In this paper, the current technologies in full colour 3D printing technology were introduced. A framework of colour image reproduction process for 3D colour printing is proposed. A special focus was put on colour management for 3D printed objects. Two approaches, colorimetric colour reproduction and spectral based colour reproduction are proposed in order to faithfully reproduce colours in 3D objects. Two key studies, colour reproduction for soft tissue prostheses and colour uniformity correction across different orientations are described subsequently. Results are clear shown that applying proposed colour image reproduction framework, performance of colour reproduction can be significantly enhanced. With post colour corrections, a further improvement in colour process are achieved for 3D printed objects.
The purpose of our experiments was to investigate the effect of interaxial camera separation on the perceived shape and
viewing comfort of 3D images. Horizontal Image Translation (HIT) and interaxial distance were altered together.
Following Banks et al (2009), our stimuli were simple stereoscopic hinges and we measured the perceived angle as a
function of camera separation. We compared the predictions based on ray tracing with the perceived 3D shape obtained
psychophysically. 40 participants were asked to judge the angles of 250 hinges at different camera separations
(interaxial and HIT linked a 20-100mm; angle range: 50°-130°). Comfort data was obtained using a five point Likert
scale. Stimuli were presented in orthoscopic conditions with screen and observer Field of View (FOVO) matched at 45°.
Our main results are: (1) For the 60mm camera separation, observers perceived a right angle correctly, but at other
camera separations right angles were perceived as larger than 90° (camera separations > 60mm) or smaller than 90°
(camera separations < 60 mm). (2) The observed perceptual deviations from a right angle were smaller than predicted
based on disparity information (ray tracing model) alone. (3) We found an interaction between comfort and camera
separation: only at the 60mm camera separation (e.g. at typical human eye separation) do we find a significant negative
correlation between angle and comfort. All other camera separations, the disparity (angle) has no systematic effect on
comfort. This research is set out to provide a foundation for tolerance limits for comfort and perceptual distortions
brought about by various virtual camera separations.
The aim of the ColorFest is to extend the original ModelFest (http://vision.arc.nasa.gov/modelfest/) experiments to build a spatio-chromatic standard observer for the detection of static coloured images. The two major issues that need to be addressed are (1) the contrast sensitivity functions for the three chromatic mechanisms and (2) how the output of these channels is combined. We measured detection thresholds for stimuli modulated along different colour directions and for a wide range of spatial frequencies. The three main directions (an achromatic direction, a nominally isoluminant red-green direction, and the tritanopic confusion line) and four intermediate colour directions were used. These intermediate directions were the vector sums of the thresholds along the main directions. We evaluate two models. Detection performance is described by a linear transformation C defining the chromatic tuning and a diagonal matrix S reflecting the sensitivity of the chromatic mechanisms for a particular spatial frequency. The output of the three chromatic mechanisms is combined according to a Minkowski metric (General Separable Model), or according to a Euclidean Distance measure (Ellipsoidal Separable Model). For all three observers the ellipsoidal model fits as well as the general separable model. Estimating the chromatic tuning improves the model fit for one observer.