Browsing by Author "Echevarria, Jose"

Now showing 1 - 5 of 5
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    Efficient Image Vectorisation Using Mesh Colours
    (The Eurographics Association, 2021) Hettinga, Gerben Jan; Echevarria, Jose; Kosinka, Jiri; Frosini, Patrizio and Giorgi, Daniela and Melzi, Simone and RodolĂ , Emanuele
    Image vectorisation methods proposed in the past have not seen wide adoption due to performance, quality, controllability, and/or generality issues.We present a vectorisation method that uses mesh colours as a vector primitive for image vectorisation. We show that mesh colours have clear benefits for rendering performance and texture detail. Due to their flexibility, they also enable a simplified and more efficient generation of meshes of curved triangular patches, which are in our case constrained by our image feature extraction algorithm. The proposed method follows a standard pipeline where each step is efficient and controllable, leading to results that compare favourably with those from previous work. We show results over a variety of input images including photos, drawings, paintings, designs, and cartoons and also devise a user-guided vectorisation variant.
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    Generating Playful Palettes from Images
    (The Eurographics Association, 2019) DiVerdi, Stephen; Lu, Jingwan; Echevarria, Jose; Shugrina, Maria; Kaplan, Craig S. and Forbes, Angus and DiVerdi, Stephen
    Playful Palettes are a recent innovation in how artists can mix, explore, and choose colors in a user interface that combines the benefits of a traditional media painter's palette with non-destructive capabilities of digital tools. We present a technique to generate a Playful Palette that best represents the colors found in an input image, allowing the artist to select colors from the image's gamut, while maintaining full editability of the palette. We show that our approach outperforms recent work in terms of how accurately the image gamut is reproduced, and we present an approximation algorithm that is an order of magnitude faster with an acceptable loss in quality.
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    LoCoPalettes: Local Control for Palette-based Image Editing
    (The Eurographics Association and John Wiley & Sons Ltd., 2023) Chao, Cheng-Kang Ted; Klein, Jason; Tan, Jianchao; Echevarria, Jose; Gingold, Yotam; Ritschel, Tobias; Weidlich, Andrea
    Palette-based image editing takes advantage of the fact that color palettes are intuitive abstractions of images. They allow users to make global edits to an image by adjusting a small set of colors. Many algorithms have been proposed to compute color palettes and corresponding mixing weights. However, in many cases, especially in complex scenes, a single global palette may not adequately represent all potential objects of interest. Edits made using a single palette cannot be localized to specific semantic regions. We introduce an adaptive solution to the usability problem based on optimizing RGB palette colors to achieve arbitrary image-space constraints and automatically splitting the image into semantic sub-regions with more representative local palettes when the constraints cannot be satisfied. Our algorithm automatically decomposes a given image into a semantic hierarchy of soft segments. Difficult-to-achieve edits become straightforward with our method. Our results show the flexibility, control, and generality of our method.
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    Mesh Colours for Gradient Meshes
    (The Eurographics Association, 2021) Baksteen, Sarah D.; Hettinga, Gerben J.; Echevarria, Jose; Kosinka, Jiri; Frosini, Patrizio and Giorgi, Daniela and Melzi, Simone and RodolĂ , Emanuele
    We present an extension of the popular gradient mesh vector graphics primitive with the addition of mesh colours, aiming to reduce the mesh complexity needed to describe intricate colour gradients and textures. We present interesting applications to user-guided authoring of detailed vector graphics and image vectorisation.
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    Simulation of Dendritic Painting
    (The Eurographics Association and John Wiley & Sons Ltd., 2020) Canabal, José A.; Otaduy, Miguel A.; Kim, Byungmoon; Echevarria, Jose; Panozzo, Daniele and Assarsson, Ulf
    We present a new system for interactive dendritic painting. Dendritic painting is characterized by the unique and intricate branching patterns that grow from the interaction of inks, solvents and medium. Painting sessions thus become very dynamic and experimental. To achieve a compelling simulation of this painting technique we introduce a new Reaction-Diffusion model with carefully designed terms to allow natural interactions in a painting context. We include additional user control not possible in the real world to guide and constrain the growth of the patterns in expressive ways. Our multi-field model is able to capture and simulate all these complex phenomena efficiently in real time, expanding the tools available to the digital artist, while producing compelling animations for motion graphics.