Automatic Generation of Stippling Illustrations from two Photographs

[EN] In this paper we present a software tool that is able to reconstruct the depth field of the objects from two photographs and to obtain a pseudo 3D model. Using this information our system is able to difference background from foreground, and therefore, what are the interesting elements in the photographs and stipple them in different ways.This tool needs almost no user interaction. The user simply has to align both photographs and indicate the level of detail according to the distance. The rest is decided by our software. Whereas a professional illustrator needs more than 20 hours to finish a similar illustration, our software is able to do it in just few seconds.[ES] En este artículo se presenta una herramienta que, a partir de dos fotografías, es capaz de reconstruir la profundidad de los objetos y obtener un modelo 2D y medio. Utilizando dicha información el sistema es capaz de diferenciar qué es fondo y qué un elemento de interés y puntearlos de forma distinta para generar la ilustración final.La herramienta necesita una mínima interacción por parte del usuario para alinear ambas fotografías e indicarle el nivel de detalle a partir de cierta lejanía. El resto es decidido por el software que se encarga de generar la ilustración. Dicha ilustración es generada en pocos segundos por el sistema, mientras que un ilustrador profesional puede tardar aproximadamente 20 horas para realizar el mismo tipo de ilustración.Thanks to Consejería de Innovación y Empresa of the Junta de Andalucía that has partially funded this article throw the project of excelency PE09-TIC-5276.Arroyo, G.; Martín, D.; Luzón, MV. (2012). Automatic Generation of Stippling Illustrations from two Photographs. Virtual Archaeology Review. 3(5):89-92. https://doi.org/10.4995/var.2012.4530OJS899235BARLA, P. et al. (2006): "Interactive hatching and stippling by example". INRIA.DALAL, K. et al. (2006): "A Spectral Approach to NPR Packing". In Proc. of NPAR, ACM, New York, pp. 71-78. http://dx.doi.org/10.1145/1124728.1124741DEUSSEN O. et al. (2000): "Floating points: A method for computing stipple drawings". Computer Graphics Forum 19, pp. 40-51. http://dx.doi.org/10.1111/1467-8659.00396HILLER, S. et al. (2003): "Beyond Stippling - Methods for Distributing Objects on the Plane". Computer Graphics Forum 22, 3, September, pp. 515-522. http://dx.doi.org/10.1111/1467-8659.00699ISENBERG, T. et al. (2005): "Breaking the Pixel Barrier". In Proc. of Cae, Eurographics Association, Aire-la-Ville, Switzerland, pp. 41-48.KIM, S. et al. (2009): "Stippling By Example". In Proc. of NPAR, ACM, New York, pp. 41-50. http://dx.doi.org/10.1145/1572614.1572622MACIEJEWSKI R. et al. (2008): "Measuring Stipple Aesthetics in Hand-Drawn and Computer-Generated Images", IEEE Computer Graphics and Applications, pp. 62-74. http://dx.doi.org/10.1109/MCG.2008.35MOULD D. (2007): "Stipple placement using distance in a weighted graph". In Proc. of Computational Aesthetics in Graphics, no. 3. p. unknown.SCHLECHTWEG S. et al. (2005): "Renderbots: Multi agent systems for direct image generation" Computer Graphics Forum 24, pp 283-290. http://dx.doi.org/10.1111/j.1467-8659.2005.00838.xSECORD A. et al. (2002): "Fast primitive distribution for illustration". In Thirteenth Eurographics Workshop on Rendering, pp. 215-226.SECORD, A. (2002): "Weighted voronoi stippling". In Proc. of NPAR, ACM Press, pp. 37-43. http://dx.doi.org/10.1145/508530.50853

Stippling by Example

In this work, we focus on stippling as an artistic style and discuss our technique for capturing and reproducing stipple features unique to an individual artist. We employ a texture synthesis algorithm based on the gray-level co-occurrence matrix (GLCM) of a texture field. This algorithm uses a texture similarity metric to generate stipple textures that are perceptually similar to input samples, allowing us to better capture and reproduce stipple distributions. First, we extract example stipple textures representing various tones in order to create an approximate tone map used by the artist. Second, we extract the stipple marks and distributions from the extracted example textures, generating both a lookup table of stipple marks and a texture representing the stipple distribution. Third, we use the distribution of stipples to synthesize similar distributions with slight variations using a numerical measure of the error between the synthesized texture and the example texture as the basis for replication. Finally, we apply the synthesized stipple distribution to a 2D grayscale image and place stipple marks onto the distribution, thereby creating a stippled image that is statistically similar to images created by the example artist

Generation of automatic stippling illustrations from photographs for documenting archaeological pieces

