ABSTRACT Through the advancement of electronics technologies, human motion analysis applications ... more ABSTRACT Through the advancement of electronics technologies, human motion analysis applications span many domains. Existing commercially available magnetic, mechanical and optical systems for motion capture and analyses are far from being able to operate in ...
In this paper, we propose a robust moment invariant which has a higher discriminant factor based ... more In this paper, we propose a robust moment invariant which has a higher discriminant factor based on Fisher linear discriminant analysis that can deal with noise degradation, deformation of vector distortion, translation, rotation and scale invariant. The proposed system for the symbol recognition consists of 3 steps: 1) degradation model preprocessing step, 2) a different normalization for the second moment
We present a real-time GPU caustics rendering technique for dynamic scenes under environment illu... more We present a real-time GPU caustics rendering technique for dynamic scenes under environment illumination taking into account light occlusion. The dynamic scenes consist of caustic objects (reflective and/or refractive objects which produce caustics) and receiver objects (non-reflective and nonrefractive), that can be translated and rotated. As the light source, we consider environment illumination (distant lights from all directions) which we approximate as a set of important directional lights. Our rendering technique is able to generate approximate caustics cast on receiver objects as well as volumetric caustics. As the preprocessing, we precompute the caustic patterns of caustic objects for several directional lights and store them in caustic images. During the rendering, we interpolate the precomputed caustic patterns based on the important directional lights which approximate the given environment illumination. The important directional lights are obtained by using our proposed environment cube map segmentation technique. Our proposed technique is able to generate real-time caustics which are visually similar to the caustic generated by using a commercial renderer mental ray.
In the real world, the index of refraction of a refractive object (caustic object) varies across ... more In the real world, the index of refraction of a refractive object (caustic object) varies across the wavelengths. Therefore, in physically-based caustic rendering, we need to take into account spectral information. However, this may lead to prohibitive running time. In response, we propose a two-step acceleration scheme for spectral caustic rendering. Our acceleration scheme takes into account information across visible wavelengths of the scene, that is, the index of refrac- tion (caustic object), light power (light), and material reflectance (surface). To process visible wavelengths effectively, firstly we cluster the wavelengths which have similar first-refraction (air to caustic object) directions. In this way, all the wavelengths in a cluster can be represented by one light ray during rendering. Secondly, by considering the surrounding objects (their material reflectance and their visible surface area from the caustic objects) and light power, we compute the refinement amount of each wavelength cluster. Our accelerated algorithm can produce photorealistic rendering results close to their reference images (which are generated by rendering every 1 nm of visible wavelengths) with a significant acceleration magnitude. Computational experiment results and comparative analyses are reported in the paper.
We present a real-time GPU caustics rendering technique in dynamic scenes under multiple directio... more We present a real-time GPU caustics rendering technique in dynamic scenes under multiple directional lights taking into account light occlusion. Our technique renders caustics cast on receiver objects as well as volumetric caustics. We precompute caustic patterns of caustic objects for several directional lights and store them in caustic images. During the rendering, we interpolate the precomputed caustic patterns based on a given light direction. One of the applications of our technique is to render approximate caustics under environment illumination. To achieve this, we propose an environment cube map segmentation technique which divides cube maps into several light regions with each region is represented using one directional light.
Inverse caustic problem, that is computing the geometry of a reflector and/or refractor based on ... more Inverse caustic problem, that is computing the geometry of a reflector and/or refractor based on a given caustic pattern, is currently not widely studied. In this paper, we propose a technique to solve the inverse caustic problem in which we compute the geometry of a semi-transparent homogeneous refractive object (caustic object) given a directional light source and a set of caustic patterns (each pattern is considered to be formed at a specified distance from the caustic object). We validate the results by using mental ray (software rendering). The novelty of our research is that we consider a set of caustic patterns whereas existing techniques only consider one caustic pattern. We employ a stochastic approach to simulate the refracted light beam paths that can approximately reconstruct the input caustic patterns. Working backward, from the computed refracted light beam paths we compute the geometry of the caustic object that can produce such light beam paths. Due to having multiple caustic patterns as the inputs, it is a challenge to reconstruct the input caustic patterns because of the differences in their shapes and intensities. We solve this problem by using a two-step optimization algorithm in which we adjust the position and size of the caustic regions in the first step and we adjust the caustic shapes in the second step. Our technique is able to construct a caustic object for a various types of input caustic patterns.
