• Smart Media Journal
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• v.1 no.3
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• pp.48-55
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• 2012

In general, background subtraction based methods are used to detect the moving objects in visual tracking applications. In this paper we employed background subtraction based scheme to detect the temporarily stationary objects. We proposed two schemes for stationary object detection and we compare those in terms of detection performance and computational complexity. In the first approach we used single background and in the second approach we used dual backgrounds, generated with different learning rates, in order to detect temporarily stopped object. Finally, we used normalized cross correlation (NCC) based image comparison to monitor and track the detected stationary object in a video scene. The proposed method is robust with partial occlusion, short time fully occlusion and illumination changes, as well as it can operate in real time.

• The Journal of Korea Robotics Society
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• v.2 no.2
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• pp.129-136
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• 2007

This paper introduces a position-based robust visual servoing method which is developed for operation of a human-like robot with two arms. The proposed visual servoing method utilizes SIFT algorithm for object detection and CAMSHIFT algorithm for object tracking. While the conventional CAMSHIFT has been used mainly for object tracking in a 2D image plane, we extend its usage for object tracking in 3D space, by combining the results of CAMSHIFT for two image plane of a stereo camera. This approach shows a robust and dependable result. Once the robot's task is defined based on the extracted 3D information, the robot is commanded to carry out the task. We conduct several position-based visual servoing tasks and compare performances under different conditions. The results show that the proposed visual tracking algorithm is simple but very effective for position-based visual servoing.

• Journal of the Optical Society of Korea
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• v.20 no.3
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• pp.413-426
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• 2016

There has been much advancement in the field of aerial cameras for geographical features with the help of drones, image processing power and computer aided optical programs. In this study, we propose a new optical lens design technique which minimizes the amount of ‘the third order Seidel aberration’ for enhancing MTF. In addition, we suggest a new optical lens design which stabilizes the mass-production yield through R.S.M and has robustness secure through the Taguchi method. Eventually, the image processing algorithm of stereo matching is implemented in order to evaluate whether the proposed lens design result meets adequate specifications for the use of dual aerial photographs or not. This paper provides good guidance for the optical design by development of experiments.

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.2809-2811
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• 1999

In this paper, we develope an algorithm to calculate field inhomogeneity in MR imaging using a dual fast spin echo pulse sequence. Because phase modulation time can be easily modified with this pulse sequence, high resolution image can be obtained and acquisition time can be reduced compared to gradient echo technique. In the case of phase wrapping in field map, phase corrected using image processing technique. We assume the field pattern to be second order polynomial and apply Pseudo-Inverse equation to calculate second order polynomial coefficients. These coefficients can be used for the shimming of the magnetic field.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.747-749
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• 2003

인간은 시각기관을 통해 영상을 읽어 들이고, 그 데이터로부터 대상 물체의 여러 정보를 취득한다. 물체가 놓여져 있는 빛 환경 하에서 반사, 굴절, 흡수, 투과 및 간섭 등과 같은 매우 복잡한 빛 작용의 결과인 영상이 눈에 입력된다. 이 여러 정보 가운데 깊이와 색상 정보는 매우 중요한 인간의 시각 식별 인지 능력이다. 이 논문은 깊이와 색상의 상관관계를 실험을 통해 규명하고자 하였다. 색상 변화는 grey tone으로 한정하였다. 깊이와 색상을 각각 독립변수로 설정한 실험 조건 하에서 디지털 영상신호 데이터를 취득, 분석하였다. 색상을 상수로 처리한 다음, 깊이를 변수로 등간격으로 변화시켜 실험한 후, 변수를 바꾸어 깊이를 상수로 놓고 색상을 다단계로 변화시켜 영상 데이터를 취득하였다. 빛의 조사(照射) 작도는 90도로 일정하게 두어 그림자 효과를 배제하였다. 디지털 영상 입력 과정에서 포함되기 쉬운 노이즈와 떨림, 초점 흐림 등을 전처리로 처리한 후 색도 변화를 분석하였다. 분석 결과, 이미지 속에 내재된 깊이와 색상 정보의 상호 이중적 구조 형태로의 존재를 규명하였다.

