Piyarat Silapasuphakornwong

Copyright Protection for 3D Printing by Embedding Information Inside Real Fabricated Objects

This paper proposes a technique that can protect the copyrights of digital content for 3D printers. It embeds the information on copyrights inside real objects fabricated with 3D printers by forming a fine structure inside the objects as a watermark. Information on copyrights is included in the content before data are input into the 3D printer. This paper also presents a technique that can non-destructively read out information from inside real objects by using thermography. We conducted experiments where we structured fine cavities inside the objects by disposition, which expressed binary code depending on whether or not the code was at a designated position. The results obtained from the experiments demonstrated that binary code could be read out successfully when we used micro-cavities with a horizontal size of 2 x 2 mm, and character information using ASCCI code could be embedded and read out correctly. These results demonstrated the feasibility of the technique we propose.

Non-destructively reading out information embedded inside real objects by using far-infrared light

This paper presents a technique that can non-destructively read out information embedded inside real objects by using far-infrared-light. We propose a technique that can protect the copyrights of digital content for homemade products using digital fabrication technologies such as those used in 3D printers. It embeds information on copyrights inside real objects produced by 3D printers by forming fine structures inside the objects as a watermark that cannot be observed from the outside. Fine structures are formed near the surface inside real objects when they are being fabricated. Information embedded inside real objects needs to be read out non-destructively. We used a technique that could non-destructively read out information from inside real objects by using far-infrared light. We conducted experiments where we structured fine cavities inside objects. The disposition of the fine domain contained valuable information. We used the flat and curved surfaces of the objects to identify them. The results obtained from the experiments demonstrated that the disposition patterns of the fine structures appeared on the surface of objects as a temperature profile when far-infrared light was irradiated on their surface. Embedded information could be read out successfully by analyzing the temperature profile images of the surface of the objects that were captured with thermography and these results demonstrated the feasibility of the technique we propose.

Copyright Protection for 3D Printing by Embedding Information Inside 3D-Printed Objects

This paper proposes a technique that can protect the copyrights of digital content for 3D printers. It embeds the copyright information inside 3D-printed objects by forming a fine structure inside the objects as a watermark. Information on copyrights is included in the digital data for a real object before data are input into the 3D printer. This paper also presents a technique that can non-destructively read out information from inside real objects from a transparent image of the object using near infrared light. We conducted experiments using polylactide resin where we structured fine domains inside the objects. The domains have higher density than other regions. The disposition of the fine domains expressed binary code depending on whether or not they were at a designated position. The results obtained from the experiments demonstrated that the image of the fine domain inside the object can be captured by the near infrared camera and binary code could be read out successfully. These results demonstrated the feasibility of our technique showing that enough information can be embedded for copyright protection.

Nondestructive Readout of Copyright Information Embedded in Objects Fabricated with 3-D Printers

We studied a technique to protect the copyrights of digital data for 3-D printers to prevent illegal products from being fabricated with 3-D printers, which has become a serious economic problem. We previously proposed a technique that could be used to check whether illegal acts had been committed by embedding copyright information inside real objects fabricated with 3-D printers by forming fine cavities inside them and nondestructively reading the information out. We demonstrated that the proposed technique was feasible in practice. We examined a new method of nondestructive readout in this study by using thermographic movie files where the binary images of individual frames were summarized to amplify the signals of the cavity patterns and demonstrated the feasibility of automatic readout with 100 % accuracy in reading out embedded information.

Information embedding in real object images using temporally brightness-modulated light

We propose a new technology that can be used to invisibly embed information into the images of real objects that are captured with a video camera. This technique uses illumination that invisibly contains certain information. Because the illumination on a real object contains information, an image of the object taken with a video camera also contains information although it cannot be seen in the captured image. This information can be extracted by image processing. It uses temporally luminance modulated patterns as invisible information. The amplitude of the modulation is too small to perceive. The frequency of modulation is the same as the frame frequency of the projector that is used as a lighting device. The frame images over a certain period are added up after the sign of the even- or odd-numbered frames is changed. Changes in brightness by modulation in each frame are accumulated over the frames. However, the object and background image are removed because the even and odd frames are opposite in sign. As a result, the patterns become visible. We conducted experiments and the results from these revealed that invisible patterns could be read out. Moreover, we evaluated the invisibility of the embedded patterns and confirmed that conditions existed where both the invisibility and readability of the patterns were simultaneously satisfied.