Non-Photorealistic Computer Graphics Library

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Found 10 item(s) authored by "John W. Buchanan" Find Author on Google.

Proceedings Comprehensive Halftoning of 3D Scenes
Oleg Veryovka, John W. Buchanan.
Skiggraph '99, 1999. [BibTeX]

Proceedings Computer-Generated Pencil Drawing
Mario Costa Sousa, John W. Buchanan.
Skiggraph '99, 1999. [BibTeX]

Proceedings Edge enhancement issues in halftoning
John W. Buchanan, Lisa M. Streit, Oleg Veryovka.
Graphics Interface (GI'98), pp. 209--216, 1998. [BibTeX]

Proceedings Halftoning with Image-Based Dither Screens
Oleg Veryovka, John W. Buchanan.
Graphics Interface (GI'99), 1999. [BibTeX]

Article Importance Driven Halftoning

Author(s): Lisa M. Streit, John W. Buchanan.
Article: Computer Graphics Forum (EG'98), Vol. 17, No. 3, 1998.
[BibTeX] Find this paper on Google

Most halftoning techniques have been primarily concerned with achieving an accurate reproduction of local grayscale intensities while avoiding the introduction of artifacts. A secondary concern in halftoning has been the preservation of edges in the halftoned image. In this paper, we will introduce a new halftoning technique that utilizes a bandpass pyramid to achieve an accurate reproduction of important attributes in the image. Ink is distributed through the bandpass pyramid primarily according to a user defined importance function. This technique has three main characteristics. First, our technique can produce results similar to many other halftoning techniques by allowing a generic importance function to be specified. If the chosen importance function is average intensity we obtain results similar to traditional halftoning. We also show how the importance function can be changed to highlight areas with high variance. Second, in addition to changing the importance function, the drawing primitives can also be changed. By using line segments instead of single pixels as drawing primitives we illustrate how edge enhancement can be achieved. Third, this technique allows the user to easily limit the number drawing primitives used. This is useful in limited resource rendering. In addition to providing a tailorable halftoning technique our method can easily be adapted to produce two tone non-photorealistic (NPR) images. We illustrate this by showing how sketched effects can be achieved by aligning the drawing primitives according to different image attributes.

Proceedings Non-photorealistic Rendering Using an Adaptive Halftoning Technique
Lisa M. Streit, Oleg Veryovka, John W. Buchanan.
Skiggraph '99, 1999. [BibTeX]

Proceedings Observational Model of Blenders and Erasers in Computer-Generated Pencil Rendering
Mario Costa Sousa, John W. Buchanan.
Proceedings of Graphics Interface (GI'99), pp. 157--166, 1999. [BibTeX]

Article Observational Models of Graphite Pencil Materials
Mario Costa Sousa, John W. Buchanan.
Computer Graphics Forum, Vol. 19, No. 1, pp. 27--49, March, 2000. [BibTeX]

Article Special Effects with Half-Toning
John W. Buchanan.
Computer Graphics Forum, Vol. 15, No. 3, pp. 97--108, 1996. [BibTeX]

Proceedings The edge buffer: A data structure for easy silhouette rendering
John W. Buchanan, Mario Costa Sousa.
1st International Symposium on Non-Photorealistic Animation and Rendering (NPAR'00), pp. 39--42, Annecy, France, June 05 - 07, 2000. [BibTeX]

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