• Journal of Biomedical Engineering Research
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• v.21 no.4
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• pp.433-439
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• 2000

Volume rendering is a powerful tool for visualizing sampled scalar values from 3D data without modeling geometric primitives to the data. The volume rendering can describe the surface-detail of a complex object. Owing to this characteristic. volume rendering has been used to visualize medical data. The size of volume data is usually too big to handle in real time. Recently, various volume rendering algorithms have been proposed in order to reduce the rendering time. However, most of the proposed algorithms are not proper for fast rendering of large non-coded volume data. In this paper, we propose a block-based fast volume rendering algorithm using a shear-warp factorization for non-coded volume data. The algorithm performs volume rendering by using the organ segmentation data as well as block-based 3D volume data, and increases the rendering speed for large non-coded volume data. The proposed algorithm is evaluated by rendering 3D X-ray CT body images and MR head images.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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• pp.229-232
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• 2005

In this paper, an image-based "approach-align -grasp" visual servo control design is proposed for the problem of object grasping, which is based on the binocular stand-alone system. The basic idea consists of considering a vision system as a specific sensor dedicated a task and included in a control servo loop, and we perform automatic grasping follows the classical approach of splitting the task into preparation and execution stages. During the execution stage, once the image-based control modeling is established, the control task can be performed automatically. The proposed visual servoing control scheme ensures the convergence of the image-features to desired trajectories by using the Jacobian matrix, which is proved by the Lyapunov stability theory. And we also stress the importance of projective invariant object/gripper alignment. The alignment between two solids in 3-D projective space can be represented with view-invariant, more precisely; it can be easily mapped into an image set-point without any knowledge about the camera parameters. The main feature of this method is that the accuracy associated with the task to be performed is not affected by discrepancies between the Euclidean setups at preparation and at task execution stages. Then according to the projective alignment, the set point can be computed. The robot gripper will move to the desired position with the image-based control law. In this paper we adopt a constant Jacobian online. Such method describe herein integrate vision system, robotics and automatic control to achieve its goal, it overcomes disadvantages of discrepancies between the different Euclidean setups and proposes control law in binocular-stand vision case. The experimental simulation shows that such image-based approach is effective in performing the precise alignment between the robot end-effector and the object.

• The Journal of the Korea Contents Association
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• v.21 no.1
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• pp.147-161
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• 2021

Through photogrammetry techniques, what current researches can achieve at present is rough 3D mesh and color map of objects, rather than usable photo-realistic 3D assets. This research aims to propose a new method to create photo-realistic 3D assets that can be used in the field of visualization applications. The new method combines photogrammetry with computer graphics modeling. Through the description of the production process of three objects in the real world - "Bullet Box", "Gun" and "Metal Beverage Bottle," it introduces in details the concept, functions, operating skills and software packages used in the steps including the photograph object, white balance, reconstruction, cleanup reconstruction, retopology, UV unwrapping, projection, texture baking, De-Lighting and Create Material Maps. In order to increase the flexibility of the method, alternatives to the software packages are also recommended for each step. In this research, 3D assets are produced that are accurate in shape, correct in color, easy to render and can be physically interacted with dynamic lighting in texture. The new method can obtain more realistic visual effects at a faster speed. It does not require large-scale teams, expensive equipment and software packages, therefore it is suitable for small studios and independent artists and educational institutions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.4
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• pp.129-137
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• 2016

BIM libraries for architectural projects have been developed and distributed. However, they do not define physical and logical quality control methods for individual library objects, so there are some difficulties in securing reliability of 3D library models converted from 2D drawings. Because the BIM library contents can be built by participating material and member-fabrication companies, after making individual BIM library objects, a certification process through separate quality verification is very important when delivering as-built BIM libraries. Since the BIM library should have generality for usage, it is necessary to secure the quality of BIM library objects according to consistent verification standards. Therefore, this study suggests a quality verification method for certifying a BIM library object from physical and data perspectives by comparing existing 2D drawings in the BIM libraries built based on standardized 2D drawings from MOLIT. This method could be widely used for quality verification in delivering BIM libraries by companies in the construction sector and operated with rule set data for quality verification of as-built BIM models.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.3
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• pp.707-714
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• 2015

The national government is pushing hard the adoption of the BIM (Building Information Modeling) technology in the construction industry. The BIM application provides a visualized environment where the construction manager can inspect the structure of buidling structures. The application also provides information on activity progresses as well as earned values. However, BIM is mostly applied to visualize a structural object with definite forms. The BIM technology needs to be extended to include an object with non-definite forms such as earthwork operations. The objective of this study is to present a prototype of earthwork BIM in the construction operation. The prototype has been built on the attributes of geological information, construction equipment and positioning. The prototype of earthwork BIM shows a 3D graphic simulation of construction equipment moving around for digging and loading.

• Journal of Korea Game Society
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• v.7 no.4
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• pp.53-62
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• 2007

Although radiosity can represent diffuse reflections of the object surfaces by modeling energy exchange in 3D space, there are some restrictions for real-time applications because of its computation loads. Therefore, GPU(Graphics Processing Unit) based radiosity algorithms have been presented actively to improve its rendering performance. We implement the progressive refinement radiosity on GPU by G. Coombe in 3D scene that is constructed with HDR(High Dynamic Range) radiance map. This radiosity method can generate a photo-realistic rendering image in 3D space, where the synthetic objects were illuminated by the environmental light sources. In the simulation results, the rendering performance is analyzed according to the resolution of the texel in the environmental map and mipmaping. In addition, we compare the rendering results by our method with those by the incremental radiosity.

