• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.511-515
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• 1999

The main factor decreasing speech recognition rate is the surrounding noise. To lower the noise effect, we generally used the filter bank at preprocessing stage. But, in this paper, we tried to recognize the 10 numeral numbers using 2-D LPC to extract image feature. At first, we obtained the result of speech-only recognition using 13th-order LPC coefficients and then, for distorted speech recognition results of ‘0’, ‘4’, ‘5’, ‘6’ and 9’, we added image parameters such as 12th-order 2-D LPC coefficients. At each frame, we extracted the 2-D LPC coefficients, and simulated recognizer with two parameters such as speech and image. Finally, for the numbers, such as ‘4’and ‘9’, the better results were obtained.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.6
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• pp.1057-1064
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• 2017

High sensitivity magnetic sensor having foreign metal detection capability is proposed utilizing giant magneto-impedance effect. Strip sensor showed the increasing output voltage when the external magnetic field was applied along with strip from strip grounding point, although the initial DC voltage varied depending on the pointing direction of strip sensor. Proposed sensor was able to eliminate more than half of background noise using active noise filter to achive high sensitivity, and it showed the capability to detect magnetized foreign metal object independent of ambient electro-magnetic noise and earth magnet. In case of ferrous sphere, the metal detection up to 0.8mm diameter was experimentally demonstrated at 5mm distance from strip sensor.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.2
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• pp.258-264
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• 2011

In this paper, we designed a frequency synthesizer with a low phase noise and fast lock time and excellent spurious characteristics using the offset-PLL(Phase Locked Loop) that is used in GSM(Global System for Mobile communications). The proposed frequency synthesizer has low phase noise using three times down conversion and third offset frequency of this synthesizer is created by DDS(Direct Digital Synthesizer) to have high frequency resolution. Also, this synthesizer has fast switching speed using DAC(Digital to Analog Converter). but phase noise degraded due to DAC. we improved performance using the DAC noise filter.

• The Journal of the Acoustical Society of Korea
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• v.41 no.4
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• pp.446-460
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• 2022

In this paper, we propose an algorithm to improve target detection rate degradation due to direct blast in a bi-static sonar systems with high duty cycle using an adaptive filters. It is very important to suppress the direct blast in the aforementioned sonar systems because it has a fatal effect on the actual system operation. In this paper, the performance was evaluated by applying the Normalized Least Mean Square (NLMS) and Recursive Least Square (RLS) algorithms to the simulation and sea experimental data. The beam signals of the target and direct blast bearings were used as the input and desired signals, respectively. By optimizing the difference between the two signals, the direct blast is removed and only the target signal is remained. As a result of evaluating the results of the matched filter in the simulation, it was confirmed that the direct blast was removed to the noise level in both Linear Frequency Modultated (LFM) and Generalized Sinusoidal Frequency Modulated (GSFM), and in the case of GSFM, the target sidelobe decreased by more than 20 dB, thereby improving performance. In the sea experiment, it was confirmed that the LFM reduced the level of the transmitted direct wave by 10 dB, the GSFM reduced the level of the transmitted direct wave by about 4 dB, and the side lobe of the target decreased by about 4 dB, thereby improving the performance.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.36C no.5
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• pp.27-37
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• 1999

A CMOS ReadOut Integrated Circuit (ROlC) for InfraRed Focal Plane Array (IRFPA) detector is presented, which is a key component in uncooled thermal imaging systems. The ROIC reads out signals from $64\times64$ Barium Strontium Titanate (BST) infrared detector array, then outputs pixel signals sequentially after amplifying and noise filtering. Various design requirements and constraints have been considered including impedance matching, low noise, low power dissipation and small detector pitch. For impedance matching between detector and pre~amplifier, a new circuit based on MOS diode structure is devised, which can be easily implemented using standard CMOS process. Also, tunable low pass filter with single~pole is used to suppress high frequency noise. In additions, a clamping circuit is adopted to enhance the signal~to-noise ratio of the readout output signals. The $64\times64$ IRFPA ROIC is designed using $0.65-\mu\textrm{m}$ 2P3M (double poly, tripple metal) N~Well CMOS process. The core part of the chip contains 62,000 devices including transistors, capacitors and resistors on an area of about $6.3-mm\times6.7-mm$.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.4
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• pp.61-67
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• 2017

