CompAesth 15: Workshop on Computational Aesthetics

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https://diglib.eg.org/handle/10.2312/12609

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Browsing CompAesth 15: Workshop on Computational Aesthetics by Subject "I.3.3 [Computer Graphics]"

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    Computational Models for the Analysis and Synthesis of Graffiti Tag Strokes
    (The Eurographics Association, 2015) Berio, Daniel; Leymarie, Frederic Fol; Paul L. Rosin
    In this paper we describe a system aimed at the generation and analysis of graffiti tags.We argue that the dynamics of the movement involved in generating tags is in large part - and at a higher degree with respect to many other visual art forms - determinant of their stylistic quality. To capture this notion computationally, we rely on a biophysically plausible model of handwriting gestures (the Sigma Lognormal Model proposed by Réjean Plamondon et al.) that permits the generation of curves which are aesthetically and kinetically similar to the ones made by a human hand when writing. We build upon this model and extend it in order to facilitate the interactive construction and manipulation of digital tags. We then describe a method that reconstructs any planar curve or a sequence of planar points with a set of corresponding model parameters. By doing so, we seek to recover plausible velocity and temporal information for a static trace. We present a number of applications of our system: (i) the interactive design of curves that closely resemble the ones typically observed in graffiti art; (ii) the stylisation and beautification of input point sequences via curves that evoke a smooth and rapidly executed movement; (iii) the generation of multiple instances of a synthetic tag from a single example. This last application is a step in the direction of our longer term plan of realising a system which is capable of automatically generating convincing images in the graffiti style space.
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    Image Warping for a Painterly Effect
    (The Eurographics Association, 2015) Li, Jiayu; Mould, David; Paul L. Rosin
    We propose a two-stage approach to painterly rendering of photographs, where the image plane is first warped to produce a distorted or caricatured effect and then the resulting image is rendered with a painterly effect. We use SLIC superpixels to obtain an oversegmentation, and assign spring parameters uniformly to all pixels within a region; then, the mass-spring simulation distorts the plane in a random but content-sensitive way. With aggressive warping, the subsequent painterly rendering can be done lightly and need not remove much detail. The resulting renderings convey a sense of being painted and leave a sense of being handmade and not overly beholden to the photographic scene.
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    Painting with Flowsnakes
    (The Eurographics Association, 2015) Wyvill, Brian; Paul L. Rosin
    Space filling curves, invented by mathematicians in the 19th century, have long been a fascination for artists, however there are no interactive tools to allow an artist to create and explore various levels of recursion of the curve in different parts of the artwork. In this work a new type of painting tool for artists is introduced, which gives the artist control over the very base of a space filling curve, i.e recursive subdivision. Although there are many such curves that would lend themselves to this treatment, the Flowsnake (Gosper) curve has been chosen in this work, mainly for its aesthetics. The curve is based on a hexagonal grid, and in our system hexagons are subdivided at the artist's touch in a non-homogeneous manner, leaving a trail that forms the space filling curve. Some tools are introduced for controlling the painting, such as limiting the depth of recursion, and the 'slow brush', which interpolates slowly between subdivisions to allow the artist to stop at a chosen level. A set of space filling curve brush types provide different shapes and profiles, for giving the artist control of the nonhomogeneous subdivision, including the ability to un-subdivide the hexagons. An algorithm for drawing the curve non-recursively is introduced in order to produce a polyline suitable for processing on the GPU to make the system function at interactive rates. An animated version of the image can be made by replaying the subdivisions from the first level. Some examples made by art students and graduates are shown, along with the artist's comments on the system.