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Pencil Drawing Production Cewu Lu, Li Xu, Jiaya Jia
Speaker: Ying-Jou Chen
AmazingDSP
Proposed Approach
• Line Drawing• Tone Mapping
Line Drawing
• Idea… contour might be related…
Sobel Filter
Edge?
Not enough…
Line DrawingNot Simply Edges…
Line Drawing- Curve
• Idea… direction detection
Line Drawing- Line Crossing
• Idea… CONVOLUTION• Effect of extension
Line Drawing
⨂ ⨂ ⨂
+¿ +¿
Line Drawing
⨂ ⨂ ⨂
+¿ +¿
Magically….
DONE!
Tone Mapping
Histogram
Histogram
# of pixels
pixel value
Pencil ToneNatural Tone
Histogram Equalization
Tone Mapping
• Model the shape by….
Laplacian Distribution
Uniform Distribution
Gaussian Distribution
Pencil ToneNatural Tone
DONE!DONE!
Texture Rendering
Pencil Texture Rock Texture Chinese Drawing Texture
Texture Rendering
𝜷=𝟎 .𝟐𝜷=𝟎 .𝟔
𝜷=𝟏 .𝟎𝜷=𝟏 .𝟒
Texture Rendering
To each pixel, we hope that…
𝑷 (𝒙) 𝑱 (𝒙)
Pencil Tone
𝑷 (𝒙)𝜷( 𝒙)≈ 𝑱 (𝒙)
Texture Rendering
Smooth
𝜷∗
Other examples
Reference
• "Combining Sketch and Tone for Pencil Drawing Production", Cewu Lu, Li Xu, Jiaya Jia , International Symposium on Non-Photorealistic Animation and Rendering (NPAR 2012), June, 2012