Free form deformation based face cartoon stylization

A novel free form based face cartoon stylization method is presented in this paper. First, a face cartoon library with marked feature points is constructed. And then select the input image as the target image and an appropriate cartoon image from cartoon library as the reference image, apply the deformation between the corresponding feature points of the images to the target image. Finally, we apply an image stylization process to the result image. As an alternative method, we also choose an appropriate cartoon image as the target image and the input image as the reference image to apply the free from deformation. The experimental results show that our method is straightforward and quick with diversified styles, delivering more infection.

Automated pebble mosaic stylization of images

Digital mosaics have usually used regular tiles, simulating historical tessellated mosaics. In this paper, we present a method for synthesizing pebble mosaics, a historical mosaic style in which the tiles are rounded pebbles. We address both the tiling problem,of distributing pebbles over the image plane so as to approximate the input image content, and the problem of geometry, creating a smooth rounded shape for each pebble. We adopt simple linear iterative clustering(SLIC)to obtain elongated tiles conforming to image content,and smooth the resulting irregular shapes into shapes resembling pebble cross-sections. Then, we create an interior and exterior contour for each pebble and solve a Laplace equation over the region between them to obtain height-field geometry. The resulting pebble set approximates the input image while representing full geometry that can be rendered and textured for a highly detailed representation of a pebble mosaic.

The Situational Variation and Aesthetic Features of Chinese Traditional Drama

As a specific name,Chinese traditional drama appeared in the 1960s,which specifically refers to the reserved plays of various traditional dramas that coexisted with modern dramas and newly edited historical dramas before the foundation of New China.Traditional drama has aesthetic characteristics such as freehand,stylization,singing and dancing,and it has profoundly affected the aesthetic taste of the Chinese people because of its rich spiritual and aesthetic accumulation.

An empirical behavioral order‑driven model with price limit rules

We propose an empirical behavioral order-driven(EBOD)model with price limit rules,which consists of an order placement process and an order cancellation process.All the ingredients of the model are determined based on the empirical microscopic regularities in the order flows of stocks traded on the Shenzhen Stock Exchange.The model can reproduce the main stylized facts in real markets.Computational experiments unveil that asymmetric setting of price limits will cause the stock price to diverge exponentially when the up price limit is higher than the down price limit and to vanish vice versa.We also find that asymmetric price limits have little influence on the correlation structure of the return series and the volatility series,but cause remarkable changes in the average returns and the tail exponents of returns.Our EBOD model provides a suitable computational experiment platform for academics,market participants,and policy makers.

Some Stylized Facts of Short-Term Stock Prices of Selected Nigerian Banks

This paper examines presence of some stylized facts of short-term stock prices in the banking sector of the Nigerian Stock Market (NSM). Non-normality, lack of autocorrelation in the returns at first lag and significant positive autocorrelation in higher magnitude returns, widely studied in other markets, are investigated using daily closing stock prices of the four major Nigerian banks (Access, First, Guaranty Trust and United Bank for Africa (UBA)), from 2001 to 2013;encompassing periods of different financial scenarios. Jarque-Bera (JB), Doonik-Hansen, Kolmogrov-Smirnov and Ljung-Box (Q) test statistics are applied. Our findings reveal that the four banks stocks behave slightly different, but generally possess the stylized facts found in other markets. Observed is that, while the distributions of the returns for two of these banks (First and UBA) are approximately symmetric and leptokurtic;those of Access and Guaranty Trust banks are significantly non-symmetric and leptokurtic, thus non-normally distributed. Also established is that, while autocorrelation functions of daily returns are either negative or zero, those of both absolute returns and the squared returns are mostly positive. The autocorrelations of absolute returns are found to be predominantly positive and more persistent than those of the squared returns;indicating volatility clustering. Consequently, we conclude that the short-term stock prices of these banks behave like those of other markets. Some implications of the results for financial investment and stock market behaviour in the banking sector of NSM are discussed.

