Youichi Takashima

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.

New Technique for Embedding Depth Information in Captured Images Using Light Beam Containing Invisible High-Frequency Patterns—Design and Preparation of New Experimental Setup With Some Comments

This paper proposes the method and system to invisibly embed the depth data of a target object into the image captured with a camera at the same timing as taking its shot. The proposed system consists of a projector to throw the illumination light wherein the invisible periodical pattern has been contained, and a camera to take a shot of target object. The projector and camera were aligned so that these devices could be positioned in different depths along the z-coordinate. This kind of alignment enables us to set the spatial frequency of the invisible periodical pattern superimposed onto the image of target object taken with the camera, changeable depending on the depth of the target object. This kind of spatial frequency determined depending on the depth of the object allow us to estimate the depth of target object taken with the camera, based on the spatial frequency of the periodical pattern being taken with the camera at the same time. Based on the fundamental study described above, since this paper allows us to estimate the spatial frequency of the periodical pattern contained in the image being taken with the camera, we are enabled to simultaneously generate the depth map of the 2D image being captured. A 3D image could thus be constituted with the captured 2D image combined with the depth map generated. The proposed new techniques, employing a traditional -D image format without any modification, are advantageous in easiness of transferring and storing the 3D images over the conventional 3D image generations.

Design considerations for new 3D image display system with improved compatibility with invisibility and readability.

This paper describes design considerations for acquiring improved performance on a new type of display system for regenerating three-dimensional images with an invisible high-frequency code pattern whose attribute depends on the depth of object. Three-dimensional images to be demonstrated on the new 3D image display system will be generated in the following 3 steps: That is; firstly embedding data of depth information into a 2D object image while taking it with a camera, secondly estimating true value of depth information embedded, and thirdly eliminating invisible pattern from an object image taken or diminishing contrast ratio depending on an estimated value of image depth. Here, we have to note that the diminished contrast implies reduced readability on an object image. With these three steps, improved compatibility with invisibility and readability on an invisible pattern was set up at optimum with an allowable margin.

Information Hiding Inside 3-D Printed Objects by Forming High Reflectance Projections

This paper proposes a technique that can embed information invisibly inside 3-D printed objects by forming projections with high reflectance characteristics for near infrared light inside the outer shell of an object. The information is expressed by an arrangement of projections. Polylactic resin is used as the material. This paper also presents a technique that can nondestructively read out information from inside real objects using a reflectance image of the object captured with near infrared light and a camera. We conducted experiments to evaluate the feasibility of this technique by using a light source that emitted light whose peak wavelength was 1,550 nm and an InGaAs near infrared camera that had sensitivity in a range from 700 to 1,900 nm. We could see projections in captured images with sizes over 2 mm and these results demonstrated that the embedded information could accurately be read out, which confirmed the feasibility of the technique we propose in this paper.

Improving compatibility with invisibility and readability for new 3D image display system

This paper describes established new 3D display systems for completely satisfying the invisibility and readability at the same time in a code pattern to measure the depth map. Three-dimensional images to be demonstrated on the new 3D image display system will be generated on the blue channel with a help of the red channel in the following 3 steps. Firstly, high invisibility has been attained by changing colored projection pattern using the checkerboard pattern in the blue channel to enhance the invisibility toward human eyes characteristics. Secondly, higher contrast is kept unchanged to enhance readability more than ever. Thirdly, the pattern noise caused by the checkerboard pattern on the blue channel was eliminated, in support of red channel, by estimating the value of spatial frequency response on the blue channel, based on the spatial frequency response on the red channel, provided no pattern noise occurred, and also provided that the blue, green, and red channels are projected from a single projector. According to the three steps, invisibility and readability were drastically improved, on the enhanced readability with fewer pattern noise to an invisible level.