We proposed the method for non-destructively embedding information inside a 3D fabricated object very clearly by the process of re-magnetization. Our strong points are that the 3D object is finished (ready to use) after only a printing process, and is able to be reused by re-writing information many times. In this paper, we investigated the effects of the depth (positions inside the object) of the storage cell, which is printed as a ferromagnetic filament, on the clarity of the embedded information. Our purpose: we need to find the conditions that gave the most benefit in both obtaining high magnetic strength and protecting the embedded information. With this advantage, the method leads to the production of creating the high-quality household 4D object, the personal interactive 3D object, in the near future.
The frieze of the Palace of the stuccoes, dated between the 5 th and 6 th century BC, was a polychrome Maya relief discovered in the 1907 in Yucatán, Mexico. It was documented in watercolours and hand tinted photographs by Adela Breton. After years of exposure to the harsh environmental conditions of the Maya area, the colours and the stucco relief disappeared. The aim of the project is to develop a hybrid digital-analogue printing method for reconstructing the appearance of the original polychrome relief based on digitised hand-made records.<br/> A description of the process to produce full colour images combining digital and photomechanical printing is provided. Using photopolymer plates, an intaglio printing process has been used to produce colour images, whilst inverse relief plates have been created based on height maps to transfer a positive embossing on paper when applying pressure on a printing press. The influence of physical parameters related to the appearance is studied. Reflectance Transformation Imaging was carried out to record the colour and surface shape of the prints. Measurements of gloss were made on relief inkjet prints and intaglio prints on paper to compare the outcomes of commercial 2.5D print and the method proposed here.<br/> By modifying an analogue process with digital technology, it is possible to incorporate ancient materials to the printmaking process and therefore approach naturally the appearance of the original. On the other hand, incorporating imaging techniques and quality measurements enables to improve the quality in analogue printing techniques.
Digital multi-toning is a technique for converting a continuous-tone image into a multi-tone image for its reproduction with a multi-tone output device. It is becoming important as printers now have the ability to print dots of different intensities. Error Diffusion (ED) is an algorithm that has been shown to be effective for the multi-toning process and has been widely applied to digital printing tasks. However, in the actual printing process, conventional ED techniques for digital multi-toning are often unable to print a sufficiently good-quality image because of physical or mechanical dot gain. In particular, distortion of the contour of printed letters is noticeable. Black letters against a white background appear enlarged, whereas white letters on a black background appear faded. In this paper, we propose an edge-preserving ED algorithm to improve the quality of printed images. We prepare different quantization thresholds between the edge and other regions to allow for stable detection of the edge regions. In addition, we propose a multi-step edge-detection algorithm to avoid printed artefacts. Experimental results using printed images showed that the proposed algorithm improved the quality of printed images in comparison with conventional techniques.
The traditional diagnostics of print quality requires to print a professionally designed test-page and visually evaluated by an expert, which is very costly and time-consuming. Instead, a system that could automatically diagnose a customer's printer without any human's interference is proposed in this paper. The system relies on scanning user's printed output from user's printer. Print defects such as banding, streaking, etc. will be reflected on its scanned page and can be captured by comparing to its master image. The master image is the digitally generated original from which the page is printed. Once the print quality drops below a specified acceptance criteria level, the system can notify the user of the presence of print quality issues.. The current process has only concentrated on one type of print defect: text fading. The scanned page will initially be aligned with its master image with a feature based image registration algorithm. Text regions of the two pages are then extracted and compared directly.
2.5D printing is a technology which creates surface relief by superimposing successive layers of inks. The question of the characterization of heights obtained with this technique brings us to consider new metrics and mathematical ways to represent the influence of diverse printing parameters on the obtained relief, possibly used to compensate the defaults of the system. Our method takes over the classical Modulation Transfer Function (MTF) approach and adapts it to a vertical modulation instead of considering the (x, y) plane, introducing then a Height Modulation Transfer Function (HMTF). Characterization charts are composed of lines patterns printed at different heights, frequencies and droplet levels. Prints are scanned with a chromatic confocal sensor and resulting topographies are analyzed to extract the HMTF. By analogy with traditional MTF methods, results – consisting of the measurement of the deviation between the digital input and the analog output – allow to evaluate the quality of our printer and to compensate it by setting up a retro-action loop. The method, here presented in the case of the 2.5D printing prototype, can be extended to regular 3D printing techniques.