• 전자공학회논문지B
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• 제33B권7호
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• pp.138-146
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• 1996

In this paper, w epropose a new mehtod to represent the shape and to recognize the object. The shape description and the matching is implemented by using the distance transform on the morphological skeleton. The employed distance transform is the chamfer (3,4) distance transform, because the chamfer distance transform (CDT) has an approximate value to the euclidean distance. The 2-D object can be represented by means of the distribution of the distance transform on the morphological skeleton, the number of skeletons, the sum of the CDT, and the other features are employed as the mtching parameters. The matching method has the invariant features (rotation, translation, and scaling), and then the method is used effectively for recognizing the differently-posed objects and/or marks of the different shape and size.

• 한국지능시스템학회논문지
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• 제13권3호
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• pp.281-286
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• 2003

웨이블릿 변환(Wavelet Transform)은 공간-주파수 영역에서 신호의 국소특성을 효율적으로 구현할 수 있다 하지만, 웨이블릿 변환을 패턴 인식을 위한 특징 추출에 적용할 경우, 입력 신호의 위치 이동에 따라 추출된 특징 값이 변화하게 되어 인식률이 낮아지는 결함이 있다. 본 논문에서는 웨이블릿 변환을 패턴 인식에 적용할 경우 발생하는 입력 신호의 위치 이동에 따른 문제점을 보완하여 노이즈에 강인한 홍채인식 알고리즘을 제안한다. 실험을 통하여 제안한 알고리즘의 우수성을 보여 준다.

• Journal of Information Processing Systems
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• 제8권1호
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• pp.85-100
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• 2012

The Hartley transform based feature extraction method is proposed for fingerprint matching. Hartley transform is applied on a smaller region that has been cropped around the core point. The performance of this proposed method is evaluated based on the standard database of Bologna University and the database of the FVC2002. We used the city block distance to compute the similarity between the test fingerprint and database fingerprint image. The results obtained are compared with the discrete wavelet transform (DWT) based method. The experimental results show that, the proposed method reduces the false acceptance rate (FAR) from 21.48% to 16.74 % based on the database of Bologna University and from 31.29% to 28.69% based on the FVC2002 database.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 D
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• pp.2620-2623
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• 2000

The standard approach consists of using correlation of orthogonal functions in digital filtering, such as well-known FFT(Fast Fourier Transform) and FWT(Fast Walsh Transform). But it needs much calculations, multiplications and additions. The calculation amount is m $log_2m$ in the general case. Therefore, this requires high speed processors to calculate in real time, which can calculate floating point. This study developed improved fast Walsh transform based on dyadic-ordered fast Walsh transform, then regenerated signal flow graph of improved fast Walsh transform, and used it for digital filtering, and then measured fundamental frequency and harmonics for current and voltage signals of power system.

• 대한전자공학회논문지
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• 제24권5호
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• pp.905-913
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• 1987

This paper presents a speaker dependent isolated digit recognition algorithm using the Mellin transform. Since the Mellin transform converts a scale information into a phase information, attempts have been made to utilize this scale invariance property of the Mellin transform in order to alleviate a time-normalization procedure required for a speech recognition. It has been found that good results can be obtained by taking the Mellin transform to the features such as a ZCR, log energy, normalized autocorrelation coefficients, first predictor coefficient and normalized prediction error. We employed a difference function for evaluating a similarity between two patterns. When the proposed algorithm was tested on Korean digit words, a recognition rate of 83.3% was obtained. The recognition accuracy is not compatible with the other technique such as LPC distance however, it is believed that the Mellin transform can effectively perform the time-normalization processing for the speech recognition.

• 항공우주기술
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• 제9권1호
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• pp.98-105
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• 2010

고속푸리에변환(Fast Fourier Transform)은 이산푸리에변환(Discrete Fourier Transform)의 주기적으로 반복되는 연산을 생략하여 그 속도를 향상시킨 연산방법이다. Radix-2 FFT는 그 정의에 따라 함수 재귀호출에 의해 구현될 수 있는데 이 방법은 스택복사 과정의 시간소모 때문에 고속동작이 어렵게 된다. 이를 극복하기 위해 신호점을 연산순서에 맞게 미리 재배열하고 배열된 신호점을 나비연산하는 방법으로 고속연산을 구현할 수 있다. 이 논문은 신호점 재배열 방법에 의한 Radix-2 FFT의 고속연산에 착안하여 Radix-3 FFT에 신호점 재배열 방식을 적용해 보고 그 타당성에 관해 고찰하였다.

• 대한화학회지
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• 제37권4호
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• pp.371-377
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• 1993

불안정한 분자의 방출분광학에 상요이 가능하도록 Fourier Transform 분광기를 변형시켰다. 불안정한 분자 라디칼 $CH_3S$는 고전압 직류 방전에 의한 supersonic expansion 속에서 jet 형태의 흐름으로 생성되었다. Supersonic expansion에 의하여 냉각된 라디칼의 형광 스펙트럼은 Fourier Transform UV/VIS 분광기에 의해서 얻어졌다. 스펙트럼의 signal/noise 비율은 증가하였으며, 분자 라디칼 $CH_3S$의 회전구조도 명확하게 볼 수 있었다.

• 전기학회논문지
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• 제61권5호
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• pp.657-663
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• 2012

Recently, by increasing of devices which are sensitive to power quality, the deterioration of power quality has been accelerated. For this reason, the social and economic losses are increased. So not only correct measurement and evaluation, but also countermeasure for improvement of power quality is surely necessary for both electric power supplier and consumer. In this paper, the discrimination algorithm for events and variation occurred in distribution systems using S-transform is proposed. Firstly, we review for events and variations that occur in distribution system. Next, we simulate events and variations on various conditions using ElectroMagnetic Transient Program(EMTP). For the simulation, the IEEE 13 Node Test Feeder and KEPCO's distribution system is modeled. Finally, for the analysis, a modified wavelet transform known as S-transform is adopted to find out the characteristics of each events and variations.

• Nuclear Engineering and Technology
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• 제39권3호
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• pp.221-230
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• 2007

Wavelet theory was applied to detect a singularity in a reactor power signal. Compared to Fourier transform, wavelet transform has localization properties in space and frequency. Therefore, using wavelet transform after de-noising, singular points can easily be found. To test this theory, reactor power signals were generated using the HANARO(a Korean multi-purpose research reactor) dynamics model consisting of 39 nonlinear differential equations contaminated with Gaussian noise. Wavelet transform decomposition and de-noising procedures were applied to these signals. It was possible to detect singular events such as a sudden reactivity change and abrupt intrinsic property changes. Thus, this method could be profitably utilized in a real-time system for automatic event recognition(e.g., reactor condition monitoring).

• Journal of Information Processing Systems
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• 제13권5호
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• pp.1331-1344
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• 2017

In this paper, data hiding algorithm using Discrete Wavelet Transform (DWT) and Arnold Transform is proposed. The secret data is scrambled using Arnold Transform to make it secure. Wavelet subbands of a cover image are obtained using DWT. The scrambled secret data is embedded into significant wavelet coefficients of subbands of a cover image. The proposed algorithm is robust to a variety of attacks like JPEG and JPEG2000 compression, image cropping and median filtering. Experimental results show that the PSNR of the composite image is 1.05 dB higher than the PSNR of existing algorithms and capacity is 25% higher than the capacity of existing algorithms.