• The Journal of the Acoustical Society of Korea
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• v.24 no.3E
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• pp.99-108
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• 2005

To investigate the equalizer performance in underwater acoustic communication m the presence of intersymbol interference (ISI) due to multipath, computer simulations are carried out in discrete multipath shallow water channels for three different horizontal ranges. For the purpose of computation simplicity, least mean square (LMS) algorithm is adopted both in linear equalizer and nonlinear equalizer, decision feedback equalizer (DFE) to cancel out ISI effects. Binary phase shift keying (BPSK) signals have been transmitted with high data rate of 2000bps through the use of equalization technique. The results demonstrate that equalization is an efficient way to achieve high transmission data rate in the shallow water channel.

• Journal of Ubiquitous Convergence Technology
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• v.1 no.1
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• pp.3-8
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• 2007

This paper presents a set of techniques used in a real-time visual surveillance system. The system is implemented on a low-cost embedded DSP platform that is designed to work with stationary video sources. It consists of detection, a tracking and a classification module. The detector uses a statistical method to establish the background model and extract the foreground pixels. These pixels are grouped into blobs which are classified into single person, people in a group and other objects by the dynamic periodicity analysis. The tracking module uses mean shift algorithm to locate the target position. The system aims to control the human density in the surveilled scene and detect what happens abnormally. The major advantage of this system is the real-time capability and it only requires a video stream without other additional sensors. We evaluate the system in the real application, for example monitoring the subway entrance and the building hall, and the results prove the system's superior performance.

• Journal of Ubiquitous Convergence Technology
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• v.1 no.1
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• pp.18-22
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• 2007

Multi-Instance Learning(MIL) performs well to deal with inherently ambiguity of images in multimedia retrieval. In this paper, an effective framework for Contented-Based Image Retrieval(CBIR) with MIL techniques is proposed, the effective mechanism is based on the image segmentation employing improved Mean Shift algorithm, and processes the segmentation results utilizing mathematical morphology, where the goal is to detect the semantic concepts contained in the query. Every sub-image detected is represented as a multiple features vector which is regarded as an instance. Each image is produced to a bag comprised of a flexible number of instances. And we apply a few number of MIL algorithms in this framework to perform the retrieval. Extensive experimental results illustrate the excellent performance in comparison with the existing methods of CBIR with MIL.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2015.07a
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• pp.177-180
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• 2015

본 논문에서는 비디오 영상을 입력 했을 때 특징점 추적을 통한 다수 영상의 고속 스트칭 기법을 제안한다. 빠른 속도로 특징점 추출을 위해서 FAST(Features from Accelerated Segment Test) 기법을 사용한다. 특징점 정합과정은 기존의 방법과는 다른 새로운 방법을 제안한다. Mean shift 를 통해 특징점이 포함된 영역을 추적하여 벡터(vector)를 구한다. 이 벡터를 사용하여 추출한 특징점들을 정합하는데 사용한다. 마지막으로 이상점(outlier)을 제거하기 위해 RANSAC(RANdom Sample Consensus) 기법을 사용한다. 입력된 두 영상의 호모그래피(homography) 변환 행렬을 구하여 하나의 파노라마 영상을 생성한다. 실험을 통해 제안하는 기법이 기존의 기법보다 속도가 향상되는 것을 확인하였다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.2
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• pp.435-440
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• 2011

A touchless user interface system is proposed for real-time mobile devices in this work. The proposed system first recognizes the position of pattern to interact various applications based on the scene taken from mobile camera. Then, the proposed system traces the route of the pattern, which estimates the motion of pattern based on the mean-shift method. Based on this information, we control menu and keypad for the various applications. Differ from other user interface systems, the proposed system provides the new experience to even for the user of low-end mobile without additional hardware. Simulation results demonstrate that the proposed algorithm provides better interaction performances than the conventional method, while achieving real-time user interacting for mobile devices.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.131-134
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• 2011

영상에서 경계선의 추출의 저수준 영상 처리에서 매우 중요하다. 하지만 대다수의 경계선 추출 방법들은 노이즈들의 영역이 많기 때문에 효율적이지 못하고 영상이 서로 다르기 때문에 유연하지 못하다. 본 논문에서는 이러한 문제 해결을 위하여 우선 노이즈 감소 단계를 제시한다. 그리고 점진적인 변화 폭의 히스토그램과 내부 클래스 최소 변이상의 양쪽 임계값들을 자동으로 선택하도록 한다.

