• 분석과학
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• 제34권2호
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• pp.56-67
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• 2021

Due to the difficulty of grading visualized fingerprints with previously known evaluation methods for the comparison of split fingerprints, a preliminary study was performed with the densitometric image analysis (DIA) method as a potential quantitative and supplementary evaluation method. Each image of inked split fingerprints was divided into 4 zones for analysis. Weekly intra- and inter- analysis by two analysts with three whole fingerprints that were constructed by combining inked split fingerprints showed that the average area values and the ranges of difference fluctuation were not significantly different between strong fingerprints and strong-weak pairs, while they were different in weak fingerprints and weak-weak pairs. In the case of weak fingerprints, the exact acquisition of ridges was difficult and this seemed to influence the results. An additional study is needed for the improved reliability using DIA method with weak fingerprints such as 8 zones division rather than 4 zones. In addition, the analysis results performed by several analysts at different times should be used to improve the reliability of the analysis method further. Based on the above result, it can be judged that utilizing the DIA method as a secondary evaluation method of the existing scoring system would be effective with the additional studies especially on weak fingerprints.

• 시큐리티연구
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• 제61호
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• pp.377-400
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• 2019

사진은 가장 일반적으로 사용되는 현장 기록 방법으로, 증거물 관리의 연속성을 유지하고 현상을 있는 그대로 담아낼 수 있기 때문에 범죄수사 및 각종 사고조사에 널리 이용된다. 최근에는 디지털 카메라가 이용되기 때문에 이미지 조작에 따른 진정성(authenticity) 훼손위험이 있어 이미지 증강에 사용할 수 있는 방법이 제한적인데, 그 중 널리 활용되는 하나가 푸리에 변환 (Fourier transform)이다. 푸리에 변환은 이미지를 주파수 신호로 변환하는 것으로, 본 연구에서는 fast Fourier transform (FFT)을 사용하였다. 본 실험에서는 지문을 규칙적인 패턴을 가진 모눈종이나 또 다른 지문과 겹치게 한 뒤 FFT로 분리하였다. 그리고 원래의 지문과 분리한 지문의 품질을 각각 평가하고 비교하였으며, 두 지문이 같은 지문으로 판정될 수 있는지 검사하였다. 규칙적인 패턴을 가진 배경에 찍힌 지문이나 general pattern끼리 겹쳐진 지문을 분리한 경우 지문 융선이 증강되어 식별에 용이하였다. 하지만 core나 delta와 같이 복잡한 패턴끼리 겹쳐진 지문의 경우 원래의 지문보다 FFT로 분리하여 얻은 지문의 품질이 낮고 식별오류가 많았다. 지문 품질의 저하는 감정관의 신뢰성에 부정적 영향을 미칠 수 있다. 연구의 주요 논점은 지문감정 이외에도 디지털이미지 개선기술이 활용되는 여러 상황에서 참고할 수 있을 것이다.

• 분석과학
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• 제33권2호
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• pp.86-97
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• 2020

Reconstruction and separation of explosive-contaminated overlapping fingerprints constitutes an analytical challenge of high significance in forensic sciences. Laser-induced breakdown spectroscopy (LIBS) allows real-time chemical mapping by detecting the light emissions from laser-induced plasma and can offer powerful means of fingerprint classification based on the chemical components of the sample. During recent years LIBS has been studied one of the spectroscopic techniques with larger capability for forensic sciences. However, despite of the great sensitivity, LIBS suffers from a limited detection due to difficulties in reconstruction of overlapping fingerprints. Here, the authors propose a simple, yet effective, method of using chemical mapping to separate and reconstruct the explosive-contaminated, overlapping fingerprints. A Q-switched Nd:YAG laser system (1064 nm), which allows the laser beam diameter and the area of the ablated crater to be controlled, was used to analyze the chemical compositions of eight samples of explosive-contaminated fingerprints (featuring two sample explosive and four individuals) via the LIBS. Then, the chemical validations were further performed by applying the Raman spectroscopy. The results were subjected to principal component and partial least-squares multivariate analyses, and showed the classification of contaminated fingerprints at higher than 91% accuracy. Robustness and sensitivity tests indicate that the novel method used here is effective for separating and reconstructing the overlapping fingerprints with explosive trace.

• 산업기술연구
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• 제18권
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• pp.295-302
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• 1998

Classification of fingerprints is one of the major subjects on which many researchers have been studying for efficient identification. But fingerprints should be preprocessed in various ways prior to being classified. Factors such as the accuracy and the processing time should be considered in classification of fingerprints. In this paper, we propose a method for classifying fingerprints into several frequent patterns. This method consists of two stages. A fingerprint image is first converted to a skeleton form to find out the center. Then it is identified as a member of one of preclassified pattern by the frequency domain feature. Experiments show that the proposed method is quite useful in classifying fingerprints into typical patterns.

• 분석과학
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• 제35권6호
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• pp.237-241
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• 2022

유리 표면에 부착된 지문을 인화성액체(휘발유, 등유, 경유 혹은 신너)로 오염시킨 후 hexane 혹은 heptane으로 세척하였을 때의 세척 효과를 연구하였다. 이 때 지문은 cyanoacrylate fuming 후 basic yellow 40으로 염색하는 방법으로 가시화하였다. 한 지문을 4등분하여 세척 효과를 비교한 결과 지문 성분이 인화성액체에 용해되어서 융선이 훼손된다는 것을 확인할 수 있었다. 이렇게 인화성액체로 오염된 지문을 hexane이나 heptane으로 세척한 결과 휘발유, 등유 및 신너로 오염되었던 지문은 오염 당시에 융선이 훼손되어서 세척 효과가 나타나지 않았고, 경유로 오염되었던 지문에서만 세척 효과가 나타나 융선의 품질이 향상되었다. 오히려 세척용액으로 사용한 hexane과 heptane은 융선을 훼손시키기 때문에 휘발유, 등유 및 신너로 오염된 지문은 세척과정을 생략하고 바로 증강하는 것이 오히려 낫다는 것을 알 수 있었다. 또한 경유로 오염된 지문을 세척할 때에는 세척용매의 양과 접촉 시간을 최소로 해야 한다는 것을 알 수 있었다.