[EN] Hand-made stippling has been used frequently in the process of drawing illustrations for documenting archaeological pieces. This is due to the fact that this technique represents in an efficient way shapes, tones, and textures, by means of distributing dots on the paper. The process of stippling has needed traditionally the ability of an artist, who usually produces the illustration from photographs. In this paper, a program that generates stippling illustrations of high quality is presented. The developed interface makes possible that any user can generate illustrations without the need of artistic abilities. The program is able to work in realtime, allowing the user interacts with the program. We have developed several artistic techniques in high level tasks that allow to improve the final results.[ES] El punteado manual se ha utilizado frecuentemente en el proceso de ilustración para documentar piezas arqueológicas. Esto se debe a que esta técnica es capaz de representar de forma eficiente formas, tonalidades y texturas mediante la distribución de puntos en un papel. Estas ilustraciones requieren las habilidades de un artista, el cual utiliza fotografías para realizarlas. En este artículo se presenta un software que genera ilustraciones punteadas de alta calidad de forma automática. La interfaz desarrollada hace posible que cualquier usuario pueda generar ilustraciones sin la necesidad de habilidades artísticas. El programa trabaja en tiempo real permitiendo al usuario interactuar con el mismo. Hemos implementado varias técnicas empleadas por artistas como simples tareas de alto nivel que mejoran los resultados finales.Authors thank the collaboration of the illustrator Elena Piñar. Thanks to the Ministerio de Educación y Ciencia of Spain for the projects TIN2007-67474-C03-02 and TIN2007-67474-C03-01, which have partially funded this work.Arroyo, G.; Martín, D.; Luzón, MV. (2011). Generation of automatic stippling illustrations from photographs for documenting archaeological pieces. Virtual Archaeology Review. 2(3):59-64. https://doi.org/10.4995/var.2011.4606OJS596423SECORD, A. (2002): "Weighted voronoi stippling". In Proc. of NPAR, ACM Press, pp. 37-43. http://dx.doi.org/10.1145/508530.508537DEUSSEN O. et al. (2000): "Floating points: A method for computing stipple drawings". Computer Graphics Forum 19, pp. 40-51. http://dx.doi.org/10.1111/1467-8659.00396HILLER, S. et al. (2003): "Beyond Stippling - Methods for Distributing Objects on the Plane". Computer Graphics Forum 22, 3, September, pp. 515-522. http://dx.doi.org/10.1111/1467-8659.00699DALAL, K. et al. (2006): "A Spectral Approach to NPR Packing". In Proc. of NPAR, ACM, New York, pp. 71-78. http://dx.doi.org/10.1145/1124728.1124741BARLA, P. et al. (2006): "Interactive hatching and stippling by example". INRIA.SECORD A. et al. (2002): "Fast primitive distribution for illustration". In Thirteenth Eurographics Workshop on Rendering, pp. 215-226.SCHLECHTWEG S. et al. (2005): "Renderbots: Multi agent systems for direct image generation". Computer Graphics Forum 24, 283-290. http://dx.doi.org/10.1111/j.1467-8659.2005.00838.xMOULD D. (2007): "Stipple placement using distance in a weighted graph". In Proc. of Computational Aesthetics in Graphics, no. 3. p. unknown.KIM, S. et al. (2009): "Stippling By Example". In Proc. of NPAR, ACM, New York, pp. 41-50. http://dx.doi.org/10.1145/1572614.1572622ISENBERG, T. et al. (2005): "Breaking the Pixel Barrier". In Proc. of Cae, Eurographics Association, Aire-la-Ville, Switzerland, pp. 41-48.MACIEJEWSKI R. et al. (2008): "Measuring Stipple Aesthetics in Hand-Drawn and Computer-Generated Images", IEEE Computer Graphics and Applications, pp. 62-74. http://dx.doi.org/10.1109/MCG.2008.3

Automated Hedcut Illustration Using Isophotes

Abstract. In this work, we present an automated system for creat-ing hedcut illustrations, portraits rendered using small image feature aligned dots (stipples). We utilize edge detection and shading cues from the input photograph to direct stipple placement within the image. Both image edges and isophotes are extracted as a means of describing the image feature and shading information. Edge features and isophotes are then assigned different priorities, with isophotes being assigned the high-est priority to enhance the depth perception within the hedcut portrait. Priority assignment dictates the stipple alignment and spacing. Finally, stipple size is based on the number of points and intensity and the gra-dient magnitude of the input image.

Automated pebble mosaic stylization of images

Digital mosaics have usually used regular tiles, simulating the historical "tessellated" mosaics. In this paper, we present a method for synthesizing pebble mosaics, a historical mosaic style in which the tiles are rounded pebbles. We address both the tiling problem, where pebbles are distributed over the image plane so as to approximate the input image content, and the problem of geometry, creating a smooth rounded shape for each pebble. We adapt SLIC, simple linear iterative clustering, to obtain elongated tiles conforming to image content, and smooth the resulting irregular shapes into shapes resembling pebble cross-sections. Then, we create an interior and exterior contour for each pebble and solve a Laplace equation over the region between them to obtain height-field geometry. The resulting pebble set approximates the input image while presenting full geometry that can be rendered and textured for a highly detailed representation of a pebble mosaic