• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.12B
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• pp.2349-2358
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• 1999

Object-based stereoscopic video coding scheme is presented in this paper. In conventional BMA based stereoscopic video coding for low bit rate transmission, image prediction errors such as block artifacts and mosquito phenomena are occurred. In order to reduce these errors, object based coding scheme is adopted. The proposed scheme consists of preprocessing, object extraction, and object update procedures. The preprocessing procedure extracts non-object regions having low reliability for motion and disparity estimation. This procedure prohibits extracting inaccurate objects. For the better prediction of left channel image, the disparity information is added to the object extraction. And the proposed algorithm can reduce the accumulated error through the object update procedure that detects newly emerging objects, merges objects that have the same object-disparity and object motion, and splits object which has large image prediction error. The experimental results show that the proposed algorithms improve the quality of the prediction without block artifacts and mosquito phenomena.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.12C
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• pp.1232-1239
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• 2006

In video standards such as MPEG-1/2/4 and H.264/AVC, motion estimation / compensation(ME/MC) process causes the most encoding complexity of video encoder. The full search method, which is used in general video codecs, exhausts much encoding time because it compares current macroblock with those at all positions within search window for searching a matched block. For the alleviation of this problem, the fast search methods such as TSS, NTSS, DS and HEXBS are exploited at first. Thereafter, DS based MVFAST, PMVFAST, MAS and FAME, which utilize temporal or spacial correlation characteristics of motion vectors, are developed. But there remain the problems of image quality degradation and algorithm complexity increase. In this thesis, the proposed algorithm maximizes search speed and minimizes the degradation of image quality by determining initial search point correctly and using simple one-dimension search patterns considering motion characteristics of each frame.

• The Journal of Information Technology
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• v.3 no.2
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• pp.39-47
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• 2000

Among the compression methods of moving picture information, a motion estimation method is used to remove time-repeating. The Block Matching Algorithm in motion estimation methods is the commonest one. In recent days, it is required the more advanced high quality in many image processing fields, for example HDTV, etc. Therefore, we have to accomplish not by means of Partial Search Algorithm, but by means of Full Search Algorithm in Block Matching Algorithm. In this paper, it is suggested a structure that reduce total calculation quantity and size, because the structure using Bit Plane select and use only 3bit of 8bit luminance signal.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.36T no.4
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• pp.103-109
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• 1999

In this paper, we proposed to a new structure of T-shaped fed microstrip slot antenna using 2-layers dielectric material with a directional radiation characteristic. When the slot antenna of bi-directional radiation want to radiate only one direction, the reflector must be set up, but this antenna does'nt need set up reflector. T-shaped microstrip feed line is proposed for a better impedance matching to the microstrip slot antenna in a various range of slot widths. It was also found that the bandwidth of this antenna is proportional to the slot width. It was also found that the radiation resistance of this feed line structure is quite constant and low regardless to the slot width. We also analyzed this antenna by using the FDTD method, and calculating waves and electric field distribution in the time domain. we also are calculated return loss, VSWR, and radiation pattern in the frequency domain by Fourier transforming the time domain results, respectively. From the measured results, bandwidth was 34.8% in the center frequency. These results were in relatively good accordance with the calculated values.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.2
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• pp.207-213
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• 2008

A simplified design procedure for quasi-Yagi antenna arrays using an ultra-wideband balun is presented. The proposed antenna design procedure is based on the simple impedance matching among antenna components: i.e., balun, feed, and antenna This new broadband and high gain antenna array is possible due to the ultra-wideband performance of the balun. As design examples, wideband $1\times4$ and $1\times8$ quasi-Yagi antenna arrays are successfully designed and implemented in Ku-band with frequency bandwidths of about 50 % and antenna gains of 9$\sim$10 dBi and 11$\sim$12 dBi, respectively. And the simulated and measured results demonstrate wide bandwidths and good radiation properties. These antenna arrays can be applied to various phased-array and spatial power combining systems.

