VVG05

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https://diglib.eg.org/handle/10.2312/1030

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Modeling Falling and Accumulating Snow
(The Eurographics Association, 2005) Moeslund, T. B.; Madsen, C. B.; Aagaard, M.; Lerche, D.; Mike Chantler
The use of computer graphics to produce special effects is currently being applied with great results in especially the entertainment and game industry. One area where computer graphics is not quite ready to replace all real effects is natural phenomena where a lack of general models exists. In this work we present a general model for falling and accumulating snow. The appearance and movement of falling snow are modeled in 3D based on the physics governing the real processes. The same goes for the accumulated snow where especially a correctly modeled wind field is important for producing realistically looking results. Intuitive weather parameters are used to control both models. The results show that both the appearance and movement of the snow, as well as the accumulated snow are very similar to real snow.
Multi-View Image Coding with Wavelet Lifting Scheme
(The Eurographics Association, 2005) Anantrasirichai, N.; Canagarajah, C. Nishan; Bull, David R.; Mike Chantler
In this paper, we present a novel multi-view image codec based on a wavelet lifting scheme. The proposed algorithm applies the disparity estimation and compensation with the lifting scheme. It is very efficient in terms of compressions performance, memory requirements and fast computation. To get the highest multiview image coding efficiencies, two hybrid predictions are proposed; one for effective compression performance and one for compromising when more exact disparity values are required. Moreover, an adaptive weighing in update step and overlapped block disparity compensation are included to yield significant improvements in rate distortion performance. Experimental results show image quality gains of up to 2 dB and 1 dB against using well established methods such as the block-matching Haar and 5/3 wavelet lifting respectively.
Linear Hashtable Method and Predicted Hexagonal Search Algorithm with Moments Invariant
(The Eurographics Association, 2005) Wu, Yunsong; Megson, Graham; Nie, Zhengang; Liu, Xuan; Mike Chantler
This paper presents a novel Linear Hashtable Method Predicted Hexagonal Search (LHMPHS) method for block base motion compensation on the basis of research from previous algorithm. Hashtable is used in video compression. Motion vectors produced by Linear Hashtable Motion Estimation Algorithm (LHMEA) are used as predictors for HEXBS. Moments invariants are also tested in hashtable to prove the more information moments have, the better it is. Experimental results show that the proposed algorithm can offer the same compression rate as the Full Search and fastest than all investigated algorithms, while the PSNR is high. LHMPHS has significant improvement on HEXBS and shows a direction for improving other fast motion estimation algorithms.
Monte Carlo Noise Reduction Using Bayesian Method in Wavelet domain
(The Eurographics Association, 2005) Xu, Ruifeng; Pattanaik, Sumanta N.; Mike Chantler
A novel post-processing approach for removing Monte Carlo noises in synthetic images is presented in this paper. This paper first presents our findings on the statistical characteristics of the Monte Carlo noise, and then proposes a Bayesian method to remove this noise. The aim of this approach is to efficiently produce high quality synthetic images using Monte Carlo based rendering at low sampling rates.
Natural Image Matting
(The Eurographics Association, 2005) Hillman, Peter M.; Hannah, John M.; Mike Chantler
Matte pulling - generating greyscale images which indicate segmentation of images into elements with subpixel accuracy and where blur causes pixels to be a mixture of elements - has received attention in recent years. Many of the algorithms are too slow or too unpredictable to be of practical use in motion picture Post-production. Assessing the performance of different algorithms is also a complex task. This paper presents an optimisation which can be applied to many algorithms in order to allow them to run at interactive speeds, introduces a new algorithm based on Colour Lines, and presents a technique which can be used as a formal test-bench to measure the performance of matte algorithms.
Image classification using compression distance
(The Eurographics Association, 2005) Lan, Yuxuan; Harvey, Richard; Mike Chantler
The normalised compression distance measures the mutual compressibility of two signals. We show that this distance can be used for classification on real images. Furthermore, the same compressor can also operate on derived features with no further modification. We consider derived features consisting of trees indicating the containment and relative area of connected sets within the image. It had been previously postulated that such trees might be useful features, but they are too complicated for conventional classifiers. The new classifier operating on these trees produces results that are very similar to those obtained on the raw images thus allowing, for the first time, classification using the full trees.
Motion Analysis in Video: Dolls, Dynamic Cues and Modern Art
(The Eurographics Association, 2005) Collomosse, J. P.; Hall, P. M.; Mike Chantler
This paper addresses the problem of synthesising animations from video clips; in particular emphasising the motion of tracked objects. We introduce "dynamic cues" as a class of motion emphasis cue, encompassing traditional animation techniques such as anticipation and exaggeration. We present methods for automatically synthesising such cues within video premised upon the recovery of articulated figures, and the subsequent manipulation of the recovered pose trajectories. Additionally, we apply our motion emphasis framework to emulate artwork in the Futurist style, popularised by Duchamp.