ABSTRACT This issue, we travel to Singapore for an update of this country's computer grap... more ABSTRACT This issue, we travel to Singapore for an update of this country's computer graphics activities.
In order to achieve precise, accurate and reliable tracking of human movement, a 3D human model t... more In order to achieve precise, accurate and reliable tracking of human movement, a 3D human model that is very similar to the subject is essential. In this paper, we present a new system to (1) precisely construct the surface shape of the whole human body, and (2) estimate the underlying skeleton. In this work we make use of a set of images of the subject in collaboration with a generic anthropometrical 3D model made up of regular surfaces and skeletons to adapt to the specific subject. We developed a three-stage technique that uses the human shape feature points and limb outlines that work together with the generic 3D model to yield our final customized 3D model. The first stage is an iterative camera pose calibration and 3D characteristic point reconstruction-deformation algorithm that gives us an initial customized 3D model. The second stage refines the initial customized 3D model by deformation via the silhouette limbs information, thus obtaining the surface skin model. In the final stage, we make use of the results of skin deformation to estimate the underlying skeleton. From our final results, we demonstrate that our system is able to construct quality human model, where the skeleton is constructed and positioned automatically.
NPAR’16 Proceedings of the Workshop on Non-Photorealistic Animation and Rendering
This paper presents a system to render 3D animated geometry as watercolor painted animation with ... more This paper presents a system to render 3D animated geometry as watercolor painted animation with art-directed control. Our approach focuses on letting the end user paint the influence of the modeled watercolor effects in the 3D scene to simulate the characteristic appearance of traditional watercolor. For this purpose, it performs an object-space simulation and makes use of the user-painted influences to control and enhance image-space watercolor effects. In contrast to previous approaches, we introduce specialized watercolor shaders that are adjusted and deformed according to the desired painted effects. We further present novel algorithms that simulate hand tremors, pigment turbulence, color bleeding, edge darkening, paper distortion and granulation. All of these represent essential characteristic effects of traditional watercolor. The system performs in real-time, scales well with scene complexity and is fully implemented in Autodesk Maya.
4th IEEE International Conference on Digital Ecosystems and Technologies, 2010
In today's interactive digital world, online social networking can play a vital role in cultivati... more In today's interactive digital world, online social networking can play a vital role in cultivating an 'unspoken' cyber culture that may shape users' opinions, sense of belonging, and values amongst the youths. As youths immerse themselves in using sophisticated interactive media, they are not only articulating ideas and thoughts; they are also sharing their beliefs and hence influencing others to adopt a new cyber culture. Indeed, participatory online culture describes a community which offers support and mentorship to members as they feel they are connected to others and that their contributions matter. This paper proposes an online collaborative framework to provide youths a fun and innovative platform to communicate, collaborate and create via simple animation and story-telling techniques. In providing youths a new avenue for expressing their artistic talents in an informal environment, we hope to understand the context in which they use social media to form a popular culture.
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Papers by Hock Soon Seah
tion (caustic object), light power (light), and material reflectance (surface). To process visible wavelengths effectively, firstly we cluster the wavelengths which have similar first-refraction (air to caustic object) directions. In this way, all the wavelengths in a cluster can be represented by one light ray during rendering. Secondly, by considering the surrounding objects (their material reflectance and their visible surface area from the caustic objects) and light power, we compute the refinement
amount of each wavelength cluster. Our accelerated algorithm can produce photorealistic rendering results close to their reference images (which are generated by rendering every 1 nm of visible wavelengths) with a significant acceleration magnitude. Computational experiment results and comparative analyses are reported in the paper.