• Journal of the Korean Institute of Intelligent Systems
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• v.25 no.1
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• pp.78-84
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• 2015

Depth estimation is often required for robot vision, 3D modeling, and motion control. Previous method is based on the focus measures which are calculated for a series of image by a single camera at different distance between and object. This method, however, has disadvantage of taking a long time for calculating the focus measure since the mask operation is performed for every pixel in the image. In this paper, we estimates the depth by using the focus measure of the boundary pixels located between the objects in order to minimize the depth estimate time. To detect the boundary of an object consisting of a straight line and a circle, we use the Hough transform and estimate the depth by using the focus measure. We performed various experiments for PCB images and obtained more effective depth estimation results than previous ones.

• Proceedings of the CALSEC Conference
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• 1999.07a
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• pp.215-231
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• 1999

CALS, Enterprise Integration, Virtual Enterprise 등을 구현하는데 있어서 BPR (business process re-engineering), ISP (Information Strategy Planning), Analysis/Design 등은 필수 적이다. 이러한 BPR, ISP, A/D 추진하는데 있어서 각 단계의 산출물은 유연하게 연계되지 못한다. 그 이유는 각 단계가 접근하는 초점이 다르고, 산출물의 성격이 다르며, 무엇보다도 각 단계의 전문가가 다르기 때문에 발생한다. 현재 기업이 각 단계를 추진할 때에는 반복적인 피드백을 통하여 정보를 공유하거나, 각 단계의 정보 연계가 제대로 이루어지지 않는다. 이러한 문제를 해결하기 위하여 BPR-ISP-A/D의 정보 연계를 유연하게 하기 위하여 PPO (Product-Process-Organization) 객체 진화에 의한 통합 방법론을 제안 하고자 한다. 그 과정은 1) Real world 정보를 PPO 객체로 정의하고, 2) PPO 객체를 기반으로 BPR을 수행하여 TO-BE model 을 만드는 동시에, 3) PPO TO-BE model과 함께 IT Architecture를 정의하며, 4) PPO 객체를 기반으로 Analysis and Design 과정을 통하여 Application system 객체 및 Data 객체를 정의한다. 이때 PPO 객체는 Real-world 객체에서 Application system 객체 및 Data 객체로 진화하게 되고 BPR-ISP-A/D의 seamless 통합이 이루어진다. 여기서, 단계 1) 과 2)는 System Engineering을 통하여 이루어진다. ARIS(Architecture of Integrated Information System, Dr. A-W. Scheer, 1998)개념을 도입하여 실세계를 정해진 규약에 따라 Model로 Mapping하고, 생성된 Model을 바탕으로 BPR을 수행하여 개선된 Model을 산출해 낸다. 단계 3)은, IE (Information Engineering, James Martine, 1990) 의 ISP가 도입되어, 설계업무를 지원하기위한 기본적인 시스템 구조를 구상하게 된다. 이와 함께 IT Model을 구성하게 되는데, 객체지향적 접근 방법으로 Model을 생성하고 UML(Unified Modeling Language)을 Tool로 사용한다. 단계 4)는 Software Engineering 관점으로 접근한다. 이는 최종산물이라고 볼 수 있는 설계업무 지원 시스템을 Design하는 과정으로, 시스템에 사용될 데이터를 Design하는 과정과, 데이터를 기반으로 한 기능을 Design하는 과정으로 나눈다. 이를 통해 생성된 Model에 따라 최종적으로 Coding을 통하여 실제 시스템을 구축하게 된다.

• Journal of KIBIM
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• v.10 no.4
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• pp.32-39
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• 2020

In recent years, the construction industry is getting bigger and more complex, so it is becoming difficult to acquire point cloud data for construction equipments and workers. Point cloud data is measured using a drone and MMS(Mobile Mapping System), and the collected point cloud data is used to create a 3D digital map. In particular, the construction site is located at outdoors and there are many irregular terrains, making it difficult to collect point cloud data. For these reasons, adopting a noise reduction algorithm suitable for the characteristics of the construction industry can affect the improvement of the analysis accuracy of digital maps. This is related to various environments and variables of the construction site. Therefore, this study reviewed and analyzed the existing research and techniques on the noise reduction algorithm. And based on the results of literature review, performance evaluation of major noise reduction algorithms was conducted for digital maps of construction sites. As a result of the performance evaluation in this study, the voxel grid algorithm showed relatively less execution time than the statistical outlier removal algorithm. In addition, analysis results in slope, space, and earth walls of the construction site digital map showed that the voxel grid algorithm was relatively superior to the statistical outlier removal algorithm and that the noise removal performance of voxel grid algorithm was superior and the object preservation ability was also superior. In the future, based on the results reviewed through the performance evaluation of the noise reduction algorithm of this study, we will develop a noise reduction algorithm for 3D point cloud data that reflects the characteristics of the construction site.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.6
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• pp.567-576
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• 2017

The object of this research is an establishment of BIM-based quantity takeoff(QTO) and cost estimation guidelines for reinforcement concrete structures focused on improvement of field applicability in transition period from 2D drawing-based environment to 3D BIM-based environment. Preliminary studies on existing guidelines and standards for BIM modeling, QTO and cost estimation of reinforcement concrete structures are performed, and then a standardization of BIM-based cost estimation process is proposed through comparative analysis between 2D drawing-based cost estimation process and 3D BIM-based. In addition, modeling, QTO, and cost estimation processes of cost-BIM model for RC structures are conducted. The contributions of this research and the guidelines suggested by this research are 1) lowering barriers to entity to the new BIM-based environment for small size companies, 2) reducing construction cost by a close estimate, 3) establishing the foundation for integrated management of informations through construction project life cycle, 4) and ultimately, developing the BIM ecosystems.