Approach are secretly recorded and can be utilized inside the authentication processes. These information are listed in Table 1. The first item will be the Watermark image taken inside the encoding stage. It is actually referred to as the recorded watermark hereafter. This signal will likely be made use of to verify digital models, G-code programs, and printed components. The second and third Platensimycin medchemexpress Products will be the disturbance worth along with the ROI. This info aids us to find and capture watermarks in digital and physical models. The final recorded parameter is the view angle in which we generate the recorded watermark.Table 1. Recorded watermarking information. Information Products Watermark Disturbance Region of interest (ROI) View angleType 2D image Real number Oriented bounding box (OBB) Directional vectorUsage Verification Watermark capturing Watermark browsing Watermark retrievala 32 32 binary image.Appl. Sci. 2021, 11,7 ofBesides keeping these data, a physical model may be manufactured as well. This printed object includes the watermark and can serve as the regular model for verifying printed components within the future. 2.six. Watermark Detection Procedures Given that watermarks may be embedded into digital models, G-code programs, and physical parts, different decoding techniques are derived to manage these contents accordingly. Their flowcharts are illustrated in Figure five. The procedures for verifying G-code applications and digital models are equivalent. They depend on virtual manufacturing, volume rendering, and similarity evaluation to attain their goals. On the other hand, the authentication Appl. Sci. 2021, 11, x FOR PEER Evaluation 8 of 16 process for physical components invokes physical manufacturing, image capturing, and visual comparison. These 3 watermark detection algorithms are described in this subsection.Figure 5. Watermark verification methods for (a) digital model models and G-codes, (b) physical Figure 5. Watermark verification methods for (a) digital model models and G-codes, (b) physical parts. parts.The technique committed to authenticating a G-code program is shown in portion (a) of three. Experimental Outcomes Figure 5. Initially, the G-code program is emulated by utilizing a simulator to generate Primarily based around the proposed embedding and detecting schemes, we built a watermarking a voxel model. The design, implementation, and functionalities of this simulator are system aiming to enhance the security of AM. The major elements of this method inpresented in [27]. Then, the model is volume-rendered to search for a trace of watermark. clude an encoder plus a decoder. The former is responsible for embedding watermarks, If a watermark seems in the resultant pictures, we extract the watermark by using the even though the latter is utilized to In the contents. step, the similarity between this watermark recorded view angle and ROI. verify following In addition to these two applications, the slicer and simulator, developed within the researches of [26] dHash are also employed to translate along with the recorded one particular is computed by utilizing theand [27],technique of [28]. If the resultant voxel value is higher than a predefined threshold, we assume that this G-code is models, dHashmodels into G-code programs and to convert G-code programs into voxelgenuine. respectively. Many experiments we volume-render this model to confirm the existence To examine a digital model, had been developed and performed to test the system. Some of the test Then, are watermark is analyzed in making use of the recorded ROI and view of a watermark. resultsthis presented andretrieved by this section. parameter.