Automatic Non-Photorealistic Rendering through Soft-Shading Removal: A Colour-Vision Approach
(The Eurographics Association, 2005) Olmos, A.; Kingdom, F. A. A.; Mike Chantler
This paper presents a non-photorealistic rendering algorithm that produces "stylised-style" images by removing the soft shading from the image and by giving objects extra definition through black outlines. The method of shading removal is based on a model of the architecture of the human colour vision system. Some image results are provided and the possible extension of the algorithm using a back-propagation neural network is discussed.
Texture Mapping Volume Objects
(The Eurographics Association, 2005) Shen, P.; Willis, P.; Mike Chantler
We present a combination of image-based texture mapping and projective space (pseudo-solid) texture. This imagebased texture mapping is useful for objects defined from volume datasets. The paper makes three main contributions. First, it introduces the combination of the image-based two-part texture mapping and projective space texture mapping for volume objects. Second, it presents a multi-resolution technique to overcome problems with projecting at glancing angles and to eliminate artifacts due to the resolution limitations. Third, it presents the pixel-level data-dependent interpolation technique in projective image warping. The proposed approach leads to superior quality of texture and thus provides an optional solution for texturing volume objects.The results show the effectiveness and quality of rendered images.
Sensitivity Analysis in Image Synthesis
(The Eurographics Association, 2005) Trujillo, M.; Izquierdo, E.; Mike Chantler
Intermediate virtual images are used in the evaluation of disparity estimations. The analysis is based on the effect of disparity inaccuracies in the relative quality of virtual images. The peak-signal-to-noise ratio and the percentage of visual errors are used to assess the quality of virtual images generated with distorted disparity fields. Computer simulation results show that the peak-signal-to-noise ratio is more affected by a small magnitude of perturbations two or three pixels than by a high frequency of perturbations 15% or 20%. However, the percentage of visual errors is more affected by the frequency of perturbations. By using distorted disparity fields, the deterioration in the quality of virtual images is imperceptible to the human eye.
Regularised Anisotropic Nonlinear Diffusion for Rendering Refraction in Volume Graphics
(The Eurographics Association, 2005) Rodgman, David; Chen, Min; Mike Chantler
Rendering refraction in volume graphics requires smoothly distributed normals to synthesise good quality visual representations. Such refractive visualisation is more susceptible to noise in the data than visualisations that do not involve refraction. In this paper, we addresses the need for improving the continuity of voxel gradients in discretely sampled volume datasets using nonlinear diffusion methods, which was originally developed for image denoising. We consider the necessity for minimising unnecessary geometrical distortion, detail the functional specification of a volumetric filter for regularised anisotropic nonlinear diffusion (R-ANLD), discuss the further improvements of the filter, and compare the efficacy of the filter with an anisotropic nonlinear diffusion (ANLD) filter as well as a Gaussian filter and a linear diffusion filter. Our results indicate that it is possible to make significant improvements in image quality in refractive rendering without excessive distortion.
Correspondenceless Stereo for 3-D Iris Location
(The Eurographics Association, 2005) Anderson, Tom; Trucco, Emanuele; Razeto, Marco; Mike Chantler
We present a correspondenceless stereo system locating the circular contour of an iris (limbus) in space, and therefore its 3-D plane. We avoid correspondence search completely by intersecting a bundle of conjugate epipolar lines with the elliptical images of the limbus in the stereo pair of images, which gives correspondences directly. The ellipses are located by active ellipse fitting. An efficient simulated annealing implementation achieves reliable iris location with uncontrolled illumination and eye or head movements. Tests with ground-truthed 3-D setups as well as real eye images indicate very good accuracy.
Visual Recognition of Man-made Materials and Structures in an Office Environment
(The Eurographics Association, 2005) Song, Y. Z.; Town, C. P.; Mike Chantler
This paper demonstrates a new approach towards object recognition founded on the development of Neural Network classifiers and Bayesian Networks. The mapping from segmented image region descriptors to semantically meaningful class membership terms is achieved using Neural Networks. Bayesian Networks are then employed to probabilistically detect objects within an image by means of relating region class labels and their surrounding environments. Furthermore, it makes use of an intermediate level of image representation and demonstrates how object recognition can be achieved in this way.
