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Reynold Bailey

Simulating Real Paint: A Non-Photorealistic Approach. Reynold Bailey. Outline. Motivation Statement of Problem Previous Work Techniques Results Challenges and Future Work. Motivation. void ShapesUI::resize(int width, int height) { glViewport(0, 0, width, height);

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Reynold Bailey

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  1. Simulating Real Paint: A Non-Photorealistic Approach Reynold Bailey

  2. Outline Motivation Statement of Problem Previous Work Techniques Results Challenges and Future Work Washington University in St. Louis Media & Machines Lab

  3. Motivation void ShapesUI::resize(int width, int height) { glViewport(0, 0, width, height); glMatrixMode(GL_PROJECTION); glLoadIdentity(); gluPerspective(60, (GLfloat) width /(GLfloat) height, 0.1, 4.0); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); gluLookAt(0.0, 0.0, 2.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0); } void ShapesUI::draw() { glClear(GL_COLOR_BUFFER_BIT); switch (display) { case DISPLAY_WIREFRAME: { glDisable(GL_LIGHTING); glPolygonMode(GL_FRONT, GL_LINE); glColor3f(0.0f, 0.0f, 0.0f); } break; case DISPLAY_FLAT_SHADING: { glEnable(GL_LIGHTING); glPolygonMode(GL_FRONT, GL_FILL); glColor3f(1.0f, 1.0f, 1.0f); glShadeModel(GL_FLAT); Washington University in St. Louis Media & Machines Lab

  4. Motivation Contrast control in Photoshop Artist use of contrast Washington University in St. Louis Media & Machines Lab

  5. Problem Statement “Simulating Real Paint Blends and Variations” Exploration of techniques to capture, analyze and manipulate data from actual paint samples. Exploration of techniques to apply captured “paint” to a 3D computer generated model. Washington University in St. Louis Media & Machines Lab

  6. Current Color Representation and Use RGB color space Hardware oriented Difficult to pick and name colors Uniform colors - no method for specifying statistical variation. HSV color space User oriented – Based on artistic notion of tint, shade and tone Easier to pick colors Uniform colors - no way to specifying statistical variation. Washington University in St. Louis Media & Machines Lab

  7. Previous Work Color Palette Plug-in for Adobe Illustrator Anne Spatler Brown University Barbara Meier Brown University The Lit Sphere: A Model for Capturing NPR Shading from Art Peter-Pike J. Sloan Microsoft Research William Martin University of Utah Amy Gooch University of Utah Bruce Gooch University of Utah Washington University in St. Louis Media & Machines Lab

  8. Previous Work: Color Palette Plug-in Simulate a real artist’s palette Select initial colors Create blends by drawing a line between colors. Use colors from the generated blends. Provide automated palettes Washington University in St. Louis Media & Machines Lab

  9. Previous Work: The Lit Sphere Typical example of a shading study Easily transferred to computer graphics: (Paint by normals) Washington University in St. Louis Media & Machines Lab

  10. Previous Work: The Lit Sphere The Lit Sphere approach: Capture shading model from existing art and store the shading information on a sphere Use the captured shading information to shade other models (application of paint by normals). Washington University in St. Louis Media & Machines Lab

  11. Previous Work: The Lit Sphere The Lit Sphere Results Washington University in St. Louis Media & Machines Lab

  12. Color Blending in Real Paints Red – Green Blend Using RGB Red – Green Blend Real Paints Washington University in St. Louis Media & Machines Lab

  13. Data Capture - Histogram Representation Count 0 1 Intensity Washington University in St. Louis Media & Machines Lab

  14. First Steps Washington University in St. Louis Media & Machines Lab

  15. Histogram Shifting Technique System limited by number of samples scanned. Store average RGB for all generated histograms. Given desired RGB, search for closest histogram. Shift each bin within that histogram to obtain a new histogram. RGB (new bin) = RGB (old bin) + (Desired RGB – Average RGB (old hist)) Washington University in St. Louis Media & Machines Lab

  16. 3D Rendering – Traditional Approach Each object in scene is assigned a single color Scale color by: ^ ^ ^ n ^ I = < N , L > + < R , V > Diffuse Specular (optional) N L R V Washington University in St. Louis Media & Machines Lab

  17. 3D Rendering – Our Approach + dark light = Washington University in St. Louis Media & Machines Lab

  18. 3D Rendering – Our Approach Artists paint in layers Under painting – Represents the overall desired tone of the scene. Base painting – Paint all objects in desired color. Highlights – Add highlights and details to enhance painting. Washington University in St. Louis Media & Machines Lab

  19. 3D Rendering – Our Approach Under paint Base paint Highlights Washington University in St. Louis Media & Machines Lab

  20. 3D Rendering – Our Approach Composite Image Highlights – Blend base paint and highlights. ^ ^ < R , V > > 0 Under painting – Blend base paint and under paint. ^ ^ - < N , L > > 0 All other regions – Display the base paint. Washington University in St. Louis Media & Machines Lab

  21. 3D Rendering – Our Approach Highlights Composite Image Under paint Base paint Washington University in St. Louis Media & Machines Lab

  22. 3D Rendering – Our Approach Washington University in St. Louis Media & Machines Lab

  23. Challenges Achieved color coherency with scanned paint samples. Not achieved spatial coherency. Only first order statistics collected from paint samples. Washington University in St. Louis Media & Machines Lab

  24. Possible Solutions / Future Work Capture Texture in addition to color. Stretching the sample to fit the surface. May distort brush strokes. Frame to frame coherency. Washington University in St. Louis Media & Machines Lab

  25. Spatial Coherency - First Attempts Washington University in St. Louis Media & Machines Lab

  26. Demo Washington University in St. Louis Media & Machines Lab

  27. Questions ?? Washington University in St. Louis Media & Machines Lab

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