• Journal of Broadcast Engineering
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• v.16 no.3
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• pp.501-509
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• 2011

In this paper, we propose an edge profile adaptive bi-directional diffusion interpolation method which consists of shock filter and level set. In recent years many interpolation methods have been proposed but all methods have some degrees of artifacts such as blurring and jaggies. To solve these problems, we adaptively apply shock filter and level set method where shock filter enhances edge along the normal direction and level set method removes jaggies artifact along the tangent direction. After the initial interpolation, weights of shock filter and level set are locally adjusted according to the edge profile. By adaptive coupling shock filter with level set method, the proposed method can remove jaggies artifact and enhance the edge. Experimental results show that the average PSNR and MSSIM of our method are increased, and contour smoothness and edge sharpness are also improved.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.12
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• pp.2529-2531
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• 2009

A simple multimodal fingerprint recognition method based on two types of feature vectors such as minutiae points and directional features is proposed, where Directional Filter Bank (DFB) is used to extract directional features. Experimental results show that the proposed method can effectively combine minutiae- and DFB-based methods and produce a better matching capability in the poor quality fingerprint image.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.2
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• pp.353-359
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• 2006

As for the characteristic of elements for a lot of communication used in light communication systems, it is affected according to structure of directional coupler. We carried out study on a characteristic of the directional coupler which had waveguide structure to have perturbation phenomenon in this paper and ran simulation on the characteristic that we changed structure of directional coupler too, and was got. Confirmation was able to do that it operated with an optical filter, and the directional coupler which added waveguide structure to produce perturbation phenomenon by the results was able to confirm what we adjusted duty ratio of waveguide structure too, and operated with a more excellent optical filter. Through simulation, the case that duty ratio changed than the case that duty ratio of waveguide structure was $50\%$ was able to get an excellent answer characteristic of a -l8dB degree.

• Proceedings of the IEEK Conference
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• 2001.06d
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• pp.25-28
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• 2001

본 논문은 잡음에 의해 열화된 지문영상을 향상시키기 위해 화소가 가지는 다중방향성을 이용하는 방법을 제안한 다. 지문영상은 융선과 골의 규칙적인 배열로 이루어지는데 이러한 융선과 골을 구성하는 화소의 방향성들은 잡음이 가지는 방향성들과는 구별된다 방향성대역 통과 필터뱅크(Directional Filter Bank : DFB)는 입력영상이 가진 일정한 방향성 대역을 통과시켜서 다수개의 부영상들을 생성한다. 본 논문은 DFB를 이용하여 지문영상을 다수개의 특정 방향성을 가진 부영상들로 분해한 다음 이러한 부영상들을 사용하여 지문영상을 개선한다

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.1
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• pp.1-7
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• 1988

A new type broadband channel dropping filter which has a potential use as a millimeter-wave multiplexer has been realized by properly connecting 3-dB directional couplers and bandstop filters. 90\ulcorner3-dB directional couplers have been designed using two nonuniformly coupled dielectric image guides, while bandstop filters with Chebyshev passbands have been designed using dielectric image-guide grating structure. Effective dielectric constant method has been aplied to the image-guide dispersion analysis and to the design of bandstop gratings and 3-dB couplers. Experimental results in excellent agreement with computed responses are demonstrated.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.11C
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• pp.1098-1110
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• 2003

In this paper, we propose a homomorphic wavelet-based MMSE filter with edge detection to restore images degraded by speckle noise. In the proposed method, a noisy image is first transformed into logarithmic domain. Each pixel in the transformed image is then classified into flat and edge regions by applying DIP operator to the image restored by homomorphic directional MMSE filter. Each pixel in flat region is restored by homomorphic wavelet-based MMSE filter. Each pixel in edge region is restored by the weighted sum of the output of homomorphic wavelet-based MMSE filtering and that of homomorphic directional MMSE filtering. The restored image in spatial domain is finally obtained by applying the exponential function to the restored image in logarithmic domain. Experimental results show that the restored images by the proposed method have ISNR improvement of 3.3-4.0 ㏈ and ${\beta}$, a measurement parameter on edge preservation, improvement of 0.0103-0.0126 and superior subjective image quality over those by conventional methods.

• Journal of Industrial Technology
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• v.24 no.A
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• pp.59-65
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• 2004

Personal identification using fingerprints needs much calculational effort. Generally, there are various methods for fingerprint-based identification. In this paper, an identification method is proposed which is based on direction distribution of fingerprint ridges. An 8-directional Gabor filter bank is used for extracting the feature vector from the given fingerprint. Then, it is compared with those of registered fingerprints for matching. This method is simple and fast to implement because it uses the information of ridge directions only. An experiment on 532 fingerprints from NIST database and some other source shows its usefulness.

• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.6
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• pp.833-839
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• 1986

This paper describes the development of a new type of an integrated optical filter using the frequency characteristics of a directly-connected directional coupler with a Rib waveguide. It has been designed for multiplexing and demultiplexing light froups in different wavelength regions. Also, the effects of higher modes, couplings between input waveguides or output waveguides, and dispersion of material are considered.

• ETRI Journal
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• v.25 no.2
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• pp.101-108
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• 2003

This paper proposes an improved vascular pattern extraction algorithm for person verification applications. The proposed direction-based vascular pattern extraction (DBVPE) algorithm is based on the directional information of vascular patterns. It applies two different filters to the input images: row vascular pattern extraction filter (RVPEF) for effective extraction of the abscissa vascular patterns and column vascular pattern extraction filter (CVPEF) for effective extraction of the ordinate vascular patterns. We use the combined output of both filters to obtain the final hand vascular patterns. Unlike the conventional hand vascular pattern extraction algorithm, the directional extraction approach prevents loss of the vascular pattern connectivity. To validate the DBVPE algorithm, we used a prototype system with a DSP processor. The prototype system shows approximately a three-times better false acceptance rate (FAR) than the conventional single filter algorithm.

• Journal of the Semiconductor & Display Technology
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• v.6 no.3
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• pp.55-59
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• 2007

Wavelet Transform is amenable to efficient algorithms. So wavelet transform was adopted many signal processing and communication applications. For example, the wavelet transform was adopted as the transform for JPEG2000. However, Wavelet has weakness about smoothness along the contours and limited directional information. Hence, recently, some new transforms have been introduced to take advantage of this property. So we use to other transform, called contourlet transform in compression. In this paper, we propose a new method for image compression based on the contourlet transform, which has been recently introduced. Contourlet transform has a good result about images with smooth contours. Moreover, Contourlet is feasible multiresolution and multidirection expansion using non-separable filter bank. This treatise shows a good image representation after compressing using contourlet transform.