http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
A novel touchless fingerprint acquisition device for 5 fingerprints
Kyoungtaek Choi,Heeseung Choi,Donghyun Noh,Jaihie Kim 대한전자공학회 2008 ICEIC:International Conference on Electronics, Inf Vol.1 No.1
This paper introduces a novel touchless fingerprint acquisition device for five fingerprints. The device consists of a single CCD camera, a mirror, two LED arrays and a rotational gear. Unlike the conventional touchbased fingerprint sensors, the device acquires a deformation free fingerprint image. Also the device captures five fingerprint images at once. In this paper, the device was evaluated in three ways: the area of valid regions, the rolling degree of a finger, the degree of focus.
Fingerprint Image Mosaicking by Recursive Ridge Mapping
Kyoungtaek Choi,Heeseung Choi,Sangyoun Lee,Jaihie Kim Institute of Electrical and Electronics Engineers 2007 IEEE Transactions on Cybernetics Vol.37 No.5
<P>To obtain a large fingerprint image from several small partial images, mosaicking of fingerprint images has been recently researched. However, existing approaches cannot provide accurate transformations for mosaics when it comes to aligning images because of the plastic distortion that may occur due to the nonuniform contact between a finger and a sensor or the deficiency of the correspondences in the images. In this paper, we propose a new scheme for mosaicking fingerprint images, which iteratively matches ridges to overcome the deficiency of the correspondences and compensates for the amount of plastic distortion between two partial images by using a thin-plate spline model. The proposed method also effectively eliminates erroneous correspondences and decides how well the transformation is estimated by calculating the registration error with a normalized distance map. The proposed method consists of three phases: feature extraction, transform estimation, and mosaicking. Transform is initially estimated with matched minutia and the ridges attached to them. Unpaired ridges in the overlapping area between two images are iteratively matched by minimizing the registration error, which consists of the ridge matching error and the inverse consistency error. During the estimation, erroneous correspondences are eliminated by considering the geometric relationship between the correspondences and checking if the registration error is minimized or not. In our experiments, the proposed method was compared with three existing methods in terms of registration accuracy, image quality, minutia extraction rate, processing time, reject to fuse rate, and verification performance. The average registration error of the proposed method was less than three pixels, and the maximum error was not more than seven pixels. In a verification test, the equal error rate was reduced from 10% to 2.7% when five images were combined by our proposed method. The proposed method was superior to other compared methods in terms of registration accuracy, image quality, minutia extraction rate, and verification.</P>
최경택(Kyoungtaek Choi),최희승(Heeseung Choi),김재희(Jaihie Kim) 대한전자공학회 2007 대한전자공학회 학술대회 Vol.2007 No.7
This paper proposes an system to generate rolled-equivalent fingerprints by mosaicking sequential images captured by an touch less device. To capture rolled-equivalent fingerprints, previous works use multiple cameras. However, the method in this paper captures sequential fingerprint images with a single camera and mosaic the images by estimating the transform between images through optical flow.
Mosaicing Touchless and Mirror-Reflected Fingerprint Images
Heeseung Choi,Kyoungtaek Choi,Jaihie Kim IEEE 2010 IEEE transactions on information forensics and sec Vol.5 No.1
<P>Touchless fingerprint sensing technologies have been explored to solve problems in touch-based sensing techniques because they do not require any contact between a sensor and a finger. While they can solve problems caused by the contact of a finger, other difficulties emerge such as a view difference problem and a limited usable area due to perspective distortion. In order to overcome these difficulties, we propose a new touchless fingerprint sensing device capturing three different views at one time and a method for mosaicing these view-different images. The device is composed of a single camera and two planar mirrors reflecting side views of a finger, and it is an alternative to expensive multiple-camera-based systems. The mosaic method can composite the multiple view images by using the thin plate spline model to expand the usable area of a fingerprint image. In particular, to reduce the affect of perspective distortion, we select the regions in each view by minimizing the ridge interval variations in a final mosaiced image. Results are promising as our experiments show that mosaiced images offer 29% more true minutiae and 28% larger good quality area than one-view, unmosaiced images. Also, when the side-view images are matched to the mosaiced images, it gives more matched minutiae than matching with one-view frontal images. We expect that the proposed method can reduce the view difference problem and increase the usable area of a touchless fingerprint image. Furthermore, the proposed method can be applied to other biometric applications requiring a large template for recognition.</P>
Biometric System에서의 Privacy 보호 기술
최경택(Kyoungtaek Choi),박강령(Kang Ryoung Park),김재희(Jaihie Kim) 한국정보보호학회 2005 情報保護學會誌 Vol.15 No.6
본 논문은 현재 생체인식에서의 큰 문제로 대두되고 있는 개인 정보(Privacy) 보호문제를 해결하기 위한 방법들을 소개하고 있다. 이를 위해서는 여러 가지 기술이 사용되는데, 우선 생체정보가 도난되었을 경우 그 피해를 최소화하기 위해 원래의 생체정보를 저장하는 것이 아니라 변환된 생체정보를 저장하고 사용하는 생체정보 변환 기술을 소개한다. 또한 원래의 생체정보가 유출되어 이를 이용해 위조 생체 등을 만들어 공격할 경우를 대비할 수 있는 위조 생체 검출 기술을 소개하며, 생체정보의 유출된 출처를 찾기 위해 생체정보에 소유권 등을 표시하는 데이터 은닉 기법도 소개한다. 이 외에 생체정보를 이용하여 일반적인 암호화 알고리즘에 사용되는 키를 은닉하고 생체정보를 통해 인증된 사용자에 한하여 키를 사용하도록 하는 방법도 소개한다. 끝으로 이러한 개인 정보 보호 기술들을 이용하여 생체인식 시스템의 보안성을 향상시키는 방법에 대하여 논의한다.