• Journal of Sensor Science and Technology
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• v.6 no.4
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• pp.280-289
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• 1997

The measure of motor speed using encoder is difficult to detect accurate speed and direction in very low speed because the intervals between an encoder pulse and pulse are long. So various speed estimation techniques were proposed to have the good dynamic performance in low speed. And direction detection is so important as speed measurement in very low speed. But because the conventional direction detection circuit check the direction only 1 time in 1 period of each encoder pulses, so it has long delayed detection time in very low speed, thus accurate detection of direction is difficult. In this paper, we propose a 2 way edge detection method which can detect at the rising and filling edge of each encoder pulses. So it can check the direction 4 times in 1 period of each encoder pulses. Therefore if we use proposed method, we can reduce the detection time as 1/4 than that of conventional circuit and can detect more accurate speed and direction. And computer simulation and experiment is performed to verify the perfomance and effect of proposed circuit and we analyze it's results by comparing with that of conventional circuit.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.3
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• pp.553-563
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• 1996

Detecting edges is one of issues with essentialimprotance in the area of image analysis. An edge in an image is a boundary or contour at which a significant change occurs in image intensity. Edge detection has been studied in many addlications such as imagesegmentation, robot vision, and image compression. In this paper, we propose an automatic threshold selection scheme for edge detection and show its application to noise elimination. The scheme suggested here applied statistical properties of the noise estimated from a noisy image to threshold selection. Since a selected threshold value in the scheme depends on not the characgreistic of an orginal image but the statistical feature of added noise, we can remove ad-hoc manners used for selecting the threshold value as well as decide the value theoretically. Furthermore, that shceme can reduce the number of edge pixels either generated or lost by noise. an application of the scheme to noise elimination is shown here. Noise in the input image can be eliminated with considering the direction of each edge pixedl on the edge map obtained by applying the threshold selection scheme proposed in this paper. Achieving significantly improved results in terms of SNR as well as subjective quality, we can claim that the suggested method works well.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.10C
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• pp.1425-1432
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• 2004

Because of the high performance with the edge regions, the existing LSE(Least Square Estimation) method provides much better results than other methods. However, since it emphasizes not oがy edge components but also noise components, some part of interpolated images looks like unnatural. It also requires very high computational complexity and memory for implementation. We propose a new LSE interpolation method which requires much lower complexity and memory, but provides better performance than the existing method. To reduce the computational complexity, we propose and adopt a simple sample window and a direction detector to reduce the size of memory without blurring image. To prevent from emphasizing noise components, the hi-linear interpolation method is added in the LSE formula. The simulation results show that the proposed method provides better subjective and objective performance with love. complexity than the existing method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.11A
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• pp.1880-1888
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• 2001

In wireless communication systems, transmission errors degrade the reconstructed image quality severely. Among various techniques which reduce the degradation, the error concealment technique yields good performance without overheads and the modification of the encoder. In this paper, we have proposed the technique for recovering the corrupted motion vector using the edge direction of blocks which surround the corrupted block, when the video information is compressed by H.263 standard. We uses the property that each object in video sequences shows the same motion. For the estimation of edge directions, the first AC coefficients of blocks are used. Extensive simulation results show that the proposed technique yields good performance with a reduced computational complexity.

• Journal of the Korea Society of Computer and Information
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• v.21 no.10
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• pp.11-19
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• 2016

The size of a display is large, The form becoming various of that do not apply to previous methods of gaze tracking and if setup gaze-track-camera above display, can solve the problem of size or height of display. However, This method can not use of infrared illumination information of reflected cornea using previous methods. In this paper, Robust pupil detecting method for eye's occlusion, corner point of inner eye and center of pupil, and using the face pose information proposes a method for calculating the simply position of the gaze. In the proposed method, capture the frame for gaze tracking that according to position of person transform camera mode of wide or narrow angle. If detect the face exist in field of view(FOV) in wide mode of camera, transform narrow mode of camera calculating position of face. The frame captured in narrow mode of camera include gaze direction information of person in long distance. The method for calculating the gaze direction consist of face pose estimation and gaze direction calculating step. Face pose estimation is estimated by mapping between feature point of detected face and 3D model. To calculate gaze direction the first, perform ellipse detect using splitting from iris edge information of pupil and if occlusion of pupil, estimate position of pupil with deformable template. Then using center of pupil and corner point of inner eye, face pose information calculate gaze position at display. In the experiment, proposed gaze tracking algorithm in this paper solve the constraints that form of a display, to calculate effectively gaze direction of person in the long distance using single camera, demonstrate in experiments by distance.

• Journal of Broadcast Engineering
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• v.18 no.4
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• pp.619-630
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• 2013

In this paper, we propose an edge directed color demosaicing algorithm considering color channel correlation. The proposed method consists of local region classification step and edge directional interpolation step. In the first step, each region of a given Bayer image is classified as normal edge, pattern edge, and flat regions by using intra channel and inter channel gradients. Especially, two criteria and verification process for the normal edge and pattern edge classification are used to reduce edge direction estimation error, respectively. In the second step, edge directional interpolation process is performed according to characteristics of the classified regions. For horizontal and vertical directional interpolations, missing color components are obtained from interpolation equations based on intra channel and inter channel correlations in order to improve the performance of the directional interpolations. The simulation results show that the proposed algorithm outperforms conventional approaches in both objective and subjective terms.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.5
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• pp.143-150
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• 2009

In this paper, we present a spatial domain error concealment method to recover a lost block in intra-coded frames. The edge directions of the lost block are estimated by the difference values of the border pixels of the accurately received blocks. The lost block is interpolated according to the estimated edge directions. Our algorithm can adaptively recover a lost block according to the estimated edge direction. The distances between pixels are used as weights for interpolation. In spite of the low computational cost, the proposed method outperforms the previous methods in objective and subjective qualities.

• ETRI Journal
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• v.38 no.1
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• pp.164-173
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• 2016

Demosaicing, or color filter array (CFA) interpolation, estimates missing color channels of raw mosaiced images from a CFA to reproduce full-color images. It is an essential process for single-sensor digital cameras with CFAs. In this paper, a new demosaicing method for digital cameras with Bayer-like W-RGB CFAs is proposed. To preserve the edge structure when reproducing full-color images, we propose an edge direction-adaptive method using color difference estimation between different channels, which can be applied to practical digital camera use. To evaluate the performance of the proposed method in terms of CPSNR, FSIM, and S-CIELAB color distance measures, we perform simulations on sets of mosaiced images captured by an actual prototype digital camera with a Bayer-like W-RGB CFA. The simulation results show that the proposed method demosaics better than a conventional one by approximately +22.4% CPSNR, +0.9% FSIM, and +36.7% S-CIELAB distance.

• 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.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.11
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• pp.126-137
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• 1997

This paper describes the algorithm which can estimate road following direction and deetect obstacle using a monocular vision system. This algorithm can estimate the course of vehicle using the vanishing point properties and detect obstacle by statistical method. The proposed algorithm is composed of four steps, which are lane prediction, lane extraction, road following parameter estimation and obstacle detection. It is designed for high processing speed and high accuracy. The former is achieved by a small area named sub-windown in lane existence area, the later is realized by using connected edge points of lane. We would like to present that the new mehod can detect obstacle using the simple statistical method. The paracticalities of the processing speed, the accuracy of the algorithm and proposing obstacle detection method, have been justified through the experiment applied VTR image of the real road to the algorithm.