Browsing by Author "Huang, Tsung-Shian"

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An Artist Friendly Material Design System
(2017-03-01)
Huang, Tsung-Shian
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Liao, Jen-Hao
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Lin, Wen-Chieh
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Chuang, Jung-Hong
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資訊工程學系
Material design is an important task in game and animation industry. It often requires artist's great efforts to create an elaborate material. Although several successful material editing systems already exist, it is still hard for artists to design a material on their own since these systems usually have neither an intuitive and sufficiently sophisticated material representation nor an artist-friendly editing interface. In this paper, we propose a simple material creation flow and develop a material design system based on an intuitive material representation. With the system, an artist can bring their creativity into play on designing materials that are realistic or imaginary.
Exemplar-based freckle retouching and skin tone adjustment
(2019-02-01)
Lin, Tsung-Ying
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Tsai, Yu-Ting
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Huang, Tsung-Shian
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Lin, Wen-Chieh
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Chuang, Jung-Hong
This paper presents a novel system for freckle retouching and skin tone adjustment based on a set of exemplar image pairs obtained before and after cosmetic laser therapy. Our key observation is that cosmetic laser therapy relies on decomposing and adjusting melanin and hemoglobin to change skin appearance, and the reflectance properties of the two pigments can greatly influence human skin color. We thus retouch freckles and adjust skin tone in a query image by changing the densities of melanin and hemoglobin to match the variation of those in the exemplar image pairs. Based on the proposed system, we can easily and intuitively generate an output image that looks similar to the results of cosmetic laser therapy. Our system also can detect more skin flaws and define their regions more accurately than previous retouching methods. (C) 2018 Elsevier Ltd. All rights reserved.
Interactive Lighting Design with Hierarchical Light Representation
(2013-06-01)
Lin, Wen-Chieh
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Huang, Tsung-Shian
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Ho, Tan-Chi
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Chen, Yueh-Tse
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Chuang, Jung-Hong
Lighting design plays a crucial role in indoor lighting design, computer cinematograph and many other applications. Computer-assisted lighting design aims to find a lighting configuration that best approximates the illumination effect specified by designers. In this paper, we present an automatic approach for lighting design, in which discrete and continuous optimization of the lighting configuration, including the number, intensity, and position of lights, are achieved. Our lighting design algorithm consists of two major steps. The first step estimates an initial lighting configuration by light sampling and clustering. The initial light clusters are then recursively merged to form a light hierarchy. The second step optimizes the lighting configuration by alternatively selecting a light cut on the light hierarchy to determine the number of representative lights and optimizing the lighting parameters using the simplex method. To speed up the optimization computation, only illumination at scene vertices that are important to rendering are sampled and taken into account in the optimization. Using the proposed approach, we develop a lighting design system that can compute appropriate lighting configurations to generate the illumination effects iteratively painted and modified by a designer interactively.
Lighting and Foggy Effect Transfer
(2017-09-01)
Huang, Tsung-Shian
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Huang, Fu-Hsi
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Lin, Wen-Chieh
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Chuang, Jung-Hong
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資訊工程學系
Participating media, e.g., fog and smoke, play an important role in computer animation and games. They influence the atmosphere of scenes by inducing some special lighting effects, such as the distant blur, glows, and god rays. To design the lighting effects in a scene with fog or smoke, users usually need to tune many parameters to achieve their goal. In this paper, we propose a method that aims to transfer the desired lighting and homogeneous foggy effects in target images, including glow, god rays, and fog attributes, to a 3D scene by solving an inverse problem. The experimental results show that our approach is effective, intuitive, and user-friendly.
Line Drawing Simplification by Stroke Translation and Combination
(2014)
Chien, Yun
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Lin, Wen-Chieh
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Huang, Tsung-Shian
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Chuang, Jung-Hong
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資訊工程學系
In this paper, we propose a new algorithm for simplifying line drawing sketches. First, we segment the strokes at the points of large curvature if desired. Then, we perform a low-pass filter and use the result to assign a weight to every stroke. The strokes are moved to the position of the higher weight. After that, we find the stroke pairs and combine them to reduce the total number of the strokes, resulting in a cleaner line drawing art. This system also cuts down the disordered and confusing small strokes and combines them to form long strokes.
Physically based cosmetic rendering
(2013-05-01)
Huang, Cheng-Guo
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Huang, Tsung-Shian
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Lin, Wen-Chieh
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Chuang, Jung-Hong
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資訊工程學系
Simulating realistic makeup effects is one of the important research issues in the 3D facial animation and cosmetic industry. Existing approaches based on image processing techniques, such as warping and blending, have been mostly applied to transfer one's makeup to another's. Although these approaches are intuitive and need only makeup images, they have some drawbacks, for example, distorted shapes and fixed viewing and lighting conditions. In this paper, we propose an integrated approach, which combines the KubelkaMunk model and a screen-space skin rendering approach, to simulate 3D makeup effects. The KubelkaMunk model is used to compute total transmittance when light passes through cosmetic layers, whereas the screen-space translucent rendering approach simulates the subsurface scattering effects inside human skin. The parameters of KubelkaMunk model are obtained by measuring the optical properties of different cosmetic materials, such as foundations, blushes, and lipsticks. Our results demonstrate that the proposed approach is able to render realistic cosmetic effects on human facial models, and different cosmetic materials and styles can be flexibly applied and simulated in real time. Copyright (c) 2013 John Wiley & Sons, Ltd.
Real-time translucent rendering using GPU-based texture space importance sampling
(2008-04-01)
Chang, Chih-Wen
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Lin, Wen-Chieh
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Ho, Tan-Chi
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Huang, Tsung-Shian
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Chuang, Jung-Hong
We present a novel approach for real-time rendering of translucent surfaces. The computation of subsurface scattering is performed by first converting the integration over the 3D model surface into an integration over a 2D texture space and then applying importance sampling based on the irradiance stored in the texture. Such a conversion leads to a feasible GPU implementation and makes real-time frame rate possible. Our implementation shows that plausible images can be rendered in real time for complex translucent models with dynamic light and material properties. For objects with more apparent local effect, our approach generally requires more samples that may downgrade the frame rate. To deal with this case, we decompose the integration into two parts, one for local effect and the other for global effect, which are evaluated by the combination of available methods [DS03, MKB* 03a] and our texture space importance sampling, respectively. Such a hybrid scheme is able to steadily render the translucent effect in real time with a fixed amount of samples.
Simulating painted appearance of BTF materials
(2018-03-01)
Chen, Ta-En
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Huang, Tsung-Shian
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Lin, Wen-Chieh
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Chuang, Jung-Hong
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資訊工程學系
Bidirectional texture function (BTF) provides a realistic representation for real-world materials; however, the representation does not allow users to append additional rendering effects to the BTF data in a simple and effective way. In this paper, we present an approach for generating the painted appearance on a material that is represented by a BTF. We first convert a BTF into a physical representation composed of a height-field and a spatially varying bidirectional reflectance distribution function (SVBRDF). This representation allows us to simulate the appearance of paints on the surface of a material by computing the reflectance and the height field of the painted material. During rendering, we combine an existing BTF rendering approach and the modified material data to simulate the painted appearance of the BTF materials. Our experiments show that the proposed approach can simulate the painted appearance of a material while preserving the characteristic appearance of the original BTF. Our approach is mainly suitable for less specular BTF materials that allow depth reconstruction.