• 분석과학
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• 제36권6호
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• pp.324-331
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• 2023

젖은 종이류에서는 아미노산 반응 시약으로 지문을 현출할 수 없어 oil red O (ORO)와 같은 지질 염색 시약 또는 physical developer (PD)를 적용해야 한다. 그러나 ORO는 4주 이상 된 오래된 지문에서 효과적이지 않다. 반면 PD는 오래된 지문을 잘 현출하지만 비교적 최근에 남겨진 지문에서는 효과적이지 아니하며, 지문 현출에 오랜 시간이 소요된다는 단점이 있다. 본 연구에서는 이러한 PD의 한계를 해결하기 위해 vacuum metal deposition (VMD)으로 은을 증착한 후 PD를 적용하여(Ag-PD) PD의 반응성을 높이고자 하였고, 이를 ORO, PD로 현출한 지문과 비교하였다. 그 결과, Ag-PD는 2~8주 동안 보관된 젖은 종이에서 ORO, PD보다우수한지문현출력을보였으며 PD의지문현출시간은 90~150 초로 대폭 감소하였다.

• Journal of information and communication convergence engineering
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• 제18권2호
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• pp.132-146
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• 2020

Biometric technologies have become widely available in many different fields. However, biometric technologies using existing physical features such as fingerprints, facial features, irises, and veins must consider forgery and alterations targeting them through fraudulent physical characteristics such as fake fingerprints. Thus, a trend toward next-generation biometric technologies using behavioral biometrics of a living person, such as bio-signals and walking characteristics, has emerged. Accordingly, in this study, we developed a bio-signal authentication algorithm using electrocardiogram (ECG) signals, which are the most uniquely identifiable form of bio-signal available. When using ECG signals with our system, the personal identification and authentication accuracy are approximately 90% during a state of rest. When using fingerprints alone, the equal error rate (EER) is 0.243%; however, when fusing the scores of both the ECG signal and fingerprints, the EER decreases to 0.113% on average. In addition, as a function of detecting a presentation attack on a mobile phone, a method for rejecting a transaction when a fake fingerprint is applied was successfully implemented.

• Journal of Information Processing Systems
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• 제15권1호
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• pp.22-33
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• 2019

This paper introduces an efficient fingerprint matching method based on multiple reference minutiae points. First, we attempt to effectively align two fingerprints by employing multiple reference minutiae points. However, the corresponding minutiae points between two fingerprints are ambiguous since a minutia of one fingerprint can be a match to any minutia of the other fingerprint. Therefore, we introduce a novel method based on linear classification concept to establish minutiae correspondences between two fingerprints. Each minutiae correspondence represents a possible alignment. For each possible alignment, a matching score is computed using minutiae and ridge orientation features and the maximum score is then selected to represent the similarity of the two fingerprints. The proposed method is evaluated using fingerprint databases, FVC2002 and FVC2004. In addition, we compare our approach with two existing methods and find that our approach outperforms them in term of matching accuracy, especially in the case of non-linear distorted fingerprints. Furthermore, the experiments show that our method provides additional advantages in low quality fingerprint images such as inaccurate position, missing minutiae, and spurious extracted minutiae.

• 분석과학
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• 제35권1호
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• pp.1-7
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• 2022

This study suggests a new one-step fluorescent cyanoacylate-fuming method for developing fingerprints by using a CAB mixed with dimethylaminobenzalde (DMAB) and cyanoacylate (CA) in a specific ratio. CAB is prepared by mixing 2.5 % (w/w) DMAB with CA and fumigated at 180 ℃. Under these conditions, developing fingerprints showed the best results. The fuming method using CAB develops latent fingerprints into fluorescence and has a higher sensitivity than CA, and it showed comparable or better contrast to existing fluorescence enhancement methods. It was also applicable on a variety of non-porous surfaces that can be encountered at ordinary times. This method is more useful than conventional fluorescent dyeing methods in that it minimizes damage to fingerprints or samples, makes it easy to manufacture, saves time, and can use existing current equipment as it is.

• 대한의생명과학회지
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• 제16권3호
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• pp.197-200
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• 2010

All citizens over 17 year old living in Korea have to be fingerprinted to obtain a certificate of resident registration. For this reason, human identification through fingerprints has been used actively in crime scene investigation. The fingerprint is so unique that it is one of the most certain ways to identify oneself and it can differentiate between genetically identical twins. Fingerprints gained in crime scene indicate a direction of criminal investigation in conjecturing a suspect. Fingerprints help a reunion of family got scattered for a long time and make it possible to get a personal identification for missing person who met with natural calamity. We developed a new fingerprinting method using safranine O, so as to develop fingerprints on the adhesive tapes and non-porous papers in various physical environments. Results were compared to the preexisting fingerprinting method, the minutiae numbers of fingerprints were greatly increased in our newly developed safranine O fingerprinting method. This newly developed safranine O method showed a quantity and quality comparable to the preexisting fingerprinting method routinely used in these days. In our hands, the safranine O fingerprinting method is another easy and obvious choice when the forensic case sample is available for fingerprints on the adhesive tapes and non-porous papers.