• Title/Summary/Keyword: Robust adaptive algorithm

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Stereo Vision Based 3-D Motion Tracking for Human Animation

  • Han, Seung-Il;Kang, Rae-Won;Lee, Sang-Jun;Ju, Woo-Suk;Lee, Joan-Jae
    • Journal of Korea Multimedia Society
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    • v.10 no.6
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    • pp.716-725
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    • 2007
  • In this paper we describe a motion tracking algorithm for 3D human animation using stereo vision system. This allows us to extract the motion data of the end effectors of human body by following the movement through segmentation process in HIS or RGB color model, and then blob analysis is used to detect robust shape. When two hands or two foots are crossed at any position and become disjointed, an adaptive algorithm is presented to recognize whether it is left or right one. And the real motion is the 3-D coordinate motion. A mono image data is a data of 2D coordinate. This data doesn't acquire distance from a camera. By stereo vision like human vision, we can acquire a data of 3D motion such as left, right motion from bottom and distance of objects from camera. This requests a depth value including x axis and y axis coordinate in mono image for transforming 3D coordinate. This depth value(z axis) is calculated by disparity of stereo vision by using only end-effectors of images. The position of the inner joints is calculated and 3D character can be visualized using inverse kinematics.

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Speed Control of Induction Motor using Minimum Variance Control Theory (최소분산제어론을 이용한 유도전동기의 속도제어)

  • 오원석;신태현
    • The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.10 no.5
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    • pp.83-93
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    • 1996
  • In this paper, a minimum variance control system is proposed and practically implemented, which is adequate to the induction motor speed control system with frequent load variation. Minimum variance control method is used as a control law and recursive least square method with selective forgetting factor is proposed and analyzed with general forgetting algorithm as an estimation method. Designed control system is based on PC-DSP structure for the purposed of easiness of applying adaptive algorithm. Through computer simulation and experimental results, it is verified that proposed control system is robust to the load variation and practical implementation is possible.

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Development of Face Tracking System Using Skin Color and Facial Shape (얼굴의 색상과 모양정보를 이용한 조명 변화에 강인한 얼굴 추적 시스템 구현)

  • Lee, Hyung-Soo
    • The KIPS Transactions:PartB
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    • v.10B no.6
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    • pp.711-718
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    • 2003
  • In this paper, we propose a robust face tracking algorithm. It is based on Condensation algorithm [7] and uses skin color and facial shape as the observation measure. It is hard to integrate color weight and shape weight. So we propose the method that has two separate trackers which uses skin color and facial shape as the observation measure respectively. One tracker tracks skin colored region and the other tracks facial shape. We used importance sampling technique to limit sampling region of two trackers. For skin-colored region tracker, we propose an adaptive color model to avoid the effect of illumination change. The proposed face tracker performs robustly in clutter background and in the illumination changes.

Direct Torque Control of Squirrel Cage Typed Induction Motor Using Fuzzy Controller (퍼지제어기를 이용한 농형 유도 전동기의 직접 토크제어)

  • Han, Sang-Soo
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.12 no.1
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    • pp.122-129
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    • 2008
  • The direct torque control method of an inverter fed squirrel cage typed induction motor using fuzzy logic controller has been proposed. This method is suitable for the traction which requires a fast torque response during the star-up and step change. The fuzzy control algorithm based upon the control principles of conventional DSC(Direct Self Controller) is developed. The fuzzy algorithm is tarried out by defuzzification strategy of the fuzzy output extracted from the possibility distribution of an inferred fuzzy control rule. The flux and torque of an induction motor are estimated by the dynamic model of the rotor flux field-oriented scheme which has decoupling characteristics and excellent dynamic response over a wide speed range. The proposed controller shows a good dynamic response. Moreover, since the fuzzy controller possesses highly adaptive capability, the performance of fuzzy controller is quite robust and insensitive to the motor parameters and change of operation conditions.

Orientation-based Adaptive Prediction for Effective Lossless Image Compression (효과적인 무손실 영상압축을 위한 방향성 기반 적응적 예측 방법)

  • Kim, Jongho
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.19 no.10
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    • pp.2409-2416
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    • 2015
  • This paper presents an orientation-based adaptive prediction method for effective lossless image compression. For a robust prediction, the proposed method estimates the directional information and the property near the current pixel in a support region-based fashion, not a pixel-based one which is sensitive to a small variation. We improve the prediction performance effectively by selection of the prediction pixel adaptively according to the similarity between support regions of the current pixel and the neighboring pixels. Comprehensive experiments demonstrate that the proposed scheme achieves excellent prediction performance measured in entropy of the prediction error compared to a number of conventional prediction methods such as MED, GAP, and EDP. Moreover the complexity of the proposed algorithm measured by average execution time is low compared to MED which is the simplest prediction method.

Adaptive Beamforming Technique of Eigen-space Smart Antenna System (고유공간 스마트 안테나 시스템의 적응 빔형성 기술)

  • 김민수;이원철;최승원
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.13 no.10
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    • pp.989-997
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    • 2002
  • This paper presents a new technique that enhances the performance of the smart antenna system especially in signal environments of wide angular spread by adopting a weight vector obtained from two eigenvectors of theautocovariance matrix of the received data. While the conventional beamformingtechnique employs only one eigenvector corresponding to the largest eigenvalue, the proposed algorithm uses two eigenvectors corresponding to the largest and second largest eigenvalue in such a way that it can be robust enough to the signal environments of wide angular spread. An efficient adaptive procedure is shown to verify that the optimal weight vector consisting of the two eigenvectors is obtained with a reasonable complexity(3.5N2+ 12N) and accuracy. it is also shown in this paper that the numerical results obtained from the proposed adaptive procedure well agree with those obtained from a commercial tool computing the eigen-function of MATLABTM.