• Journal of IKEEE
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• v.3 no.2 s.5
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• pp.221-225
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• 1999

In this paper, a new type of predistortion linearizer has been studied. It employs a series feedback amplifier with a large source inductance as a predistortion linearizer, which provides positive amplitude and negative phase deviations for input Power and can compensate for AM-AM and AM-PM distortions of power amplifier. This predistortion lineariaer consists of only one CaAs FET, large source inductor, input output matching networks and bias circuits. Because of its simple circuit, the linear can be operated over a broad bandwidth and has good thermal stability The characteristics of this linearizer can be easily tuned using source inductor, its gate bias condition. In fabricated linearizer, the third-order intermodulation distortion(IMD) for main amplifier alone is 10.61dBc, and the $IM_3$ for main amplifier with predistorter is 21.91dBc. Therefore, the $IM_3$ characteristic results an improvement of approximately 11dB.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.5
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• pp.243-250
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• 2002

In the synthesis of the current source distribution function of an array antenna with the arbitrary radiation pattern, the Woodward-Lawson sampling method has been mainly used for the synthesis of an even function lobe pattern. In this paper, the method is extended to the synthesis of the odd function pattern and then the optimum synthesis method for the nonlinear source distribution function is proposed. The proposed method is applied to the design of nonuniform transmission lines with arbitrary reflection responses. The both dispersive impedance profiles of single and coupled nonuniform lines with arbitrary reflection responses are directly synthesized by the sampled values of a reflected spectral pattern which is optimally shaped by a perturbation of its complex null positions, hence removing the conventional step-by-step segmentation process and global optimization routines. The control problem in the case that all of port impedances are identical is also solved. The generality of the proposed method is verified by a filter design with the controlled arbitrary passband

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.6
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• pp.1-8
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• 1998

This paper presents an asynchronous DS/CDMA multiuser detector, which is a two stage, symbol-by-symbol scheme consisting of conventional detectors followed by linear decorrelating detectors. The conventional detector first makes temporal decisions and the detected symbols are delayed by one symbol period to be used for the selection of decorrelating bases in the subsequent decorrelaing detection stage. It also employs a bank of early-late correlators in place of a bank of single correlators taking the small offset of chip timing asynchronism into account. The proposed detector requires only the coarse knowledge of relative time delays of interfering users and is suitable for digital implementation. To verify the detector performance, the analytical BER performance will be given and compared with the simulation results for BPSK DS/CDMA signals in AWGN channel. While the performance of the proposed detector will be analyzed for time-limited signal, the simulation is carried out for both the time-limited and band-limited signals. As can be seen in the simulation results, the proposed scheme shows good results.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.9
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• pp.99-109
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• 2016

This paper presents a method for generating spatiotemporal images to detect the leukocyte motions in a microvessel. By using the constraint that the leukocytes move along the contour line of a blood vessel wall, the method detects leukocyte motions and then generates spatiotemporal images. the translational motion by a movement in vivo is removed first by the template matching method. Next, a blood vessel region is detected by the automatic threshold selection method to binarize the temporal variance image, then a blood vessel wall's contour is expressed by B-spline function. With the detected blood vessel wall's contour as an initial curve, the plasma layer of the best accurate position is determined to be the spatial axis by snake. Finally, the spatiotemporal images are generated. The experimental results show the spatiotemporal images are generated effectively through the comparison of each step of three image sequences.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.49 no.2
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• pp.26-37
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• 2012

In this study, a power driver for actuating PVDF film that has the characteristic of dramatic impedance change caused by size and operating frequency variation was developed to dehyance rate of dredged sediment. In order to supply maximum energy to the PVDF film, a full-bridge circuit implemented using IGBT with a R-L-PVDF film impedance matching circuit was designed and constructed. the dehydration capabilities of the PVDF film actuated by the developed driver cleary was tested for dredged sediment. It was found that the PVDF film actuated by the developed driver cleary enhanced dehydration, avout three times faster during the first 3 minutes, compared to natural dehydration. The result of the experiment confirmed that the developed power driver for actuating Pvdf film could be used effectively for dehydration of dredged sediment.