Low-dose X-ray fluoroscopic image sequences to avoid radiation exposure risk are contaminated by quantum noise. To restore these noisy sequences, we propose a 3D nonlocal means (NLM) filter based on stochastic distancesed can be applied to the denoising of X-ray fluoroscopic image sequences. The stochastic distance is obtained within motion-compensated noise filtering support to remove the Poisson noise. In this paper, motion-adaptive weight which reflected the frame similarity is proposed to restore the noisy sequences without motion artifact. Experimental results including comparisons with conventional algorithms for real X-ray fluoroscopic image sequences show the proposed algorithm has a good performance in both visual and quantitative criteria.

• Journal of Satellite, Information and Communications
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• v.12 no.1
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• pp.64-71
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• 2017

In this paper, Kalman filter and RRWA algorithm are used to estimate the accurate target in IR-UWB (Impulse-Radio Ultra Wideband) radar system, which enables accurate location recognition of indoors and outdoors with low cost and low power consumption. In the signal reflected by the target, unnecessary signals exist in addition to the target signal. We have tried to remove unnecessary signals and to derive accurate target signals and improve performance. The location of the targets is estimated in real time with one transmitting antenna and one receiving antenna. The Kalman filter was used to remove the background noise and the RRWA algorithm was used to remove the reflected signal. In this paper, we think that it will be useful to study the accurate distance estimation and tracking in future target estimation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.7
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• pp.910-916
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• 2021

In modern society, various digital communication equipment is being used due to the influence of the 4th industrial revolution. Accordingly, interest in removing noise generated in a data transmission process is increasing, and research is being conducted to efficiently reconstruct an image. In this paper, we propose a filtering algorithm to remove the AWGN generated in the digital image transmission process. The proposed algorithm classifies pixels with high similarity by selecting regions with similar patterns around the input pixels according to block matching to remove the AWGN that appears strongly in the image. The selected pixel determines the estimated value by applying the weight obtained by the local steering kernel, and obtains the final output by adding or subtracting the input pixel value according to the standard deviation of the center mask. In order to evaluate the proposed algorithm, it was simulated with existing AWGN removal algorithms, and comparative analysis was performed using enlarged images and PSNR.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.1
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• pp.130-136
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• 2017

Recently, as demand of video processor unit rapidly increases, excellent quality of the video has been required. However, generally, video data occurs the quick flame of video due to various external causes in process of acquisition, treatment, and transmission, and major cause of the quick flame of the video is known as the noise. There are various kinds of noise, which are added to the video, AWGN is a typical one. Thus, this thesis suggested algorithm that treats in three methods by scale of the edge through using edge information of local masks. In case that edge pixel is big, it applied spatial weighting according to equation of straight line about direction of edge pixel. In case that edge pixel is middle, it suggested algorithm with spatial weighting filter and average filter, and for the smooth territory, it suggested algorithm that treats with average filter.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.3
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• pp.585-590
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• 2012

Coronary Intervention treatment has become the core that is the test of cardiac catheterization to conduct treatment with Coronary Arteriography. Operators must be careful in Coronary Intervention treatment because the stent is inserted into the point of narrowing of blood vessel. So, the operator must correctly recognize the path of blood vessel to deal with the problems which are damages and ruptures of blood vessel, and there would be some errors of finding the path of blood vessel by bad qualify of the image. Therefore in this paper, median filtering is conducted by preprocessing to evaluate the performance of the effect of noise of the image that affects quality of the image and Fuzzy Edge Extraction Techniques is tested by using Soble Edge Extraction Techniques to compare the performance with The Fuzzy Edge Extraction Techniques. In result, the performance, removing the noise and extracting the signal of Fuzzy Edge Extraction Techniques using median filtering, demonstrates the superiority.