Integration of information into a printed matter. Certification: Optical Multimedia Interface Lab, NAIST
A team from the Nara Institute of Science and Technology (NAIST), consisting of Ph.D. Student Arnaud Delmotte, Professor Yasuhiro Mukaigawa, Associate Professor Takuya Funatomi, Assistant Professor Hiroyuki Kubo, and Assistant Professor Kenichiro Tanaka have developed a new method for integrating information into a 3-D printed copy using a single printed item and documents. Information such as a serial identifier can be embedded without modifying the shape of the object and simply extracted from a single image of a commercially available document scanner.
There are many technologies for 3-D printing, but the most common method is to lay layers of molten plastic on top of each other. This method is known as FDM (Fused Deposition Modeling). In general, plastic deposition is carried out with layers of constant thickness. However, in the proposed method, pairs of vertically adjacent layers are selected and the thickness equilibrium is modified according to the information to be incorporated. This thickness balance modification has little effect on the outer shape of the object.
In addition, the thickness of the printed layers can be accurately measured by scanning the document scanner object. The sophisticated method allows for the detection of changes in layer thickness and the extraction of embedded information.
The results of this research were published in the international academic journal IEEE Multimedia Transactions (TMM) on 25 December 2019.
Background and purpose:
“Digital watermarking” is a technology that integrates information into digital content such as images, audio, video and 3-D models. Some methods, such as barcode and QR, integrate information visually. Other methods incorporate it secretly, with additional information hidden in the content and not perceived by the user. Since 2010, 3-D printing technology has been gaining popularity, resulting in increased interest in 3-D printed watermark technology. In this research, we propose a new method for incorporating a watermark when printing an object and focus our attention on minimizing distortion on the outer shape to prevent the object from being initialized.
Three-dimensional printed object (FDM) with embedded information using our method. Certification: Optical Multimedia Interface Lab, NAIST
Compare normal with our method. Left: regular printing. Right: print with modified layer thickness using our method. Principle: printed matter. Bottom: scanned image with document scanner. Certification: Optical Multimedia Interface Lab, NAIST
There are many technologies for 3-D printing. Among these, Combined Deposition Modeling (FDM) is the most common. It consists of laying layers of molten plastic on top of each other. The desired shape is achieved by precisely controlling the position and flow of a print nozzle so that the clay plastic layers have a controlled path and thickness. In general, the plastic flow is controlled to produce a constant layer thickness. However, in our method, the plastic flow is modified during printing to localize the thickness of the layer to incorporate some additional information. To avoid degradation of the outer surface of the object, pairs of vertically adjacent layers are selected and the proportion of their respective thicknesses is modified while maintaining the sum of the two layers of thickness. Since a typical layer thickness is about 0.2 mm, the information can be embedded in a relatively small area ranging from a few millimeters to a few centimeters.
To retrieve the embedded information, it is necessary to measure the thickness of the layers. However, our method can do this measurement using only one common document scanner and requires no special equipment. The FDM printing process naturally produces some layer artifacts that are visible in the images taken by a document scanner. These objects allow us to measure the thickness of the layers and extract the information.
This method can integrate various types of information, such as a URL that can be linked to Web services. a unique identifier that can be used to identify a product. and the printer ID and print date for managing the quality batch.
A new process could boost 200-percent 3-D prints
Arnaud Delmotte et al, Blind Watermarking for 3D printed objects with localized layer thickness modification, IEEE Multimedia Transactions (2019). DOI: 10.1109 / TMM.2019.2962306
Nara Institute of Science and Technology
A technology for integrating data into hardcopy (2020, January 16)
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