• Proceedings of the Safety Management and Science Conference
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• 2006.11a
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• pp.239-254
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• 2006

In mold structure machining, tool interference is a phenomenon which results from a collision between a blade of tool and a workpiece. Also tool collision is a phenomenon which results from a collision of holder with the object to be machined. These phenomena not only cause damages to mold and tool but also increase machining time and cost. To detect a collision of a tool to mold structure, first of all, the mold structure and a tool must be defined with famous geometric models such CSG, B-rep, and Voxel. A tool is defined as a combination of the blade, the shank, and the holder. This thesis reviews various collision detection algorithms using z-map and computer 3D graphic collision detection algorithms for the tool in machining a mold structure.

• Journal of Korea Multimedia Society
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• v.25 no.4
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• pp.559-567
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• 2022

The optimal shipping location is determined by measuring the volume and weights of cargo shipped to non-standard cargo carriers. Currently, workers manually measure cargo volume, but automate it to improve work inefficiency. In this paper, we proposed the method of a real-time volume calculation using LiDar sensor for automating cargo measurement of non-standard cargo. For this purpose, we utilized the statistical techniques for data preprocessing and volume calculation, also used Voxel Grid filter to light weighted of data which are appropriate in real-time calculation. We implemented the function of Normal vectors and Triangle Mesh to generate surfaces and Alpha Shapes algorithms to process 3D modeling.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.10
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• pp.116-122
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• 2016

This paper proposes a practical object shape reconstruction method using an underwater imaging sonar. In order to reconstruct the object shape, three methods are utilized. Firstly, the vertical field of view of imaging sonar is modified to narrow angle to reduce an uncertainty of estimated 3D position. The wide vertical field of view makes the incorrect estimation result about the 3D position of the underwater object. Secondly, simple noise filtering and range detection methods are designed to extract a distance from the sonar image. Lastly, a low pass filter is adopted to estimate a probability of voxel occupancy. To demonstrate the proposed methods, object shape reconstruction for three sample objects was performed in a basin and results are explained.

• The KIPS Transactions:PartA
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• v.9A no.1
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• pp.83-92
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• 2002

The segmentation of target objects from three dimensional volume images is an essential step for visualization and volume measurement. In this paper, we present a method to detect the surface of objects by improving the widely used levoy filtering for volume visualization. Using morphological operators we generate completely closed surfaces and selectively segment objects using the volume growing algorithm. The presented method was applied to 3-D artificial sphere images and angiocardiograms. We quantitatively compared this method with the conventional levoy filtering using artificial sphereimages, and the results showed that our method is better in the aspect of voxel errors. The results of visual comparison using angiocardiograms also showed that our method is more accurate. The presented method in this paper is very effective for segmentation of volume data because segmentation, visualization and measurement are frequently used together for 3-D image processing and they can be easily related in our method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.5
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• pp.447-455
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• 2014

In this paper, we consider a representative integral imaging method in glasses-free 3D image processing and propose a prioritized transmission scheme for guaranteeing a received video quality in error-prone environments. According to the correlation of pixels consisting of each voxel of integral image, we set the priority differently and apply the modulation level according to this priority value. That is to say, the corresponding pixels with small variance are set to a high priority and transmitted by using a low level modulation that is robust under transmission errors, but the corresponding pixels with greater variance are set to a lower priority and transmitted by using a high level modulation that has a high bit error rate but fast transmission rate. Result shows that the proposed scheme that applies the error-robust modulation level to the important image bit stream with the high priority improves the peak to sidelobe ratio (PSR) of the received 3D image, compared with a typical method that use the same modulation level without distinction of priorities.

• The Korean Journal of Pain
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• v.35 no.3
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• pp.250-260
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• 2022

Background: Cranial nerve ganglia, which are prone to viral infections and tumors, are located deep in the head, so their detailed anatomy is difficult to understand using conventional cadaver dissection. For locating the small ganglia in medical images, their sectional anatomy should be learned by medical students and doctors. The purpose of this study is to elucidate cranial ganglia anatomy using sectioned images and three-dimensional (3D) models of a cadaver. Methods: One thousand two hundred and forty-six sectioned images of a male cadaver were examined to identify the cranial nerve ganglia. Using the real color sectioned images, real color volume model having a voxel size of 0.4 × 0.4 × 0.4 mm was produced. Results: The sectioned images and 3D models can be downloaded for free from a webpage, anatomy.dongguk.ac.kr/ganglia. On the images and model, all the cranial nerve ganglia and their whole course were identified. In case of the facial nerve, the geniculate, pterygopalatine, and submandibular ganglia were clearly identified. In case of the glossopharyngeal nerve, the superior, inferior, and otic ganglia were found. Thanks to the high resolution and real color of the sectioned images and volume models, detailed observation of the ganglia was possible. Since the volume models can be cut both in orthogonal planes and oblique planes, advanced sectional anatomy of the ganglia can be explained concretely. Conclusions: The sectioned images and 3D models will be helpful resources for understanding cranial nerve ganglia anatomy, for performing related surgical procedures.

