• Journal of the Institute of Electronics Engineers of Korea CI
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• v.41 no.6
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• pp.101-109
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• 2004

This paper proposes an adaptive watermarking algerian technique concerning the visual characteristics of human. To embed watermark to an image, features such as contrast, brightness, and texture are used. The propose method adaptively select blocks and determine the position and intensity of watermark to be applied, concerning the visual characteristics of a human. The experiment involves cropping, image enhancement, low pass filtering, and JPEG compression, which are compared on detectability of watermark against image manipulation and attack

• Proceedings of the IEEK Conference
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• 2003.07e
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• pp.1903-1906
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• 2003

This paper proposes an adaptive regularized noise smoothing algorithm for range image using the area decreasing flow method, which can preserve meaningful edges during the smoothing process. Although the area decreasing flow method can easily smooth Gaussian noise, it has two problems; ⅰ) it is not easy to remove impulsive noise from observed range data, and ⅱ) it is also difficult to remove noise near edge when the adaptive regularization is used. In the paper, therefore, the second smoothness constraint is addtionally incorporated into the existing regularization algorithm, which minimizes the difference between the median filtered data and the estimated data. As a result, the Proposed algorithm can effectively remove the noise of dense range data with edge preserving.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.7
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• pp.332-338
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• 2000

In this paper, a robust nonlinear excitation controller is proposed to achieve both voltage regulation and system stability enhancement for single machine-infinite power systems. The proposed method employs backstepping technique and combines this with an adaptation algorithm for estimating the effective reactance of transmission line, thereby leading to adaptive nonlinear control. Simulation results show that power that angle stabilization as well as voltage regulation is achieved in a satisfactory manner, regardless of the system operating conditions and system structure.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.7
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• pp.1505-1514
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• 1997

In this paper, a temporally adaptive layered image sequence coding technique employing H.261 is proposed. In the proposed technique, the frame rate of the base layer is adjusted according to the temporal activity measure based on the rate-distortion function. The base layer is encoded using the H.261. Then, the full frame-rate error image is formed by comparing the original image and the interpolated version of the reconstructed base layer image. The enhancement layer is algo encoded using H.261 but with leaky prdiction to provide robust error resilience. The simulation results show that the proposed technique provides better performance than the twin-H.261 with leaky prediction in both the fixed-rate and variable-rate systems.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.15 no.12
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• pp.1031-1043
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• 1990

A sequential recursive Kalman filtering algorithm, using causal image model, which is designed to operate in real time in the scanning mode is developed to enhance quality of 64Kbps videocodec images via function of suppression of various noises and optimum restoration. In order to improve its performance, adapted an averaging of pixel values between processing lines and adaptive filtering strategy based on the local spatial variance. Effecttiveness of the Kalman filtering algorithm proposed has been proved in the processed test kalman filtering algorithm proposed has been proved in the processed test images and the NMSE, LOGMSE measured, therefore, it may proposes possibility of the usage in videocodec for pre- and post- processing.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.91-92
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• 2007

LR-UWB utilizes BPSK and PPM for the transmission, which embeds the information in the transmitted pulse position. Meanwhile, by using coherent method, there is approximately 3dB enhancement on the BER performance over that using non-coherent method. However, due to the variable channel conditions, conventional system which uses fixed modulation is not efficient. To maximize the efficient and performance, in this paper, we propose an adaptive method including 4PPM+BPSK mode and 2PPM mode, in which the modulation method is dynamically changed depending on the channel condition which is determined according to the preamble correlation output.

• Journal of the Semiconductor & Display Technology
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• v.14 no.4
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• pp.92-97
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• 2015

The purpose of this work is to support a solution of optimizing TMO (tone mapping operator). JPEG XT Profile A and C utilize Erik Reinhard TMO that works well in most cases, however, detailed information of a scene is lost in some cases. Reinhard TMO only calculates its coefficient to have tone-mapping curve from log-average luminance, and this lead to lose details of bright and dark area of scenes in turn. Thus, this paper proposes an enhancement of the default TMO for JPEG XT Profile C to optimize tone-mapping curve. Main idea is that we divide tone mapping curve into several ranges, and set reasonable parameters for each range. By the experimental results, the proposed scheme shows and obtains better performance within a dark scene, compared to the default Reinhard TMO.

• Proceedings of the KIEE Conference
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• 1987.07a
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• pp.144-147
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• 1987

An adaptive control algorithm for a plant with unmodelled dynamics is proposed. The upper bounds of the output due to the unmodelled dynamics and measurement noise is assumed to be known. Linear programming is used in estimating the bounds of plant parameters. Projection type algorithm is used in estimating the plant parameter with these bounds. This algorithm is nearly the same as those proposed by Kreisselmeier or Middleton except that the bounds are computed by linear programming. The stability of the proposed algorithm Can be proved in nearly the same way as that of Middleton. Simulation results show that the proposed algorithm gives better parameter convergence and smaller overshoot in the plant output than the algorithm without computing the bounds of plant parameters by linear programming.

• Annual Conference of KIPS
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• 2008.05a
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• pp.84-87
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• 2008

본 논문에서는 Q.Wang & R.K.Ward 가 제안한 WTHE(weighted and thresholded histogram equalization)방법의 enhancement parameters를 주어진 영상의 히스토그램 분포에 따라 적응적으로 제공하는 방법을 제안한다. WTHE는 영상의 히스토그램을 weight와 threshold를 이용하여 변형한 후 히스토그램 평활화(histogram equalization : HE)방법을 수행 함으로써 화질을 개선하는 방법이다. 이 방법은 두 가지 parameters 제어로 기존의 히스토그램 평활화 방법의 단점인 과도한 밝기 변화와 불필요한 artifacts를 줄일 수 있다. 본 논문에서는 WTHE 방법을 좀 더 간편하면서 다양한 분야에 적용하기 위해서 입력 영상에 따라 달라지는 parameters 값을 자동으로 제공하는 적응형 WTHE(Adaptive WTHE : AWTHE) 방법을 제안하고, 제안된 방법의 성능을 실험으로 제시한다.

• The Journal of the Acoustical Society of Korea
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• v.23 no.2E
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• pp.56-67
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• 2004

Despite abundant research outcomes of blind source separation (BSS) in many types of simulated environments, their performances are still not satisfactory to be applied to the real environments. The major obstacle may seem the finite filter length of the assumed mixing model and the nonlinear sensor noises. This paper presents a two-step speech enhancement method with multiple microphone inputs. The first step performs a frequency-domain BSS algorithm to produce multiple outputs without any prior knowledge of the mixed source signals. The second step further removes the remaining cross-channel interference by a spectral cancellation approach using a probabilistic source absence/presence detection technique. The desired primary source is detected every frame of the signal, and the secondary source is estimated in the power spectral domain using the other BSS output as a reference interfering source. Then the estimated secondary source is subtracted to reduce the cross-channel interference. Our experimental results show good separation enhancement performances on the real recordings of speech and music signals compared to the conventional BSS methods.