• Speech Sciences
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• v.12 no.3
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• pp.125-136
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• 2005

Automatic speech recognition is much more difficult in real world. Speech recognition according to SIR (Signal to Interface Ratio) is difficult in situations in which noise of surrounding environment and multi-speaker exists. Therefore, study on main speaker's voice extractions a very important field in speech signal processing in binaural sound. In this paper, we used directional filter and harmonic filter among other existing methods to extract the main speaker's information in binaural sound. The main speaker's voice was extracted using directional filter, and other remaining speaker's information was removed using harmonic filter through main speaker's pitch detection. As a result, voice of the main speaker was enhanced.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.6
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• pp.591-598
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• 2003

A novel transversal filter using triple-coupled-line directional couplers is proposed. Simple design method which uses sinc function for computing coupling coefficients of the proposed transversal filter are also introduced. The frequency characteristics of the proposed filter are seldom degraded by the connecting sections between the cascaded directional couplers while those of the conventional transversal filter are aggravated. Moreover, the less number of the connecting sections and the directional couplers is required in the proposed filter than fer the case of the conventional transversal filter having the same bandwidth. The performance of the proposed transversal filter is verified by measurement and the measured results are compared with the calculated results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.4A
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• pp.345-355
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• 2002

This paper describes a new method of directional filter-based analysis for fingerprint enhancement. Fingerprint cages can be represented by direction field of regular structure of ridge patterns. The dominant directional component of ridge plays a very important role in pre-processing steps of fingerprint image analysis such as ridge's linking and noise removal for minutiae extraction. A directional filter bank analyzes input image into directional subband images and synthesizes them to the perfectly reconstructed image. In this paper, a new fingerprint enhancement algorithm based on a directional filter bank is proposed. The algorithm decomposes the fingerprint image into subband images in the analysis stage, accomplishes an enhance procedure by processing subband images in the enhance stage and synthesizes them to the enhanced image in the synthesis stage.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.8A
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• pp.796-804
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• 2002

This paper presents a new algorithm of fingerprint image analysis and processing using directional filter bank(DFB). The directional components of ridge is very important in pre-processing steps of fingerprint image processing such as image enhancement by directional filtering followed by estimationg the directional image of ridge patterns. The DFB analyzes input image into directional subband images and synthesizes them to the perfectly reconstructed image. In this paper, a new fingerprint processing algorithm using the DFB is proposed. The algorithm decomposes the fingerprint image into directional subband images and performs directional map generation, foreground segmentation, singular points extraction and image enhancement based on local directional energy estimate.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1999.06a
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• pp.29-34
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• 1999

We present a practical method for removing biotches and restoring their mission data. To detect blotches, we employ a robust approach of local analysis of spatiotemporal anisotropic brightness continuity Our approach uses first-order spatiotemporal directional derivatives to select the smoothest direction for each examined pixel, and puts out the incorruption probability that he examined pixel may not be corrupted by blotches. As the restoration filter, were employ a spatiotemporal fuzzy filter whose response is adaptively controlled according to a fuzzy rule defined by the incorruption probability. The fuzzy filter is composed of the two different filter of the identity filter and the spatiotemporal directional-weighted-mean filter, and will put out an intermediate value between the original input brightness and the directional-weighted-mean brightness. We design the fuzzy rule in advance by a standard supervised learning fuzzy rule in advance by a standard supervised learning method. The computer simulations are presented.

• Journal of the Korean Institute of Telematics and Electronics
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• v.22 no.4
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• pp.33-38
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• 1985

By the complemental frequency characteristics of directional filter in passband and stopband the method of isolation between microwave RF and low frequency If is derived. And when this characteristic of microstrip directional filter is applied to MIC balanced mixer from 3.7 to 4.2 GHz, the experimental results of isolation and return loss are more than 20 65 in this band. This balanced mixer with the microstrip coupled directional filter is suitable for the DBS microwave receiver system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.11
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• pp.3145-3162
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• 2023

As an important technology of the internetwork, wireless sensor network technique plays an important role in indoor localization. Non-line-of-sight (NLOS) problem has a large effect on indoor location accuracy. A location algorithm based on improved particle filter and directional probabilistic data association (IPF-DPDA) for WSN is proposed to solve NLOS issue in this paper. Firstly, the improved particle filter is proposed to reduce error of measuring distance. Then the hypothesis test is used to detect whether measurements are in LOS situations or NLOS situations for N different groups. When there are measurements in the validation gate, the corresponding association probabilities are applied to weight retained position estimate to gain final location estimation. We have improved the traditional data association and added directional information on the original basis. If the validation gate has no measured value, we make use of the Kalman prediction value to renew. Finally, simulation and experimental results show that compared with existing methods, the IPF-DPDA performance better.

• Korean Journal of Optics and Photonics
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• v.13 no.5
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• pp.373-376
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• 2002

An asymmetrical directional coupler with two nonidentical fibers has, for the first time, been proposed and analyzed for an EDFA gain flattening filter (GFF). The characteristics of the transmission spectra of the GFFs have been theoretically investigated for the core spacings, the coupling lengths and the fiber parameters of the asymmetrical directional coupler. The analytical results show that an EDFA gain spectrum with flatness of ~7 ㏈ can be flattened to within $\pm$0.75 ㏈ over a bandwidth of 30 nm by using the asymmetrical directional coupler-based GFF.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.10
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• pp.996-1003
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• 2003

There are critical drawbacks in fabricating MMIC transversal filters because the length of the conventional transversal filter structure is much longer than the width. In order to solve this structural problem, a transversal filter using multiple-coupled-line directional couplers which can achieve tight coupling is proposed. The length of the proposed transversal filter can be made short using multiple-coupled-line couplers so that the structure of the proposed filter is applicable to MMIC technology. Because of the dielectric and conductor losses, the excited signal at the input port becomes smaller when it progresses through each directional coupler. Therefore, the strength of the coupled signals at the latter directional couplers becomes smaller than the designed one and this, in turn, gives rise to performance aggravation. A modified coupling coefficient formula to prevent frequency characteristic degradation is introduced. The proposed filter structure and the design method are verified by the calculated result and 3D full-wave analysis.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.11 no.2
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• pp.49-57
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• 2007

In fingerprints, singular regions including core or delta points have different directional characteristics from non-singular regions. Generally, the ridges of singular regions change more abruptly than those of nonsingular areas, thus in order to effectively enhance fingerprint images regardless of region, local ridge curvature information needs to be used. In this paper, we present an improved Directional Filter Bank (DFB)-based fingerprint image enhancement method that effectively takes advantage of such ridge curvature information. The proposed method first decomposes a fingerprint image into 8 directional subbands using the DFB and then classifies the image into background, low curvature, and high curvature regions using the directional energy estimates calculated from the subbands. Thereafter, the weight values for directional subband processing are determined using classification information and directional energy estimates. Finally, the enhanced image is obtained by synthesizing the processed subbands. The experimental results show that the proposed approach is effective in enhancing both singular and non-singular regions.