• Asian Journal of Atmospheric Environment
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• v.5 no.1
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• pp.8-20
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• 2011

Atmospheric visibility is one of the indicators used to evaluate the status of air quality. Based on a conceptual definition of visibility as the maximum distance at which the outline of the selected target can be recognized, an image analysis technique is introduced here and an algorithm is developed for visibility monitoring. Although there are various measurement techniques, ranging from bulk and precise instruments to naked eye observation techniques, each has their own limitations. In this study, a series of image analysis techniques were introduced and examined for in-situ application. An imaging system was built up using a digital camera and was installed on the study sites in Incheon and Seoul separately. Visual range was also monitored by using a dual technology visibility sensor in Incheon and transmissometer in Seoul simultaneously. The Sobel mask filter was applied to detect the edge lines of objects by extracting the high frequency from the digital image. The root mean square (RMS) index of variation among the pixels in the image was substantially correlated with the visual ranges in Incheon and Seoul with correlations of $R^2$=0.88 and $R^2$=0.71, respectively. The regression line equations between the visual range and the RMS index in Incheon and Seoul were VR=$2.36e^{0.46{\times}(RMS)}$ and VR=$3.18e^{0.15{\times}(RMS)}$, respectively. It was also confirmed that the fine particles ($PM_{2.5}$) have more impacts to the impairment of visibility than coarse particles.

• Journal of IKEEE
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• v.27 no.4
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• pp.494-500
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• 2023

Image processing is currently used in various fields. Among them, autonomous vehicles, medical image processing, and robot control require fast image processing response speeds. To fulfill this requirement, hardware design for real-time processing is being actively researched. In addition to the size of the input image, the hardware processing speed is affected by the size of the inactive video periods that separate lines and frames in the image. In this paper, we design three different scaler structures based on the type of line memories, which is closely related to the inactive video periods. The structures are designed in hardware using the Verilog standard language, and synthesized into logic circuits in a field programmable gate array environment using Xilinx Vivado 2023.1. The synthesized results are used for frame rate analysis while comparing standard image sizes that can be processed in real time.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.11
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• pp.2541-2547
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• 2010

In this paper, we propose a design technique which replaces logic transistors of 1.2V with medium-voltage transistors of 3.3V having small off-leakage current in repetitive block circuits where speed is not an issue, to implement a low-power eFuse OTP memory IP in the stand-by state. In addition, we use dual-port eFuse cells reducing operational current dissipation by reducing capacitances parasitic to RWL (Read word-line) and BL (Bit-line) in the read mode. Furthermore, we propose an equivalent circuit for simulating program power injected to an eFuse from a program voltage. The layout size of the designed 512-bit eFuse OTP memory IP with a 90nm CMOS image sensor process is $342{\mu}m{\times}236{\mu}m$. It is confirmed by measurement experiments on 42 samples with a program voltage of 5V that we get a good result having 97.6 percent of program yield. Also, the minimal operational supply voltage is measured well to be 0.9V.

• Journal of Astronomy and Space Sciences
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• v.28 no.1
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• pp.55-62
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• 2011

The precise orbit determination (POD) of low earth orbiter (LEO) has complied with its required positioning accuracy by the double-differencing of observations between International GNSS Service (IGS) and LEO to eliminate the common clock error of the global positioning system (GPS) satellites and receiver. Using this method, we also have achieved the 1 m positioning accuracy of Korea Multi-Purpose Satellite (KOMPSAT)-2. However double-differencing POD has huge load of processing the global network of lots of ground stations because LEO turns around the Earth with rapid velocity. And both the centimeter accuracy and the near real time (NRT) processing have been needed in the LEO POD applications--atmospheric sounding or urgent image processing--as well as the surveying. An alternative to differential GPS for high accuracy NRT POD is precise point positioning (PPP) to use measurements from one satellite receiver only, to replace the broadcast navigation message with precise post processed values from IGS, and to have phase measurements of dual frequency GPS receiver. PPP can obtain positioning accuracy comparable to that of differential positioning. KOMPSAT-5 has a precise dual frequency GPS flight receiver (integrated GPS and occultation receiver, IGOR) to satisfy the accuracy requirements of 20 cm positioning accuracy for highly precise synthetic aperture radar image processing and to collect GPS radio occultation measurements for atmospheric sounding. In this paper we obtained about 3-5 cm positioning accuracies using the real GPS data of the Gravity Recover and Climate Experiment (GRACE) satellites loaded the Blackjack receiver, a predecessor of IGOR. And it is important to reduce the latency of orbit determination processing in the NRT POD. This latency is determined as the volume of GPS measurements. Thus changing the sampling intervals, we show their latency to able to reduce without the precision degradation as the assessment of their precision.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.2
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• pp.193-199
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• 2008

In this paper, it is proposed the implementation of face authentication system based on real-time image processing. We described the process implementing the two steps for real-time face authentication system. At first face detection steps, we describe the face detection by using feature of wavelet transform, LoG operator and hausdorff distance matching. In the second step we describe the new dual-line principal component analysis(PCA) for real-time face recognition. It is combines horizontal line to vertical line so as to accept local changes of PCA. The proposed system is affected a little by the video size and resolution. And then simulation results confirm the effectiveness of out system and demonstrate its superiority to other conventional algorithm. Finally, the possibility of performance evaluation and real-time processing was confirmed through the implementation of face authentication system.