• Korean Journal of Optics and Photonics
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• v.13 no.6
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• pp.493-500
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• 2002

Fingerprint recognition is concerned with fingerprint acquisition and matching. Our research was focused on a fingerprint matching method using an inkless fingerprint input sensor at the fingerprint acquisition step. Since an inkless fingerprint sensor produces a digital-image-processed fingerprint image, we did not consider noise that can happen while acquiring the fingerprint. And making the user attempt fingerprint input as random, we considered image distortion that translation and rotation are included as complex. NJTC algorithm is used for fingerprint identification and verification. The method to find the center of the fingerprint is added in the NJTC algorithm to supplement discrimination of fingerprint recognition. From this center point, we decided the optimum cropping size for effective matching with pixels and demonstrated that the proposed method has high discrimination and high efficiency.

• Journal of Information Processing Systems
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• v.19 no.6
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• pp.756-766
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• 2023

To effectively track the illegal use of digital images and maintain the security of digital image communication on the Internet, this paper proposes a reversible multipurpose image watermarking algorithm based on a deep residual network (ResNet) and perceptual hashing (also called MWR). The algorithm first combines perceptual image hashing to generate a digital fingerprint that depends on the user's identity information and image characteristics. Then it embeds the removable visible watermark and digital fingerprint in two different regions of the orthogonal separation of the image. The embedding strength of the digital fingerprint is computed using ResNet. Because of the embedding of the removable visible watermark, the conflict between the copyright notice and the user's browsing is balanced. Moreover, image authentication and traitor tracking are realized through digital fingerprint insertion. The experiments show that the scheme has good visual transparency and watermark visibility. The use of chaotic mapping in the visible watermark insertion process enhances the security of the multipurpose watermark scheme, and unauthorized users without correct keys cannot effectively remove the visible watermark.

• Journal of the Optical Society of Korea
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• v.13 no.4
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• pp.445-450
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• 2009

Fingerprint recognition using a joint transform correlator (JTC) is the most well-known technology among optical fingerprint recognition methods. The JTC method optically compares the reference fingerprint image with the sample fingerprint image then examines match or non-match by acquiring a correlation peak. In contrast to the JTC method, this paper presents a new method to examine fingerprint recognition by producing a computer generated hologram (CGH) of those two fingerprint images and directly comparing them. As a result, we present some parameters to show that fingerprint recognition capability of the CGH direct comparison method is superior to that of the JTC method.

• The Journal of the Korea Contents Association
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• v.17 no.6
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• pp.287-295
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• 2017

This study is aimed at observing effects of fingerprint image quality on various photographing conditions in the aspect of resolution. Discrimination between two friction ridges plays an important role in the value of fingerprint image, and it can be confirmed with quantification of pixels of boundary region which is existing between two friction ridges. In this study, several factors were estimated with same fingerprint image using Adobe photoshop CS 6 for analysis: changes of image quality by ISO, movement when photographing, and photographers' experience and skill. Consequently, there was no significant change of image quality by ISO. Furthermore, there was no significant difference in the hand-held images between crime scene investigators and laymen, yet there was significant difference between hand-held images and images using tripod in the aspect of resolution. This study shows that using tripod is very important in forensic fingerprint photography through empirical methods.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.9
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• pp.887-893
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• 2012

In this paper, we propose a new approach to extract directional features based on directional patterns of each region in fingerprint images. The proposed approach computes the center of gravity to extract features from fingerprint images of various shapes. According to it, we divide a fingerprint image into four regions and compute the directional values of each region. To extract directional features of each region from a fingerprint image, we spilt direction values of ridges in a region into 18 classes and compute frequency distribution of each region. Through the result of our experiment using FVC2002 DB database acquired by electronic devices, we show that directional features are effectively extracted from various fingerprint images of exceptional inputs which lost all or part of singularities. To verify the performance of the proposed approach, we explained the process to model Arch, Left, Right and Whorl class using the extracted directional features of four regions and analyzed the classification result.

• Proceedings of the IEEK Conference
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• 2003.11a
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• pp.297-300
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• 2003

In this paper, fingerprint minutiae mosaicking algorithm using minutiae of fingerprint is proposed. First, minutiae map is generated from minutiae of fingerprint and minutiae constellation is generated from fingerprint minutiae map. Minutiae constellation is constellation-shaped structure generated from Voronoi Diagram and Delaunay Triangulation using information of minutiae. Secondly, common region is detected by similarity of minutiae constellation of fingerprint minutiae map and minutiae map of individual fingerprint image is composed. Consequently composite minutiae map by mosaicking of fingerprint minutiae improve the performance of the fingerprint matching system.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.3
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• pp.23-30
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• 2010

Compression techniques can be applied to large-scale fingerprint systems to store or transmit fingerprint data efficiently. In this paper, we investigate the effects of FBI WSQ fingerprint image compression on the performance of a fingerprint verification system using multiple linear regressions. We propose a maximum compression using fingerprint image quality score. Based on the experiments, we can confirm that the proposed approach can compress the fingerprint images up to 3 times more than the fixed compression ratio without significant degradation of the verification accuracy.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.11 no.2
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• pp.49-57
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• 2007

In fingerprints, singular regions including core or delta points have different directional characteristics from non-singular regions. Generally, the ridges of singular regions change more abruptly than those of nonsingular areas, thus in order to effectively enhance fingerprint images regardless of region, local ridge curvature information needs to be used. In this paper, we present an improved Directional Filter Bank (DFB)-based fingerprint image enhancement method that effectively takes advantage of such ridge curvature information. The proposed method first decomposes a fingerprint image into 8 directional subbands using the DFB and then classifies the image into background, low curvature, and high curvature regions using the directional energy estimates calculated from the subbands. Thereafter, the weight values for directional subband processing are determined using classification information and directional energy estimates. Finally, the enhanced image is obtained by synthesizing the processed subbands. The experimental results show that the proposed approach is effective in enhancing both singular and non-singular regions.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.4
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• pp.1066-1071
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• 1998

This paper aims to examine the relationship between the directional characteristics and the quality for fingerprint image as preprocessing stage for adative image enchancement. In order to do that, we transformed the original images into directional images and set up the subimage size of 16, 32, 64 and the direction of 1, 2, 3, 4. Then we extracted the accumulated directional value as the measurement of quality for fingerprint images. By using the clustering algirthm, we performed an analytic experiemnt with the result. Finally, we could extract the optimal subimage size and directional characteristics of fingerprint image.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.961-962
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• 2008

This paper proposes a touchless fingerprint acquisition device for five fingerprints. In conventional devices, they are focused for taking 1 touchless fingerprint image. But this device is taking 5 fingerprint image at a time. Also, it considers problems for focus and rolling in touchless fingerprint recognition for using camera. They affects fingerprint recognition, so this research is performed to measure and analyze these problems.