• Journal of Institute of Control, Robotics and Systems
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• v.8 no.2
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• pp.151-157
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• 2002

A 3-dimenstional automatic solder paste inspection system is described that can be used to find defects occurring in solder paste printing process. This system extracts height and volume information very fast as well as area of solder paste printed, using multiple slit ray projection and Galvano-mirror scanning. Methods are presented on calibration of camera and slit projector, real-time image processing of multiple slit images, determination of reference height, and extraction of paste height information are proposed. Performance of the system was successfully demonstrated through field tests.

• International Journal of Internet, Broadcasting and Communication
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• v.11 no.4
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• pp.49-58
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• 2019

3D scanners are needed in various fields, and their usage range is greatly expanded. In particular, it is being used to reduce costs at various stages during product development and production. Now, the importance of quality inspection in the manufacturing industry is increasing. Structured optical system applied in this study is suitable for measuring high precision of mold, press work, precision products, etc. and economical and effective 3D scanning system for measuring inspection in manufacturing industry can be implemented. We developed Structured light 3D scanner which can measure high precision by using Digital Light Processing (DLP) projector and camera. In this paper, 3D image scanner based on structured optical system can realize 3D scanning system economically and effectively when measuring inspection in the manufacturing industry.

• Journal of Internet Computing and Services
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• v.11 no.5
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• pp.27-35
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• 2010

In this paper, we propose a method that can compensate the geometric distortions of image caused from an arbitrary nonflat display surface(or wall) under the environment of portable overhead projector without a flat screen. In the proposed method, we first project a grid pattern to an arbitrary nonflat display surface and then derive an equation of straight line that represents the geometry relationship between the distorted grid pattern and the original grid pattern. Next, after determining the proper size of the original grid pattern according to the form of the display surface, we generate a compensation pattern from the derived equation of straight line, which can symmetrically compensate for the distorted image. Finally, we compensate for the geometric distortions of the projected image by segmenting the real image to be projected from portable overhead projector and prewarping it according to the compensation pattern. To evaluate the proposed method, we performed experiments of image compensation on inclined surface, bent surface and curved surface that are frequently occurred in the environment of portable overhead projector without a flat screen. From the experimental results, we found that the proposed method could be very effective in compensating for the general types of the geometric distortions of the projected images.

• Journal of the Korea Society of Computer and Information
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• v.16 no.9
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• pp.97-105
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• 2011

This paper proposes a new "Live Book Service" that is combined the analog contents such as paper books and digital contents with various digital multimedia elements, and this service can project the additional digital multimedia contents on the analog paper. Also, we developed a monolithic stand type system which is composed of camera and pico projector, so that it can demonstrate the proposed contents. We also devised the low computational cost algorithm in bare-hands recognition which can be used as the interface between the system and users. In addition, to recognize the bare-hands which can be used as the interface between the digital and users, we make the low cost algorithm. Therefore this can be the interaction between the system and users. As a result, our proposed system can be used as a useful tool for various e-book or u-learning fields that requires high efficiency and much immersion.

• Korean Journal of Computational Design and Engineering
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• v.18 no.4
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• pp.283-289
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• 2013

Presented in this paper is an adaptive measuring procedure of dental impression using the Structured Light System. While measuring a complex object, such as dental impression, in the reverse engineering, it is not possible to acquire all parts of the scanned surface. Missing scanned data is resulted in holes in a created triangular mesh. The focus of this paper is to introduce an algorithm for automatic identification of additional scanning orientations to fill holes that are created by a default scan. The proposed algorithm was developed by the three major technological requirements: camera visibility, projector visibility, data reliability. In order to satisfy the requirements, the proposed algorithm determines additional scanning orientation from the orientation of a projection plane derived from the average normal vector of boundary triangles.

• Journal of Biomedical Engineering Research
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• v.28 no.6
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• pp.786-790
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• 2007

Up to now, surgeons have operated while peering at images which visualize the medical state of the patient such as MRI or CT images. On the other hand, direct-projected augmented reality technology liberates surgeons from the inconvenience by directly projecting medical information onto the patient's body. However surgeons still feel inconvenient when they mark surgical targets for planning an operation because they use an ink pen which is difficult to modify or delete and is also likely to be unsanitary. In this paper, we resolve these problems by proposing an interactive user interface based on direct-projected augmented reality technology and its validity is shown in experimental results.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04c
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• pp.594-596
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• 2003

지금까지 구현된 대부분의 가상환경 시스템은 헤드마운트디스플레이(HMD), 트랙커, 핸드 글로브, 포스 피트백 센서등의 전문적인 장비를 이용하여 구현되었으며 인터액티브한 장면을 연출하기 위하여 고속의 하드웨어 사양을 필요로 하였다. 현재 이러한 장비는 전문가가 아니면 사용하기가 어렵고 또 장비의 비용이 매우 고가이기 때문에 대중화되기까지 상당한 시간이 소요될 것으로 예상된다. 본 논문은 이와 같은 전문적인 장비가 아닌 범용장비에 속하는 CCD 카메라와 빔 프로젝트를 활용하여 사용자가 인터액티브하게 참여할 수 있는 게임 시스템의 설계와 구현에 관한 논문이다. 이 시스템에서 사용자는 별도의 센스가 부착된 장비가 없이 간단한 색상 마커만을 가지고 컴퓨터가 생성한 가상 공간에서 빔 프로젝트로 구성한 가상 공간에서 캐릭터와의 실시간 게임을 즐길 수 있는 기능을 가지고 있다.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.2
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• pp.116-124
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• 2011

A service robot can identify its own position relative to landmarks, the locations of which are known in advance. The main contribution of this research is that it gives various ways of making the self-localizing error smaller by referring to special landmarks which are developed as high gain reflection material and coded array associations. In this paper, the authors propose a set of indices to evaluate the accuracy of self-localizing methods using the selective reflection landmark and infrared projector, and the indices are derived from the sensitivity enhancement using 3D distortion calibration of camera. And then, the accurarcy of self-localizing a mobile robot with landmarks based on the indices is evaluated, and a rational way to minimize to reduce the computational cost of selecting the best self-localizing method. The simulation results show a high accuracy and a good performance.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.428-432
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• 1988

In this study, some issues on 3- dimentional object recognition and pose determination are discussed. The method employs a laser projector which projects a cyliderical light beam on the object plane where it produces a bright ring pattern. The picture is then taken by a T.V camera. The ring pattern is mathmetically the ellipse of which the geometrical parameters have the 3-dimentional feature of the object plane. This paper gives the mathematical aspects of 3-dimentional recognition method and shows experimentally the variations of ellipse parameters as the spatial deviation of the plane object.

• JSTS:Journal of Semiconductor Technology and Science
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• v.12 no.2
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• pp.193-202
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• 2012

In this paper, we propose a new approach for compact range sensor system for real-time robot applications. Instead of using off-the-shelf camera and projector, we devise a compact system with a CMOS image-sensor and a DMD (Digital Micro-mirror Device) that yields smaller dimension ($168{\times}50{\times}60mm$) and lighter weight (500g). We also realize one chip hard-wired processing of projection of structured-light and computing the range by exploiting correspondences between CMOS images-ensor and DMD. This application-specific chip processing is implemented on an FPGA in real-time. Our range acquisition system performs 30 times faster than the same implementation in software. We also devise an efficient methodology to identify a proper light intensity to enhance the quality of range sensor and minimize the decoding error. Our experimental results show that the total-error is reduced by 16% compared to the average case.