• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.8
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• pp.62-70
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• 1997

In this paper, we presetn a new method to display 3-D image modelled as a sum of 2-D sliced images by expanding the concept of the conventional 2-D optical correlator based on spatial matched filtr to the 3-D region. It is hsown that a arbitrary image can be constructed by an array of the correlation-peaks between pixel-to-pixel and propose the systhesis precedure of 3-D spatial-matched-fjilter using fresnel diffraction equation to display 3-D image in space. It is also shown that the quantization problem is severe when the systehsised filter function is displayed on the conventional LC-SLM. To overcome this problem, anonlinear quantizaton method using the sigmoid function is suggested, and this method can reduce the bias and the loss of high spatial-frequency information, and improve the diffraction efficiency. Finally, the suggested method is tested by computer simulation and then approved by some optical experiments with the conventional LC-SLM.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.1
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• pp.84-91
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• 2008

In this paper, we propose a Sequency domain based BPM-UWB receiver compensating for distortion in the multi-path channel. We give a mathematical derivation for the proposed receiver which exploits a matched filter theory for optimum reception. We also analyze the system performance and present the simulation results that show the performance enhancement of the proposed system.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.1
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• pp.132-144
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• 1997

The rotation-invariant pattern recognition filter using circular harmonic function of the wavelet transforme dsreference image by morlet, mexican-hat, and haar wavelt function is proposed. The rotated reference images, the images sililar to the reference image, and the images which are added by random noise are used for the inpt images, and in case of the input images with random noise, they are applied to the recognition after removing the random noise by the transformed moving average method with proper thresholding value and window size. The proposed optical wavelet circular harmonic matched filter (WCHMF) is a type of the matche dfilter, so that it can be applied to the 4f vander lugt optical correlation system. SNR and discrimination capability of the proposed filter are compared with those of the conventional HF, the POCHF, and the BPOCHF. The proper wavelet function for the reference image used in this paper is achieved by applying morlet, mexican-hat, and harr wavelet function ot the proposed filter, and the proposed filter has good SNR and discrimination capability with rotation-invariance in case of the morlet wavelet function.

• The Journal of the Acoustical Society of Korea
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• v.22 no.2
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• pp.153-161
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• 2003

In this paper, we propose a wavelet-based detection method to identify efficiently the time-delay or multipath channel of ocean acoustic signals due to complex ocean medium and boundary layers. Our proposed method employs wavelet packet transform to analyze the received broadband acoustic signals and applies the matched filter to determine the time region of interest. Also, we present numerical testing that results on both the simulated and real data revealed the efficiency of this method in time-delay estimation and moreover its capability in estimating the time-delay of individual path in multipath channel, in which the arrival patterns are too close to be separated by the matched filter method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.13 no.5
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• pp.400-410
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• 1988

In this paper, a fast synchronization system using SAW TDL matched filter and SAW recirculation loop not only for acquisition but also tracking in the direct sequence spread spectrum communication receiver in case of low SNR was designed and its characteristics were investigated. When signal of 16dB SNR was inputed at the receiver, the PN code of the receiver could be synchronized from the extracted signal for synchronization through SAW TDL matched filter and SAM recirculation loop for 30 recirculations. And the average synchronization time of this system was calculated. From the results, we found that this synchronization system could achieve faster synchronization of PN codes in the receiver under the circumstances of low SNR than that of using only matched filter.

• Journal of the Institute of Convergence Signal Processing
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• v.5 no.4
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• pp.325-332
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• 2004

In this paper, we propose a new DSSS-QPSK baseband modem receiver structure. A general receiver consists of matched filter, do-spreader, and DLL(Delay Locked Loop). In this paper, the matched filter plays a role of the do-spreader using the structure similarities between the matched filter and the de-spreader. As a result of the new receiver architecture, we can reduce the computational expenses and get the simpler receiver structure. This result can be used as an important part in designing the high speed modem. And, through the computer simulation and the experiment with the proposed architecture, we show that the proposed receiver structure yields fast operation speed and simple overall architecture.

• Journal of electromagnetic engineering and science
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• v.4 no.2
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• pp.72-78
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• 2004

In this paper, we evaluate the performance of the digital modulation schemes described in the APCO Project 25 FDMA specifications which can be used for applying the ultra-narrowband technology to the current domestic simple two-way radio systems, and discuss difficulties in the DSP implementation of the systems. We analyze the effect on the systems' BER performance of receiver non-matched filter and frequency-offset between the transmitter and receiver oscillators. And we present a frequency offset compensation method for improving the system performance. The results of performance analysis showed that the CQPSK of APCO Project 25 using non-matched filter degraded the BER by 0.5～1.0 ㏈ comparing with PI/4 DQPSK using matched filter. In the event of 2 % frequency offset, about 1 ㏈ performance loss was produced at the BER of $$10^{-3}TEX>. With the frequency-offset compensation method implemented in the systems using phase recovery scheme of PSK synchronization detection, the performance degradation of about 1.0 ㏈ was occurred at the BER of $$10^{-3}TEX> for 10 % of frequency offset. The proposed method can be used for the improvement of system performance.

• Journal of the Korea Society of Computer and Information
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• v.24 no.6
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• pp.57-65
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• 2019

In this paper, we study on finding the rail space in elevators by analyzing each image captured with CCD camera. We propose a method that applies one-dimensional matched filter to the pixels of a selected search space in the vertical line at a horizontal position and decides the position with the thickness of the space being represented by a black thick line in captured images. The pattern similarity representing how strongly the associated image pixels resemble with the thick line is defined and calculated with respect to each position along the vertical line of pixels. The position and thickness of the line are decided from the point having the maximum in pattern similarity graph. In the experiments of the proposed method under different illuminational conditions, it is observed that all the pattern similarity graphs show similar shape around door area independent of the conditions and the method can effectively detect the rail space if the rails are illuminated with even weak light. The method can be used for real-time embedded systems because of its simple algorithm, in which it is implemented in simple structure of program with small amount of operations in comparison with the conventional approaches using Canny edge detection and Hough transform.

• Proceedings of the KOSOMBE Conference
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• v.1995 no.11
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• pp.109-112
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• 1995

This paper is a study on the detection of the significant point in ECG signal. ECG signal consists of two components; one is high frequency component to be detected and the other is low frequency component to be removed. AR model is appropriate for modelling and removing the low frequency component. AR model coefficients are updated by artificial neural network algorithm. We can remove the background noise(low frequency) by passing through the AR filter. The remaining signals which include high frequency noise are sent to the matched filter to pass only the signal which we want to extract. The template used in matched filter is updated adaptively.

• Journal of Korea Multimedia Society
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• v.21 no.9
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• pp.1052-1061
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• 2018

In this paper, we propose a new algorithm that is robust against the effects of objects that are relatively unaffected by camera motion and can accurately detect camera motion even in high resolution images. First, for more accurate camera motion detection, a global motion filter based on entropy of a motion vector is used to distinguish the background and the object. A block matching algorithm is used to find exact motion vectors. In addition, a matched filter with the angle of the ideal motion vector of each block is used. Motion vectors including 4 kinds of diagonal direction, zoom in, and zoom out are added additionally. The experiment shows that the precision, recall, and accuracy of camera motion detection compared to the recent results is improved by 12.5%, 8.6% and 9.5%, respectively.