• Journal of the Institute of Electronics Engineers of Korea SP
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• v.40 no.6
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• pp.31-40
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• 2003

Most face recognition systems are based on 2D images and applied in many applications. However, it is difficult to recognize a face when the pose varies severely. Therefore, head pose estimation is an inevitable procedure to improve recognition rate when a face is not frontal. In this paper, we propose a novel head pose estimation algorithm for 3D face recognition. Given the 3D range image of an unknown face as an input, we automatically extract facial feature points based on the face curvature. We propose an Error Compensated Singular Value Decomposition (EC-SVD) method based on the extracted facial feature points. We obtain the initial rotation angle based on the SVD method, and perform a refinement procedure to compensate for remained errors. The proposed algorithm is performed by exploiting the extracted facial features in the normaized 3D face space. In addition, we propose a 3D nearest neighbor classifier in order to select face candidates for 3D face recognition. From simulation results, we proved the efficiency and validity of the proposed algorithm.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.49 no.7
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• pp.30-38
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• 2012

This paper presents packet detection, frequency offset estimation architecture and performance analysis for OFDM-based wireless personal area network (WPAN) systems. Packet detection structure is used to find the start point of a packet exactly in WPAN system as the correlation value passes the constant threshold value. The applied autocorrelation structure of the algorithm can be implemented simply compared to conventional packet detection algorithms. The proposed frequency offset estimation architecture is designed for phase rotation process structure, internal bit reduction to reduce hardware size and the frequency offset adjustment block to reduce look-up table size unlike the conventional structure. If the received signal can be compensated by estimated frequency offset through the correction block, it can reduce the impact on the frequency offset. Through the performance result, the proposed structure has lower hardware complexity and gate count compared to the conventional structure. Thus, the proposed structure for OFDM-based WPAN systems can be applied to the initial synchronization process and high-speed low-power WPAN chips.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.12
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• pp.1245-1255
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• 2012

There are various anti-jamming algorithms for the GNSS system which is vulnerable to jamming, and the methods using array antenna show the best performance. Among them, the DOA estimation algorithms to identify the location of the jammer is very important. However, in case of the rotorcraft, the wireless channel which amplitude and phase changes with time is generated by the rotation of the rotor and it affects the performance of existing anti-jamming algorithms. In this paper, we modeled the effect of the rotor in four scenarios according to the correlation of antennas and assured that the performance of DOA estimation algorithms are degraded and saturated regardless of JNR due to the rotor effect. When we use the averaging method to solve this problem, the performance is improved as increasing samples for estimating. And in case of using moving average method with averaging, it shows similar performance. In addition, it reduces the required memory and moderates the variation of DOA estimation.

• Smart Media Journal
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• v.5 no.1
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• pp.38-43
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• 2016

As smart environment is spread out in our living environments, the needs of an approach related to Human Computer Interaction(HCI) is increases. One of them is head pose estimation. it related to gaze direction estimation, since head has a close relationship to eyes by the body structure. It's a key factor in identifying person's intention or the target of interest, hence it is an essential research in HCI. In this paper, we propose an approach for head pose estimation with pre-defined several directions by random forest classifier. We use canny edge detector to extract feature of the different facial image which is obtained between input image and averaged frontal facial image for extraction of rotation information of input image. From that, we obtain the binary edge image, and make two accumulated histograms which are obtained by counting the number of pixel which has non-zero value along each of the axes. This two accumulated histograms are used to feature of the facial image. We use CAS-PEAL-R1 Dataset for training and testing to random forest classifier, and obtained 80.6% accuracy.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.1 s.244
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• pp.60-65
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• 2006

The present paper provides experimental J estimation equation for the circumferential through-wall cracked pipe under four-point bending, based on the load-crack opening displacement (COD) record. Based on the limit analysis and the kinematically admissible rigid-body rotation field, the plastic ${\eta}$-factor for the load-COD record is derived and is compared with that for the load-load line displacement record. Comparison with the J results from detailed elastic-plastic finite element (FE) analysis shows that the proposed method based on the load-COD record provides reliable J estimates even for shallow cracks, whereas the conventional approach based on the load-load line displacement record gives erroneous results for shallow cracks. Thus, the proposed J estimation method could be recommended for testing the circumferential through-wall cracked pipe, particularly with shallow cracks.

