• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.9
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• pp.2341-2348
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• 1996

This paper proposes an image compression algorithm that adopts projection scheme on mean-residual metod. Sub-blocks of an image are encoded using mean-residual method where mean value is predicted according to that of neighboring blocks. Projection scheme with 8 directions is applied to the compression of residual signals of blocks. Projection vectors are finite-state vector quantized according to the projection angle of nighboring blocks in order to exploit the correlation among them. Side information to represent the repetition of projection is run-length coded while the information for projection direction is compressed using entropy encoding. The proposed scheme apears to be better in PSNR performance when compared with conventional projection scheme as well as in subjective quality preserving the edges of images better than most tranform methods which usually require heavy computation load.

• Advances in robotics research
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• v.2 no.1
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• pp.45-57
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• 2018

Even though the popularity of projection mapping continues to increase and it is being implemented in more and more settings, most current projection mapping systems are limited to special purposes, such as outdoor events, live theater and musical performances. This lack of versatility arises from the large number of projectors needed and their proper calibration. Furthermore, we cannot change the positions and poses of projectors, or their projection targets, after the projectors have been calibrated. To overcome these problems, we propose a projection mapping method using a projector robot that can perform projection mapping in more general or ubiquitous situations, such as shopping malls. We can estimate a projector's position and pose with the robot's self-localization sensors, but the accuracy of this approach remains inadequate for projection mapping. Consequently, the proposed method solves this problem by combining self-localization by robot sensors with position and pose estimation of projection targets based on a 3D model. We first obtain the projection target's 3D model and then use it to accurately estimate the target's position and pose and thus achieve accurate projection mapping with a projector robot. In addition, our proposed method performs accurate projection mapping even after a projection target has been moved, which often occur in shopping malls. In this paper, we employ Ubiquitous Display (UD), which we are researching as a projector robot, to experimentally evaluate the effectiveness of the proposed method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.9B
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• pp.1785-1794
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• 1999

The affine projection algorithm has known t require less computational complexity than RLS but have much faster convergence than NLMS for speech-like input signals. But the affine projection algorithm is still much more computationally demanding than the LMS algorithm because it requires the matrix inversion. In this paper, we show that the affine projection algorithm can be realized with the Gram-Schmidt orthogonalizaion of input vectors. Using the derived relation, we propose an approximate but much more efficient implementation of the affine projection algorithm. Simulation results show that the proposed algorithm has the convergence speed that is comparable to the affine projection algorithm with only a slight extra calculation complexity beyond that of NLMS.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.30B no.5
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• pp.90-102
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• 1993

In this paper, we propose a prgressive image transmission technique using hierarchical pyramid data structure which is constructed based on the projection data of an image. To construct hierarchical Gaussian pyramids, we first divide an image into 4$\times$4 subblocks and generate the projection data of each block along the horizontal, vertical, diagonal, and antidiagonal directions. Among images reconstructed by backprojecting the projection data along a single direction, the one giving the minimum distortion is selected. The Gaussian pyramid is recursively generated by the proposed algorithm and the proposed Gaussian images are shown to preserve edge information well. Also, based on the projection concept a new transmission scheme of the lowest Laplacian plane is presented. Computer simulation shows that the quantitative performance of the proposed pyramid coding technique using projection concept is similar to those of the conventional methods with transmission rate reduced by 0.1 ~ 0.2 bpp and its subjective performance is shown to be better due to the edge preserving property of a projection operation.

• Proceedings of the Korean Society of Computer Information Conference
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• 2015.07a
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• pp.264-267
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• 2015

본 논문에서는 개선된 고속의 Back Projection 기법과 에지맵 보간을 이용한 단일영상 기반의 초해상도(super resolution) 영상을 생성하는 알고리즘을 제안한다. 본 논문에서 제안하는 알고리즘은 영상의 색채 왜곡을 방지하기 위해 RGB 컬러 도메인에서 HSV 컬러 도메인으로 변경하여 밝기정보인 V만 이용한다. 먼저 잡음제거와 속도 향상을 위해 개선된 고속 back projection을 이용해 영상을 확대 재구성한다. 이와 함께 LoG(laplacian of gaussian) 필터링을 이용하여 에지 맵을 추출한다. 에지의 정보와 back projection의 결과를 이용하여 고해상도 영상을 재구성한다. 제안하는 알고리즘을 이용하여 복원한 영상은 부자연스러운 인공물을 효과적으로 제거하고, blur현상을 줄여 에지 정보를 보정하고 강조해준다. 또한 실험을 통해 제안하는 알고리즘이 기존의 보간법과 전통적인 back projection 결과보다 주관적인 화질이 우수하고 객관적으로 우수한 성능을 나타내는 것을 입증한다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.31 no.3
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• pp.183-192
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• 2013

