Abstract:Fig. 1. Starting from a single random point, our dynamic illustration method creates high-quality stipple drawings with a small number of iterations (left to right: 12, 14, and 18 iterations). In the example shown above we end up with 36k points of constant size.We propose an adaptive version of Lloyd's optimization method that distributes points based on Voronoi diagrams. Our inspiration is the LindeBuzo-Gray-Algorithm in vector quantization, which dynamically splits Voronoi cells until a desired number of re… Show more
“…The purpose of point sampling is to dynamically generate a set of points that embodies specific properties. It can be used for stippling [MALI10,DSZ17,MAAI17], but also for rendering and texture synthesis. One common requirement is to match the spectral profile of blue noise, and consequently there have been many improvements to the state of the art in this area, such as improvements in computation [BWWM10, LNW∗10, CYC∗12], various properties [LWSF10, CGW∗13] and analysis [WW11].…”
While analysing and synthesising 2D distributions of points has been applied both to the generation of textures with discrete elements and for populating virtual worlds with 3D objects, the results are often inaccurate since the spatial extent of objects cannot be expressed. We introduce three improvements enabling the synthesis of more general distributions of elements. First, we extend continuous pair correlation function (PCF) algorithms to multi‐class distributions using a dependency graph, thereby capturing interrelationships between distinct categories of objects. Second, we introduce a new normalised metric for disks, which makes the method applicable to both point and possibly overlapping disk distributions. The metric is specifically designed to distinguish perceptually salient features, such as disjoint, tangent, overlapping, or nested disks. Finally, we pay particular attention to convergence of the mean PCF as well as the validity of individual PCFs, by taking into consideration the variance of the input. Our results demonstrate that this framework can capture and reproduce real‐life distributions of elements representing a variety of complex semi‐structured patterns, from the interaction between trees and the understorey in a forest to droplets of water. More generally, it applies to any category of 2D object whose shape is better represented by bounding circles than points.
“…The purpose of point sampling is to dynamically generate a set of points that embodies specific properties. It can be used for stippling [MALI10,DSZ17,MAAI17], but also for rendering and texture synthesis. One common requirement is to match the spectral profile of blue noise, and consequently there have been many improvements to the state of the art in this area, such as improvements in computation [BWWM10, LNW∗10, CYC∗12], various properties [LWSF10, CGW∗13] and analysis [WW11].…”
While analysing and synthesising 2D distributions of points has been applied both to the generation of textures with discrete elements and for populating virtual worlds with 3D objects, the results are often inaccurate since the spatial extent of objects cannot be expressed. We introduce three improvements enabling the synthesis of more general distributions of elements. First, we extend continuous pair correlation function (PCF) algorithms to multi‐class distributions using a dependency graph, thereby capturing interrelationships between distinct categories of objects. Second, we introduce a new normalised metric for disks, which makes the method applicable to both point and possibly overlapping disk distributions. The metric is specifically designed to distinguish perceptually salient features, such as disjoint, tangent, overlapping, or nested disks. Finally, we pay particular attention to convergence of the mean PCF as well as the validity of individual PCFs, by taking into consideration the variance of the input. Our results demonstrate that this framework can capture and reproduce real‐life distributions of elements representing a variety of complex semi‐structured patterns, from the interaction between trees and the understorey in a forest to droplets of water. More generally, it applies to any category of 2D object whose shape is better represented by bounding circles than points.
“…For example, halftoning is the process of generating a pattern of binary pixels that creates the illusion of a continuous‐tone image . Closely related is stippling where dots are drawn, both digitally or physically, in such a way that it looks like a target photo. Another interesting work is the generation of a QR code resembling an input image .…”
Creating objects with threads is commonly referred to as string art. It is typically a manual, tedious work reserved for skilled artists. In this paper, we investigate how to automatically fabricate string art pieces from one single continuous thread in such a way that it looks like an input image. The proposed system consists of a thread connection optimization algorithm and a custom‐made fabrication machine. It allows casual users to create their own personalized string art pieces in a fully automatic manner. Quantitative and qualitative evaluations demonstrated our system can create visually appealing results.
“…To summarize, the amount of distributed points and their respective size depend on the tone, texture, and the local importance. We use the stippling algorithm of Deussen et al (2017) due to its ability to locally vary the degree of abstraction while avoiding visual artefacts such as distracting regularities within the point sets (Deussen et al 2000;Secord 2002). The algorithm uses the original image and its corresponding grayscale CAM as input.…”
“…Hence, it is directly correlated to the local importance. The algorithm of Deussen et al (2017) dynamically distributes points with given sizes to match the local tonal value of the input image. Using grayscale CAMs allows a direct linear mapping from importance [0;1] to point size [min;max].…”
Within this paper we propose an end-to-end approach for classifying terrestrial images of building facades into five different utility classes (<i>commercial, hybrid, residential, specialUse, underConstruction</i>) by using Convolutional Neural Networks (CNNs). For our examples we use images provided by Google Street View. These images are automatically linked to a coarse city model, including the outlines of the buildings as well as their respective use classes. By these means an extensive dataset is available for training and evaluation of our Deep Learning pipeline. The paper describes the implemented end-to-end approach for classifying street-level images of building facades and discusses our experiments with various CNNs. In addition to the classification results, so-called Class Activation Maps (CAMs) are evaluated. These maps give further insights into decisive facade parts that are learned as features during the training process. Furthermore, they can be used for the generation of abstract presentations which facilitate the comprehension of semantic image content. The abstract representations are a result of the stippling method, an importance-based image rendering.
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