• Journal of Korea Multimedia Society
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• v.13 no.4
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• pp.547-559
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• 2010

Delaunay triangulation is suitable for fingerprint matching because of its robustness to rotation and translation. However, missing and spurious minutiae degrade the performance and computational efficiency. In this paper, we propose a method of combining local quality assessment and 4-category minutiae classification to improve accuracy and decrease computational complexity in matching process. Experimental results suggest that removing low quality areas from matching candidate areas and classifying minutiae improve computational efficiency without degrading performance. The results proved that the proposed algorithm outperforms the matching algorithm (BOZORTH3) provided by NIST.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.10
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• pp.1516-1522
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• 2017

We propose a novel monitoring system for diagnosing crack faults of the wind turbine using image information. The proposed method classifies a normal state and a abnormal state for the blade parts of the wind turbine. Specifically, the images are input to the proposed system in various states of wind turbine rotation. according to the blade condition. Then, the video of rotating blades on the wind turbine is divided into several image frames. Motion vectors are estimated using the previous and current images using the motion estimation, and the change of the motion vectors is analyzed according to the blade state. Finally, we determine the final blade state using the Support Vector Machine (SVM) classifier. In SVM, features are constructed using the area information of the blades and the motion vector values. The experimental results showed that the proposed method had high classification performance and its $F_1$ score was 0.9790.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.7C
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• pp.706-712
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• 2006

In this letter, we propose a compact CORDIC processor for implementation of carrier frequency synchronization block in an OFDM (Orthogonal Frequency Division Multiplexing) system. The compact CORDIC processor is proposed by using inherenct properties of an OFDM system for estimation and compensation of carrier frequency offset, and is composed of a compact CORDIC preprocessor and a compact CORDIC processor. The compact CORDIC preprocessor plays a role of normalizing input signal efficiently, and the compact CORDIC processor is proposed to perform the vectoring mode and rotational mode jointly in CORDIC operation for carrier frequency synchronization. It is shown by FPGA implementation that the proposed compact CORDIC processor can achieve better performance with a significantly reduced hardware complexity than the conventional CORDIC approach.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.5
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• pp.361-368
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• 2015

This paper deals with a robust fine seek controller design problem with multiple constraints using a genetic algorithm. A robust $H\infty$ constraint is introduced to attenuate effectively velocity disturbance caused by the eccentric rotation of the disk. A weighting function is optimally selected based on the estimation of velocity disturbance and the estimated minimum velocity loop gain. A robust velocity loop constraint is considered to minimize the variances of the velocity loop gain and bandwidth against the uncertainties of fine actuator. Finally, a robust fine seek controller is obtained by solving a genetic algorithm with an LMI condition and an appropriate objective function. The proposed controller design method is applied to the fine seek control system of a DVD recording device and is evaluated through the experimental results.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.8 s.227
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• pp.1221-1228
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• 2004

The vertical roller mill is the important machine grinding and mixing various crude materials in the manufacturing process of portland cement. Table liner is one of grinding elements of vertical roller mill and is subjected to the cyclic bending stress by rollers load and the centrifugal force by rotation of table. It demands $4{\times}10^7$ cycle but has $4{\times}10^6{\sim}8{\times}10^6$ cycle. It fractures at the edge of grinding path of outside roller. The repair expense for it amounts to $30\%$ of total maintenance of vertical roller mill. Therefore, this study shows the fracture mechanism of table liner for vertical roller mill using HDM and fatigue analysis and makes the estimation for safety of vertical roller mill.