As a worldwide trend, the spatial information that is established by country, institution and purpose is integrated into the data with a single spatial reference to improve the data connectivity and usability. In this study, a new national single origin plane rectangular coordinate system was studied to efficiently respond to the changes in the spatial reference according to the introduction of a new national geodetic standard and to the demand of seamless data service in the spatial information sector. For this purpose, the Korean Peninsula was set as the projection region and the projection distortion in the projection region was analyzed. The projection parameters were defined to homogenize and minimize the projection distortion, and their standardization and registration on the international organizations were conducted. The study on the required optimal projection equation resulted in the Hooijberg projection equation and projection parameters (${\Phi}$, ${\lambda}$, K, N, E) resulted in $38^{\circ}N$ and $128^{\circ}E$ projection origin, and a scale factor of 0.99924. The proper false northing and easting were 700,000m N and 400,000m E, respectively, considering the introduction of country station index system.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10b
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• pp.208-210
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• 2003

기존의 바다-II는 늦은 프로젝션(late projection) 기법을 사용하기 때문에 중간 임시 결과 파일의 디스크 쓰기와 디스크 읽기에 많은 디스크 자원, 메모리 자원, 그리고 CPU 시간이 소모되었다. 본 논문은 바다-II에 조기 프로젝션(early projection) 기법의 설계와 구현 그리고 그에 따른 성능 향상을 보인다.

• Journal of the Korean Data and Information Science Society
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• v.5 no.1
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• pp.1-10
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• 1994

Projection pursuit(PP) is a computer-intensive method which seeks out interesting linear projections of multivariate data onto a lower dimension space by machine. By working with lower dimensional projections, projection pursuit avoids the sparseness of high dimensional data. We show through simulation that two projection pursuit discriminant mothods proposed by Chen(1989) and Huber(1985) do not improve very much the error rate than the existing methods and compare several classification procedures.

• Journal of Korea Multimedia Society
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• v.20 no.2
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• pp.298-312
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• 2017

The fourth industrial revolution is expected to show technological innovation that develops among different fields beyond boundaries through the convergence and integration of fields. With the development and convergence of digital technology, users can receive information anywhere in the world. In this paper, we propose an adaptive interaction concept in a various environment by using a mobile robot based on projection augmented reality (AR). Most previous studies have aimed fixed projector or projection for a pre-designed environment. Thus, they provide only limited information. To overcome the abovementioned problem, we provide the adaptive information by implementing a projection AR system that can be mounted on the mobile robot. For that, the mobile robot based on the projection system was defined as Pervasive AR. Pervasive AR is configured with a pervasive display, a pervasive interface, and seamless interaction. The Pervasive AR technology enables the user to access information immediately by expanding the display area into real space, which implies an environment of intuitive and convenient interaction by expanding the user interface. This system can be applied to various areas, such as a home environment and a public space.

• Proceedings of the Korean Information Science Society Conference
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• 2006.06a
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• pp.100-102
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• 2006

본 논문에서는 반짝이는 물체를 촬영하여 획득된 이미지로부터 반짝이는 특성을 제거하기 위한 방법으로 color line projection을 제안한다. Color line projection 이란 반짝이는 물체에 대한 color line이 생성되어 있다고 가정하면 하이라이트를 제거하거나 반짝이는 특성을 제거하기 위해 반짝이는 성분을 지닌 색을 specular color line을 따라 diffuse color line에 투영하는 방법이다. 이를 활용하기 위해서는 촬영된 단일 색상을 잘 표현하는 color line이 필요하고 반짝이는 특성을 제거하려는 대상이 되는 색의 구분하는 작업이 선행되어야 한다. 본 논문에서는 color line projection에 대한 개념과 구현하기 위한 방법을 제안하고 이를 활용하는 예제로 반짝이는 성분을 지닌 픽셀들로부터 반짝이는 특성을 제거하는 방법에 적용하는 방법을 제시할 것이다. 또한 결과에서 color line projection이 아닌 다른 방법을 통해 반짝이는 특성을 제거한 결과와 비교함으로써 color line projection의 장점을 실제 이미지를 통해 검증할 것이다.