• 전자공학회논문지B
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• 제31B권2호
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• pp.45-55
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• 1994

In this paper, a block based image approximation technique using the Self Affine System(SAS) from the fractal theory is suggested. Each block of an image is divided into 4 tiles and 4 affine mapping coefficients are found for each tile. To find the affine mapping cefficients that minimize the error between the affine transformed image block and the reconstructed image block, the matrix euation is solved by setting each partial differential coefficients to aero. And to ensure the convergence of coding block. 4 uniformly partitioned affine transformation is applied. Variable block size technique is employed in order to applynatural image reconstruction property of fractal image coding. Large blocks are used for encoding smooth backgrounds to yield high compression efficiency and texture and edge blocks are divided into smaller blocks to preserve the block detail. Affine mapping coefficinets are found for each block having 16$\times$16, 8$\times$8 or 4$\times$4 size. Each block is classified as shade, texture or edge. Average gray level is transmitted for shade bolcks, and coefficients are found for texture and edge blocks. Coefficients are quantized and only 16 bytes per block are transmitted. Using the proposed algorithm, the computational load increases linearly in proportion to image size. PSNR of 31.58dB is obtained as the result using 512$\times$512, 8 bits per pixel Lena image.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.358-360
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• 2004

The digital images contain a significant amount of redundancy and require a large amount of data for their storage and transmission. Therefore, the image compression is necessary to treat digital images efficiently. The goal of image compression is to reduce the number of bits required for their representation. The image compression can reduce the size of image data using contractive mapping of original image. Among the compression methods, the mapping is affine transformation to find the block(called range block) which is the most similar to the original image. In this paper, we applied the neural network(SOM) in encoding. In order to improve the performance of image compression, we intend to reduce the similarities and unnecesaries comparing with the originals in the codebook. In standard image coding, the affine transform is performed with eight isometries that used to approximate domain blocks to range blocks.

• 한국지능시스템학회논문지
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• 제5권3호
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• pp.3-10
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• 1995

This paper proposedan on-line learning controller which can be applied to nonlinear systems. The proposed on-line learning controller is based on the universal approximation by the local affine mapping-based neural networks. It has self-organizing and learning capability to adapt itself to the new environment arising from the variation of operating point of the nonlinear system. Since the learning controller retains the knowledge of trained dynamics, it can promptly adapt itself to situations similar to the previously experienced one. This prompt adaptability of the proposed control system is illustrated through simulations.

• 대한전자공학회논문지SP
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• 제39권2호
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• pp.1-10
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• 2002

이 논문에서는 크기와 영상 평면상에서 회전 (in-plane rotation) 변화를 가지는 정면 얼굴 영상의 인식성능을 향상시키기 위하여, 새로운 템플릿 (template) 기반 접근 방법들을 제안한다. 인식 성능을 향상시키기 위한 템플릿들은 크기와 회전 변화가 다른 다수의 영상들을 선형 또는 비선형 연산에 의하여 생성된다. 얼굴의 크기와 영상 평면에서 회전 변화에 무관한 얼굴의 특징을 추출하기 위하여 어파인 (affine) 변환, 로그폴라 (log-polar) 사상, 그리고 로그폴라 영상에 기반한 FFT들이 이용된다. 제안된 방법들은 인식률과 수행 시간 측면에서 비교된다. 실험 결과로부터 제안된 템플릿을 이용한 방법들의 인식률이 한 장의 영상으로 생성된 템플릿을 이용한 방법들의 인식률보다 우수함을 나타낸다. 어파인 변환을 이용한 방법의 인식률이 로그폴라 사상을 이용한 방법과 로그폴라 영상에 기반한 FFT 방법의 인식률보다 우수하며, 수행 시간 측면에서는 로그폴라 사상을 이용한 방법이 가장 빠르다.

• 전자공학회논문지B
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• 제32B권5호
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• pp.812-820
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• 1995

This paper proposes an approach of identifying nonlinear mappings from input/output data. The approach is based on the universal approximation by the fuzzy integration of local affine mappings. A connectionist model realizing the universal approximator is suggested by using a processing unit based on both the radial basis function and the weighted sum scheme. In addition, a learning method with self-organizing capability is proposed for the identifying of nonlinear mapping relationships with the given input/output data. To show the effectiveness of our approach, the proposed model is applied to the function approximation and the prediction of Mackey-Glass chaotic time series, and the performances are compared with other approaches.

• 대한공간정보학회지
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• 제16권4호
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• pp.79-87
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• 2008

위성측량이나 기존의 항공측량에 비해 경제적이면서 기상영향을 덜 받는 저고도 고해상 영상의 취득과 항공사진측량의 많은 수요를 충족하기 위해 신속한 맵핑을 위한 UAV(Unmanned Aerial Vehicle) 기술 개발이 요구되고 있으며, 특히 효율적인 지형보정에 관한 연구가 중요한 이슈로 부각되고 있다. 그러나, 민간분야 활용을 위한 UAV의 높은 잠재력에 비해 최근까지 직접 지형보정과 같은 사진측량측면에서의 기술개발은 초기 단계에 머물고 있으며, 지속적인 연구와 추가적인 기술개발 노력이 필요하다. 본 연구에서는 최소한의 지상기준점 정보를 이용하여 간편한 부등각사상변환식과 부등각사상변환의 블록조정에 의해 자동으로 저고도 UAV 영상을 기하보정하는 기법을 제안하였으며, 상용 프로그램 처리결과와 비교를 통하여 UAV 정지영상 기하모형식으로서의 적용가능성을 평가하였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 추계종합학술대회 논문집
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• pp.1085-1088
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• 1999

This paper presents a method for soccer scene analysis and coordinate transformation from scene to ground model using a priori knowledge. First, the ground and spectator regions are separated, and various objects are extracted from the separated ground region. Second, an affine model is used for mapping the object positions on the soccer image into the position on the ground model. Problems regarding holes arising from mapping processing are solved using inverse mapping instead of a usual interpolation method. Experiments are performed on a PC using about 100 RGB images acquired at 240＊640 resolution and 3∼5 frames per second.

• 대한수학회보
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• 제50권2호
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• pp.675-685
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• 2013

We prove, under some general assumptions, that a generator of any uniformly bounded Nemytskij operator, mapping a subset of space of functions of bounded variation in the sense of Wiener-Young into another space of this type, must be an affine function with respect to the second variable.

• 대한수학회보
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• 제50권5호
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• pp.1631-1637
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• 2013

This paper generalizes the Aleksandrov problem and Mazur Ulam theorem to the case of $n$-normed spaces. For real $n$-normed spaces X and Y, we will prove that $f$ is an affine isometry when the mapping satisfies the weaker assumptions that preserves unit distance, $n$-colinear and 2-colinear on same-order.

• 전자공학회논문지A
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• 제32A권8호
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• pp.11-18
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• 1995

This paper proposes a nonlinear adaptive equalizer which is based on fuzzy rules and fuzzy inference of several affine mapping for the received channel data. The proposed nolonlinear adaptive equalizers with the significantly lower computational complexity. Also it can be applied to the on-line adaptation environments owing to its fast convergence characteristics and the lower computational load. When using the decision feedback vectors, this equaalizer can be easily realized in the form of the DFE structure with out the requirement for the perfect channel knowledge as in the case of the fuzzy adaptive filter.