Safe Adaptive Headlight Controller with Symmetric Angle Sensor Compensator Using Steering-swivel Angle Lookup Table (조향각-회전각 룩업테이블을 이용한 대칭형 각도센서 보상기를 가지는 안전한 적응형 전조등 제어기의 설계)

  • Youn, Jiae;An, Joonghyun;Yin, Meng Di;Cho, Jeonghun;Park, Daejin
    • Transactions of the Korean Society of Automotive Engineers
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    • v.24 no.1
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    • pp.112-121
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    • 2016
  • AFLS (Adaptive front lighting system) is being applied to improve safety in driving automotive at night. Safe embedded system design for controlling head-lamps is required to improve noise robust ECU hardware and software simultaneously by considering safety requirement of hardware-dependent software under severe environmental noise. In this paper, we propose an adaptive headlight controller with a newly-designed symmetric angle sensor compensator, especially based on the proposed steering-swivel angle lookup table to determine whether the current controlling target is safe. The proposed system includes an additional backup hardware to compare the system status and provides safe swivel-angle management using a controlling algorithm based on the pre-defined lookup table (LUT), which is a symmetric mapping relationship between the requested steering angle and expected swivel angle target. The implemented system model shows that the proposed architecture effectively detects abnormal situations and restores safe status of controlling the light-angle in AFLS operations under severe noisy environment.

Swarm Based Robust Object Tracking Algorithm Using Adaptive Parameter Control (적응적 파라미터 제어를 이용하는 스웜 기반의 강인한 객체 추적 알고리즘)

  • Bae, Changseok;Chung, Yuk Ying
    • The Journal of Korean Institute of Next Generation Computing
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    • v.13 no.5
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    • pp.39-50
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    • 2017
  • Moving object tracking techniques can be considered as one of the most essential technique in the video understanding of which the importance is much more emphasized recently. However, irregularity of light condition in the video, variations in shape and size of object, camera motion, and occlusion make it difficult to tracking moving object in the video. Swarm based methods are developed to improve the performance of Kalman filter and particle filter which are known as the most representative conventional methods, but these methods also need to consider dynamic property of moving object. This paper proposes adaptive parameter control method which can dynamically change weight value among parameters in particle swarm optimization. The proposed method classifies each particle to 3 groups, and assigns different weight values to improve object tracking performance. Experimental results show that our scheme shows considerable improvement of performance in tracking objects which have nonlinear movements such as occlusion or unexpected movement.

Study on CGM-LMS Hybrid Based Adaptive Beam Forming Algorithm for CDMA Uplink Channel (CDMA 상향채널용 CGM-LMS 접목 적응빔형성 알고리듬에 관한 연구)

  • Hong, Young-Jin
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.32 no.9C
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    • pp.895-904
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    • 2007
  • This paper proposes a robust sub-optimal smart antenna in Code Division Multiple Access (CDMA) basestation. It makes use of the property of the Least Mean Square (LMS) algorithm and the Conjugate Gradient Method (CGM) algorithm for beamforming processes. The weight update takes place at symbol level which follows the PN correlators of receiver module under the assumption that the post correlation desired signal power is far larger than the power of each of the interfering signals. The proposed algorithm is simple and has as low computational load as five times of the number of antenna elements(O(5N)) as a whole per each snapshot. The output Signal to Interference plus Noise Ratio (SINR) of the proposed smart antenna system when the weight vector reaches the steady state has been examined. It has been observed in computer simulations that proposed beamforming algorithm improves the SINR significantly compared to the single antenna case. The convergence property of the weight vector has also been investigated to show that the proposed hybrid algorithm performs better than CGM and LMS during the initial stage of the weight update iteration. The Bit Error Rate (BER) characteristics of the proposed array has also been shown as the processor input Signal to Noise Ratio (SNR) varies.

Sparse Adaptive Equalizer for ATSC DTV in Fast Fading Channels (고속페이딩 채널 극복을 위한 ATSC DTV용 스파스 적응 등화기)

  • Heo No-Ik;Oh Hae-Sock;Han Dong Seog
    • Journal of Broadcast Engineering
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    • v.10 no.1 s.26
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    • pp.4-13
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    • 2005
  • An equalization algorithm is proposed to guarantee a stable performance in fast fading channels for digital television (DTV) systems from the advanced television system committee (ATSC) standard. In channels with high Doppler shifts, the conventional equalization algorithm shows severe performance degradation. Although the conventional equalizer compensates poor channel conditions to some degree, long filter taps required to overcome long delay profiles are not suitable for fast fading channels. The Proposed sparse equalization algorithm is robust to the multipaths with long delay Profiles as well as fast fading by utilizing channel estimation and equalizer initialization. It can compensate fast fading channels with high Doppler shifts using a filter tap selection technique as well as variable step-sizes. Under the ATSC test channels, the proposed algorithm is analyzed and compared with the conventional equalizer. Although the proposed algorithm uses small number of filter taps compared to the conventional equalizer, it is stable and has the advantages of fast convergence and channel tracking.