Color contoning for 3D printing

Abstract

Appearance reproduction is an important aspect of 3D printing. Current color reproduction systems use halftoning methods that create colors through a spatial combination of different inks at the object's surface. This introduces a variety of artifacts to the object, especially when viewed from a closer distance. In this work, we propose an alternative color reproduction method for 3D printing. Inspired by the inherent ability of 3D printers to layer different materials on top of each other, 3D color contoning creates colors by combining inks with various thicknesses inside the object's volume. Since inks are inside the volume, our technique results in a uniform color surface with virtually invisible spatial patterns on the surface. For color prediction, we introduce a simple and highly accurate spectral model that relies on a weighted regression of spectral absorptions. We fully characterize the proposed framework by addressing a number of problems, such as material arrangement, calculation of ink concentration, and 3D dot gain. We use a custom 3D printer to fabricate and validate our results.

Scattering-aware texture reproduction for 3D printing

“…Qualitatively the direct mode is compatible with other state-of-theart 3D color reproduction pipelines [Babaei et al 2017;Brunton et al 2015], although it needs be noted that our solution has a markedly di erent technical basis consistent within our scatteringaware optimization as a whole. We now delineate the steps involved in our reproduction pipeline (also refer to Fig.…”

“…To provide a comparison for our optimized results, we use unsharp masking to enhance the targets and print them in the default texture print mode. This is compatible with the treatment of Babaei et al [2017]; we also use an equivalent method to estimate the sharpening kernel.…”

“…Few works model the e ect of lateral (subsurface) scattering in the material, and most assume it to be a spatially uniform blur that attenuates high frequencies across the surface. The resulting translucent appearance is taken as a welcomed e ect [Brunton et al 2015], kept to a minimum through speci cally designed printing materials [Babaei et al 2017], and/or is approximately compensated for by de-convolution [Babaei et al 2017] or through an adaptation of unsharp-masking [Cignoni et al 2008;Pintus et al 2010].…”

“…An interesting alternative would be combining our method with the recent contoning technique of Babaei et al [2017], to suppress the quantization noise inherent to any half-toning. We see this as an interesting direction for future work.…”

Gloss, Color, and Topography Scanning for Reproducing a Painting’s Appearance Using 3D Printing

“…Limitations of these systems are the limited print area (max. 490 mm × 390 mm), and the translucency of the inks, leading to blurring of fine details, and the need to digitally compensate for these effects, in turn resulting in a lower effective resolution [7,14,23,24]. Other approaches to physical appearance reproduction of paintings use a hybrid fabrication technique, combining plaster casting, 2D color printing, and artisan hand painting and varnishing to create life-like reproductions [31,70].…”