REBOL程序设计初体验（6）——VID之一

本篇是系列文章的第六篇，介绍一个很有趣的主题：VID。过去这几个月以来，从读者的反应中，发现不少人对REBOL感兴趣，但是许多读者仍有错误的期待，以为通过REBOL可以很快地学会程序设计。我们总希望不用蹉马步就立刻成为飞檐走壁的武林高手；不用背单字词就变成无字不识的英文专家；

Expressive line drawings of human faces from range images

We propose a novel technique to extract features from a range image and use them to produce a 3D pen-and-ink style portrait similar to a traditional artistic drawing. Unlike most previous template-based, component-based or example-based face sketching methods, which work from a frontal photograph as input, our system uses a range image as input. Our method runs in real-time for models of moderate complexity, allowing the pose and drawing style to be modified interactively. Portrait drawing in our system makes use of occluding contours and suggestive contours as the most important shape cues. However, current 3D feature line detection methods require a smooth mesh and cannot be reliably applied directly to noisy range images. We thus present an improved silhouette line detection algorithm. Feature edges related to the significant parts of a face are extracted from the range image, connected, and smoothed, allowing us to construct chains of line paths which can then be rendered as desired. We also incorporate various portrait-drawing principles to provide several simple yet effective non- photorealistic portrait renderers such as a pen-and-ink shader, a hatch shader and a sketch shader. These are able to generate various life-like impressions in different styles from a user-chosen viewpoint. To obtain satisfactory results, we refine rendered output by smoothing changes in line thickness and opacity. We are careful to provide appropriate visual cues to enhance the viewer＇s comprehension of the human face. Our experimental results demonstrate the robustness and effectiveness of our approach, and further suggest that our approach can be extended to other 3D geometric objects.

NPRportrait 1.0:A three-level benchmark for non-photorealistic rendering of portraits

Recently,there has been an upsurge of activity in image-based non-photorealistic rendering(NPR),and in particular portrait image stylisation,due to the advent of neural style transfer(NST).However,the state of performance evaluation in this field is poor,especially compared to the norms in the computer vision and machine learning communities.Unfortunately,the task of evaluating image stylisation is thus far not well defined,since it involves subjective,perceptual,and aesthetic aspects.To make progress towards a solution,this paper proposes a new structured,threelevel,benchmark dataset for the evaluation of stylised portrait images.Rigorous criteria were used for its construction,and its consistency was validated by user studies.Moreover,a new methodology has been developed for evaluating portrait stylisation algorithms,which makes use of the different benchmark levels as well as annotations provided by user studies regarding the characteristics of the faces.We perform evaluation for a wide variety of image stylisation methods(both portrait-specific and general purpose,and also both traditional NPR approaches and NST)using the new benchmark dataset.

A Novel Variational Image Model： Towards a Unified Approach to Image Editing

In this paper we propose a unified variational image editing model. It interprets image editing as a variational problem concerning the adaptive adjustments to the zero- and first-derivatives of the images which correspond to the color and gradient items. By varying the definition domain of each of the two items as well as applying diverse operators, the new model is capable of tackling a variety of image editing tasks. It achieves visually better seamless image cloning effects than existing approaches. It also induces a new and efficient solution to adjusting the color of an image interactively and locally. Other image editing tasks such as stylized processing, local illumination enhancement and image sharpening, can be accomplished within the unified variational framework. Experimental results verify the high flexibility and efficiency of the proposed model.

Heterogeneous Round-Trip Trading and the Emergence of Volatility Clustering in Speculation Game

This study is a detailed analysis of Speculation Game,a simple agent-based model of financial markets,in which the round-trip trading and the dynamic wealth evolution with variable trading volumes are implemented.Instead of herding behavior,the authors find that the heterogeneous holding periods in round-trip trades can contribute to the emergence of volatility clustering.In particular,the spontaneous redistribution of market wealth through repetitions of round-trip trades with non-uniform horizons can widen the wealth disparity and establish the Pareto distribution of the capital size.As a result,the intermittent placements of relatively big orders from endogenously emerged rich traders can bring on large fluctuations in price return.Empirical data are used to support the scenario derived from the model.

Stylized strokes for coherent line drawings

Temporal coherence is one of the central challenges for rendering a stylized line. It is especially difficult for stylized contours of coarse meshes or nonuniformly sampled models, because those contours are polygonal feature edges on the models with no continuous correspondences between frames. We describe a novel and simple technique for constructing a 2D brush path along a 3D contour. We also introduce a 3D parameter propagation and re-parameterization procedure to construct stroke paths along the 2D brush path to draw coherently stylized feature lines with a wide range of styles. Our method runs in real-time for coarse or non-uniformly sampled models, making it suitable for interactive applications needing temporal coherence.