• Journal of Korea Multimedia Society
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• v.4 no.2
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• pp.108-115
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• 2001

In this paper we are attempted to quantitative classification of the three object color regions on a RGB image using of an improved ML(Maximum Likelihood) classification method. A RGB color image consists of three bands i.e., red, green and blue. Therefore it has a 3 dimensional structure in view of the spectral and spatial elements. The 3D structural yokels were projected in RGB cube wherefrom the ML method applied. Between the conventionally and easily usable Box classification and the statistical ML classification based on Bayesian decision theory, we compared and reviewed. Using the ML method we obtained a good segmentation result to classify positive cell nucleus, negative cell Nucleus and background un a immuno-histological breast carcinoma image. Hopefully it is available to diagnosis and prognosis for cancer patients.

• The KIPS Transactions:PartA
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• v.19A no.4
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• pp.169-174
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• 2012

We present an algorithm that computes a 3 dimensional Voronoi diagram for a protein molecule in this paper. The molecule is represented as a set of spheres with van der Waals radii. The Voronoi diagram is constructed in the 3D space by finding the voxels containing it. For the feasibility of the computation, we represent the molecule as a BVH (bounding volume hierarchy), and our system is accelerated by modern graphics hardware with CUDA programming support. Compared to single-core CPU implementations, experimental results show 323 times faster performance in the computation time, when the space is partitioned into $2^{24}$ voxels.

• International journal of advanced smart convergence
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• v.13 no.2
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• pp.119-129
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• 2024

We look at Web 3.0 business model canvas (BMC) of metaverse gaming platform, The Sandbox (TS). As results, the decentralized, blockchain-based platform, TS benefits its creators and players by providing true ownership, tradability of decentralized assets, and interoperability. First, in terms of the governance and ownership, The SAND functions a governance token allowing holders to participate in decision and SAND owners can vote themselves or delegate voting rights to other players of their choice. Second, in terms of decentralized assets and activities, TS offers three products as assets like Vox Edit as a 3D tool for voxel ASSETS, Marketplace as NFT market, and Game Maker as a visual scripting toolbox. The ASSETS made in Vox Edit, sold on the Marketplace, can be also utilized with Game Maker. Third, in terms of the network technology, in-game items are no longer be confined to a narrow ecosystem. The ASSETS on the InterPlanetary File System (IPFS) are not changed without the owner's permission. LAND and SAND are supported on Polygon, so that users interact with their tokens in a single place. Last, in terms of the token economics, users can acquire in-game assets, upload these assets to the marketplace, use for paying transaction fees, and use these as governance token for supporting the foundation.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2003.09a
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• pp.76-76
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• 2003

Purpose: To assess clinical proton MR spectroscopy (MRS) as a noninvasive method for evaluating tumor malignancy at 3T high field system. Methods: Using 3T MRI/MRS system, localized water-suppressed single-voxel technique in patients with brain tumors was employed to evaluate spectra with peaks of N-acetyl aspartate (NAA), choline-containing compounds (Cho), creatine/phosphocreatine (Cr) and lactate. On the basis of Cr, these peak areas were quantificated as a relative ratio. Results: The variation of metabolites measurements of the designated region in 10 normal volunteers was less than 10%. Normal ranges of NAA/Cr and Cho/Cr ratios were 1.67$\pm$018 and 1.16:1:0.15, respectively. NAA/Cr ratio of all tumor tissues was significantly lower than that of the normal tissues (P=0.005). Cho/Cr ratio of high-grade gliomas was significantly higher than that of low-grade gliomas (P= 0.001), Except 4 menigiomas, lactate signal was observed in all tumor cases. Conclusions: The present study demonstrated that the neuronal degradation or loss was observed in all tumor tissues. Higher grade of brain tumors was correlated with higher Cho/Cr ratio, indicating a significant dependence of Cho levels on malignancy of gliomas. This results suggest that clinical proton MR spectroscopy could be useful to predict tumor malignancy. Acknowledgement: This study was supported by a grant of the Mid and Long Term Nuclear R/D Plan Program, Ministry of Science and Technology, Republic of Korea.