• The Journal of Korean Institute of Next Generation Computing
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• v.15 no.3
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• pp.25-30
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• 2019

Magnetic sensors have the disadvantage that their vector values differ depending on the direction. In this paper, we propose a magnetic vector calibration method for geomagnetic-based indoor localization estimates. The fingerprinting technique used in geomagnetic-based indoor localization the position by matching the magnetic field map and the magnetic sensor value. However, since the moving direction of the current user may be different from the moving direction of the person who creates the magnetic field map at the collection time, the sampled magnetic vector may have different values from the vector values recorded in the field map. This may substantially lower the positioning accuracy. To avoid this problem, the existing studies use only the magnitude of magnetic vector, but this reduces the uniqueness of the fingerprint, which may also degrade the positioning accuracy. In this paper we propose a vector calibration algorithm which can adjust the sampled magnetic vector values to the vector direction of the magnetic field map by using the parametric equation of a circle. This can minimize the inaccuracy caused by the direction mismatch.

• Journal of Sensor Science and Technology
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• v.14 no.1
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• pp.28-32
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• 2005

In this paper, a CMOS integrated detection circuit for capacitive type fingerprint sensor signal processing is described. We designed a detection circuit of charge-sharing sensing scheme. The proposed detection circuit increases the voltage difference between a ridge and valley. The test chip is composed of $160{\times}192$ array sensing cells (12 by $12.7{\;}mm^{2}$). The chip was fabricated on a 0.35 m standard CMOS process. Measured difference voltage between a ridge and valley was 0.95 V.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.8 no.6
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• pp.507-514
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• 2015

The Internet of Things era is approaching where all the things are equipped with smart sensors and communicate through internet. The three core technologies of the Internet of Things are 'detection technology' to get information from things and the environment, 'wired and wireless communications and network infrastructure skills' that support to connect things to the internet, and 'service interface technology' that processes the information appropriate to various services. Smart sensor application can expand to smartphone, smart cars, smart home systems, wearable electronic devices, telemedicine systems, and environmental monitoring systems, etc. In particular, technologies that mimic the five human senses. This study reviews the biological principles of the human senses and the principles of operation, research & development status, technology trends and market analysis of the sensors.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.231-232
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• 2007

This paper introduce a new touchless fingerprint sensor. Two mirrors are used to capture the side fingerprint images which cannot detectable using a single camera. We also propose the techniques which can solve the image contrast, nonuniform illumination, DOF(Depth of Field) problems. This new sensor leads to bringing new challenges in the field of fingerprint recognition.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.1464-1466
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• 2015

개인 인증을 위한 바이오인식 방법으로 홍채, 지문, 정맥 인식 등이 널리 사용되고 있다. 하지만 별도의 센서가 필요한 방법들이므로 스마트폰에서 활용하기에 적절하지 않다. 본 논문에서는 엄지손가락 특징을 이용한 새로운 바이오 인식방법을 제안한다. 엄지손가락을 이용한 바이오 인식 방법은 손가락을 촬영하여 영상정보를 획득하는 단계, 영상의 크기와 방향, 밝기를 정규화 하는 단계, 영상 정보로부터 손가락 경계, 손톱 모양, 마디 주름 등의 특징을 검출하는 단계를 포함한다. 제안하는 방법은 카메라가 장착된 스마트기기에서 별도의 센서 추가 없이 개인 인증을 위한 방법으로 활용될 수 있을 것으로 기대된다.

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.1
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• pp.30-36
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• 2016

Recently, digital doorlock systems have been employing biometric recognition and smartphone as personal authentification means. The performance of a digital doorlock system is determined by the two conflicting indices such as security and convenience. This paper proposes and implements one grip based doorpull shaped doorlock systems using fingerprint and touch sensor grip pattern. The proposed system sequentially performs fingerprint recognition and grip pattern identification when a user grips the doorpull in order to open the door. This method so called 'One Grip' is considered to enhance security while maintaining users' convenience. We expect the proposed method can solve the phone missing problem encountered in developing smart doorlock systems based on smartphones.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.2
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• pp.89-98
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• 2004

In this paper, we implement a digital holographic security card system that combines digital holographic memory using random phase encoded reference beams with electrical biometrics. Digitally encoded data including a document, a picture of face, and a fingerprint are recorded by multiplexing of holographic memory. A random phase mask encoding reference beams are used as a decoded key to protect illegal counterfeit. As a result, we can achieve a raw BER of 3.6${\times}$10-4 and shift selectivity of 4${\mu}{\textrm}{m}$ using the 2D random phase mask. Also, we develop a recording pattern and image processing which are suitable for a low cost reader without a position sensing photo-detector for real time data extraction and remove danger of fraud from unauthorized person by comparing the reconstructed holographic data with the live fingerprint data.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.12 no.2
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• pp.101-110
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• 2002

The purpose of this research is to establish Korean standards of best practice and common criteria for testing and evaluating the performance of biometric recognition systems. First of all, research activities in leading countries such as USA, Great Britain and Germany have been studied and analyzed. Then, the standards of best practice and common criteria are proposed in the aspects of sensors, algorithms, and application systems. The results of this work will be utilized fur test and evaluation of commercial biometric products by KISA and provided to private industries for their own evaluation of products.

• Proceedings of the Korean Society of Computer Information Conference
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• 2018.01a
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• pp.185-186
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• 2018

기존의 재활치료기구는 부피가 크고 고비용으로 재활치료센터 운영시간에 맞춰 통원하며 이용해야 하는 불편함이 있었다. 이러한 불편함을 해소하기 위해 제안하는 디지털 서보모터 재활 보조기구는 사용자의 상태에 맞게 전문가와 상의하여 구동수치와 손 안쪽의 와이어의 길이를 수정 한 후 사용하는 것을 원칙으로 사용자가 손가락 끝(지문)에 부착된 감압센서를 누르는 강도와 힘의 유지 유무에 따라 손가락을 굽히거나 펴는 행위를 훈련 할 수 있도록 한 재활치료기구이다. 본 논문의 구현결과는 향후 프로토타입을 보완하여 출력과 운용 방법을 기존과 달리 한다면 다양한 재활기구에 응용될 수 있을 것으로 사료된다.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10b
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• pp.313-318
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• 2007

위치기반서비스에서 사용자의 정확한 위치가 요구되면서 측위와 추적에 대한 연구가 활발히 진행되고 있다. 측위 방법에는 위성기반 방법[1, 2], 로컬네트워크기반 방법[3-6], 센서기반 방법[1, 7, 8, 9]등이 있다. 본 연구에서는 로컬네트워크 중 WLAN (Wireless Local Area Network) 환경의 옥내에서 사용자의 위치를 추적하는 기존의 방법의 정확성을 제고하는 방안을 제안한다. 제안하는 방법은 WLAN 환경에서 RSS를 측정하여 K-NN방식으로 현재 위치를 판단한 다음, 칼만필터를 사용하여 사용자의 위치와 이동경로를 예측한다는 점에서 기존의 방법과 비슷하다. 제안하는 방법의 특징은 도면 정보를 이용하는 것이다. 제안하는 방법은 도면정보로부터 갈림길 영역을 파악하고, 갈림길 영역에서는 측정치에 가중치를 두고 갈림길이 아닌 지역에서는 시스템 모델에 가중치를 두도록 파라메타의 값을 조절한다. 제안하는 방법의 효율성을 실험적으로 증명하기 위한 실험 결과와 분석 내용도 제시한다.