• Journal of Sensor Science and Technology
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• v.14 no.5
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• pp.302-307
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• 2005

Precision displacement of less than a few nm resolution was measured in real-time using fiber optic EFPI sensor. The novel method for real-time processing of analyzing EFPI output signal was developed and verified. Linearity in the mean values of interferometric light intensity among adjacent fringes was shown and verified the sinusoidal approximation algorithm that estimates past and coming fringe values. Real-time signal processing program was developed and the intensity signal of the EFPI sensor was transformed to the phase shift with this program. The resolution below $0.36{\sim}8.6$ nm in the displacement range of $0{\sim}300{\mu}m$ was obtained. The nano-positioner with a piezoelectric actuator and the EFPI sensor system was designed and tested. The positioner successfully reached to the desired destination within 1 nm accuracy.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2022.06a
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• pp.186-189
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• 2022

스마트팜 피노믹스 시스템은 재배하는 식물의 성장조건에 맞게 생육 환경을 일정하게 유지하고 관리하는 장치이지만, 그럼에도 불구하고 식물의 질병은 여러 가지 이유로 발생할 수 있다. 본 논문에서는 스마트팜 피노믹스 시스템에서 Mean Shift Segmentation 을 통한 식물의 질병을 자동으로 검출하는 식물 질병 검출 알고리즘을 제안한다. 식물의 질병 정도가 임의의 임계값을 넘을 경우, 해당 식물을 질병의 정도가 심한 식물로 판별하고, 적절한 수확시기를 결정하여 더 나은 상품성을 가진 식물을 재배할 수 있는 방법을 제시한다. 또한 식물의 질병이 급격하게 심해지는 기간을 확인하여 인간의 개입 없이 완전히 자동화된 시스템으로 더욱 세심하고 효율적인 식물 재배를 가능하게 함을 제시한다. 본 논문에서는 아이스버그(양상추)에 대한 재배 환경을 구축하여 생장 기간에 아이스버그에 발생하는 질병인 팁번 현상을 검출하는 실험을 진행하였다. 본 논문에서 제안한 방법은 다른 종류의 다양한 식물에서도 질병 검출이 가능하며, 스마트팜 피노믹스 시스템에서 질병 검출의 자동화를 위한 한 가지 방법으로 활용될 수 있을 것으로 기대된다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.1
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• pp.272-287
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• 2016

Recently, various and effective contrast based salient object detection models to focus on a single target have been proposed. However, there is a lack of research on detection of multiple objects, and also it is a more challenging task than single target process. In the multiple target problem, we are confronted by new difficulties caused by distinct difference between properties of objects. The characteristic of existing models depending on the global maximum distribution of data point would become a drawback for detection of multiple objects. In this paper, by analyzing limitations of the existing methods, we have devised three main processes to detect multiple salient objects. In the first stage, regional features are extracted from over-segmented regions. In the second stage, the regional features are categorized into homogeneous cluster using the mean-shift algorithm with the kernel function having various sizes. In the final stage, we compute saliency scores of the categorized regions using only spatial features without the contrast features, and then all scores are integrated for the final salient regions. In the experimental results, the scheme achieved superior detection accuracy for the SED2 and MSRA-ASD benchmarks with both a higher precision and better recall than state-of-the-art approaches. Especially, given multiple objects having different properties, our model significantly outperforms all existing models.

• Journal of information and communication convergence engineering
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• v.18 no.2
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• pp.88-93
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• 2020

The IEEE 802.11p-based wireless access in vehicular environments (WAVE) [1] communication is a method used exclusively for wireless communication on the road. This technique enables information sharing not only among moving vehicles but also between vehicles and infrastructure [2]. As part of WAVE communication, data is transmitted to and from vehicles in motion; in this case, it is difficult to determine the channel accurately in an outdoor environment owing to the Doppler shift [3]. This paper proposes a new channel estimation scheme for enhancing the reception performance of the IEEE 802.11p-based WAVE system. The proposed technique obtains the initial channel value by estimating the least square in the time domain by inserting a pilot signal for channel estimation into the IEEE 802.11p virtual subcarrier. Subsequently, a least mean square algorithm is applied to the initial channel value to update the estimated channel value. The simulation results obtained using the proposed channel estimation technique confirm its remarkable efficiency.