Color Reduction by Using a new Self-Growing and Self-Organized Neural Network
(The Eurographics Association, 2005) Atsalakis, A.; Papamarkos, N.; Mike Chantler
A new method for the reduction of the number of colors in a digital image is proposed. The new method is based on the developed of a new neural network classifier that combines the advantages of the Growing Neural Gas (GNG) and the Kohonen Self-Organized Feature Map (SOFM) neural networks. We call the new neural network: Self-Growing and Self- Organized Neural Gas (SGONG). Its main advantage is that it defines the number of the created neurons and their topology in an automatic way. As a consecutive, isolated color classes, which may correspond to significant image details, can be obtained. The SGONG is fed by the color components and additional spatial features. To speed up the entire algorithm and to reduce memory requirements, a fractal scanning sub-sampling technique is used. The method is applicable to any type of color images and it can accommodate any type of color space.
Merging Graphics and Vision for 3D Face Recognition
(The Eurographics Association, 2005) Bai, Li; Song, Yi; Mike Chantler
This paper presents a new approach to automatic 3D face modelling from unstructured point cloud data. An efficient B-Spline surface-fitting algorithm is used to obtain an initial parametric surface for each face point cloud data set. Knot vectors for each individual face surface are then standardised to produce a set of uniform knot vectors so that all the surfaces can be seen as fitted with the same set of knot vectors. Mapping from object space to shape space can then be established so that each 3D face can be described by a small number of shape descriptors. The use of shape descriptors allows automatic registration between face models. More importantly, it allows dynamic facial variation to be modelled and analysed via 3D warping, resulting in a powerful approach to quantifying the differences among individuals required for face recognition. 3D warping is often used in simulations in computer graphics. This paper explains, for the first time, how 3D warping can be exploited for face recognition based on multi-resolution analysis of warping fields. The methodology allows the quantitative study of variation in characteristics previously only described from a qualitative perspective.
Table of Contents and Preface
(The Eurographics Association, 2005) Mike Chantler
Advances in Shadow Removing for Motion Detection Algorithms
(The Eurographics Association, 2005) Spagnolo, P.; D'Orazio, T.; Leo, M.; Distante, A.; Mike Chantler
Detecting moving objects is very important in many application contexts such as people detection and recognition, visual surveillance, automatic generation of video effects, and so on. Motion detection algorithms are very sensible to light conditions; in particular they suffer the presence of shadows and sudden changes due to light switches. Here we propose an additional module that can be applied to a generic gray-level motion detection algorithm. The only requirement is the presence of a reference image (background model). The main idea of the proposed approach is that variations in light conditions alter the intensity values of pixels in the image, but the basic structures in the scene remain unchanged. The algorithm we propose is based on the correlation between regions selected from the reference image and the current one. The experiments have been performed on image sequences acquired both in indoor and outdoor environments with natural and artificial lights.
Talking Faces - Technologies and Applications
(The Eurographics Association, 2005) Ostermann, Jörn; Weissenfeld, Axel; Liu, Kang; Mike Chantler
Facial animation has been combined with text-to-speech synthesis to create innovative multimodal interfaces. In this lecture, we present the technology and architecture in order to use this multimodal interface in an web-based environment to support education, entertainment and e-commerce applications. Modern text to speech synthesizers using concatenative speech synthesis are able to generate high quality speech. Face animation uses the phoneme and timing information provided by such a speech synthesizer in order to animate the mouth. There are 2 basic technologies that are used to render talking faces: 3D face models as described in MPEG-4 may be used to provide the impression of a talking cartoon or human-like character. Sample-based face models generated from recorded video enable the synthesis of a talking head that cannot be distinguished from a real person. Depending on the chosen face animation technology and latency requirements, different architectures for delivering the talking head over the Internet are required for interactive applications. Keywords: Face animation, visual speech
Use of Computer Vision/ Computer Graphics Collaboration for 3D Rotoscopy
(The Eurographics Association, 2005) Gagalowicz, André; Mike Chantler
This talk introduces 3D rotoscopy and its role in post-production applications, and the computer vision/computer graphics strategies used. The case of rigid objects is presented first, for which well-established approaches can be used. The case of articulated objects is considered next, with special attention to the case of a full human body tracking (ignoring significant shape deformations introduced by baggy clothes). Results related to the tracking of professional golfers and face tracking, a challenging case of deformable objects, will be presented. The talk will be concluded by a presentation of further, possible applications of research done at the MIRAGES laboratory at INRIA Rocquencourt.
A New Framework for Trademark Retrieval Based on Size Functions
(The Eurographics Association, 2005) Cerri, A.; Ferri, M.; Giorgi, D.; Mike Chantler
We propose a new, effective system for Content Based trademark retrieval, which involves Size Functions. Three different classes of shape descriptors are combined, for a total amount of 25 measuring functions. The evaluation has been performed on a database of 1182 trademark images, provided by the UK Patent Office.

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