We also use segmentation to improve optical flow, and apply different motion estimation methods between foreground objects and background. This improves the motion boundaries of optical flow, and solves the problems of incorrect and discontinuous segmentation caused by occlusion and shape deformation.
Clip Space Sample Culling for Motion Blur and Defocus Blur
(2015-05-01)
Wu, Yi-Jeng
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Way, Der-Lor
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Tsai, Yu-Ting
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Shih, Zen-Chung
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多媒體工程研究所
Motion blur and defocus blur are two common visual effects for rendering realistic camera images. This paper presents a novel clip space culling for stochastic rasterization to render motion and defocus blur effects. Our proposed algorithm reduces the sample coverage using the clip space information in camera lens domain (UV) and time domain (T). First, samples outside the camera lens were culled in stage I using the linear relationship between camera lens and vertex position. Second, samples outside the time bounds were culled in stage II using the triangle similarity in clip space to find the intersection time. Each pixel was computed within two linear bounds only once. Our method achieves good sample test efficiency with low computation cost for real-time stochastic rasterization. Finally, the proposed method is demonstrated by means of various experiments, and a comparison is made with previous works. Our algorithm was able to handle these two blur effects simultaneously and performed better than others did.
Computer-generated Chinese color ink paintings
(2006-10-01)
Way, Der-Lor
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Lin, Wei-Jin
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Shih, Zen-Chung
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資訊工程學系
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Department of Computer Science
Chinese color ink painting is a traditional art form, a non-photorealistic rendering, that is over three thousand years old. Simulating the behavior of Chinese ink is challenging. Various artistic effects of color ink diffusion are analyzed, and a scheme presents how they can be simulated automatically for their computer-generated simulation. The proposed method simulates various tonal expressions on different papers. by employing a Kubelka-Munk model to simulate optical effects. Elucidation of the effect of mixing simulated strokes with different brushes is a significant contribution of the proposed method. Finally, results of this study demonstrate the effectiveness of an interactive painting system. Also, results are compared with genuine ink paintings.
Generation of Stereo Images Based on a View Synthesis Network
(2020-05-01)
Lo, Yuan-Mau
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Chang, Chin-Chen
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Way, Der-Lor
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Shih, Zen-Chung
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多媒體工程研究所
The conventional warping method only considers translations of pixels to generate stereo images. In this paper, we propose a model that can generate stereo images from a single image, considering both translation as well as rotation of objects in the image. We modified the appearance flow network to make it more general and suitable for our model. We also used a reference image to improve the inpainting method. The quality of images resulting from our model is better than that of images generated using conventional warping. Our model also better retained the structure of objects in the input image. In addition, our model does not limit the size of the input image. Most importantly, because our model considers the rotation of objects, the resulting images appear more stereoscopic when viewed with a device.
Inner engraving for the creation of a balanced LEGO sculpture
(2016-05)
Hong, Jhen-Yao
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Way, Der-Lor
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Shih, Zen-Chung
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Tai, Wen-Kai
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Chang, Chin-Chen
LEGO is a globally popular toy composed of colorful interlocking plastic bricks that can be assembled in many ways; however, this special feature makes designing a LEGO sculpture particularly challenging. Building a stable sculpture is not easy for a beginner; even an experienced user requires a good deal of time to build one. This paper provides a novel approach to creating a balanced LEGO sculpture for a 3D model in any pose, using centroid adjustment and inner engraving. First, the input 3D model is transformed into a voxel data structure. Next, the model\'s centroid is adjusted to an appropriate position using inner engraving to ensure that the model stands stably. A model can stand stably without any struts when the center of mass is moved to the ideal position. Third, voxels are merged into layer-by-layer brick layout assembly instructions. Finally, users will be able to build a LEGO sculpture by following these instructions. The proposed method is demonstrated with a number of LEGO sculptures and the results of the physical experiments are presented.
Origami Pop-up Card Generation from 3D Models Using a Directed Acyclic Graph
(2013-11-01)
Way, Der-Lor
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Tsai, Yi-Shan
;
Shih, Zen-Chung
;
資訊工程學系
;
Department of Computer Science
Origami is a paper art used to create three-dimensional (3D) objects by cutting and folding a single sheet of paper. Origami is labor-intensive and requires a high skill level to generate two-dimensional (2D) objects that pop-up into realistic 3D objects. However, this special feature makes designing an origami architecture procedure challenging. This paper provides a novel algorithm to create an origami paper card from a 3D model with a user-specified folding line. The algorithm segments the 2D shape from a 3D model and creates layers of the pop-up paper card using a directed acyclic graph. After applying layers to the layout, the algorithm creates connections between layers, and then outputs the origami layout. Based on a directed acyclic graph, the algorithm computes a class of paper architectures containing two sets of layers and connections that approximate the input geometry while guaranteeing that a pop up card is physically realizable. The proposed method is demonstrated with a number of paper pop-ups, and physical experimental results are presented.