Kevin W. Bowyer - Iris Biometrics

Our 2008 survey paper on iris biometrics provides an excellent introduction to the state of iris biometrics research up to that time. Iris biometric research efforts in our Computer Vision Research Lab span four major themes. A underlying foundation is the emphasis on large-scale experimental validation.

One major theme in our iris biometrics research is the development of algorithms to improve the accuracy of iris biometrics. Our work on dilation-aware enrollment, fragile bit masking, averaging of frames of iris video and spatial coincidence of fragile bit locations are examples of research that introduces new approaches to improving the accuracy of iris biometrics.

Another theme of our research is the exploration of basic phenomena involved in imaging the texture of the iris. Our work on the effects of pupil dilation, contact lenses and template aging are examples of research results within this theme. Our work on each of these topics disproves some element of previous conventional wisdom about iris biometrics. Our conclusions about the effects of pupil dilation on the accuracy of iris biometrics have since been reproduced in the NIST IREX study; see NIST Interagency Report 7629.

A third and still developing theme might be called "iris forensics". This theme deals with analyzing iris texture to obtain information other than identity. Our work on determining gender from iris texture is an example of this. Additional examples include our work on the similarity of iris texture between the left and right iris of a person and similarity of iris texture between identical twins (see here) and categories of similar iris texture across a general population. Our initial work on texture similarity between left and right irises, and between irises of identical twins, uses experiments with human observers to demonstrate that texture similarity does exist, even though current iris biometrics texture analysis methods are not able to detect the similarity.

A fourth theme in our work is support of government programs in biometrics. Our research group has been a part of the support team for the Iris Challenge Evaluation and Multiple Biometric Grand Challenge, among other programs. The FRVT / ICE results paper appearing in PAMI, and the MBGC overview paper are examples. We have also made a large (60,000+) set of iris images available to the research community, the ND_IRIS_04_05 dataset.

Video of Professor Bowyer's seminar on Next-Generation Iris Biometrics given in the Distinguished Lecture Series at UIUC's Information Trust Institute on December 1, 2008: about 800 MB, about 63 minutes, mov format. slides from the talk.

Undergrad researcher Sarah Ring is featured in a two-minute video that ran during halftime of the nationally-televised 2007 Notre Dame - Duke football game. Sarah presented a conference paper at BTAS 2008 on her work on the effect of contact lenses on iris biometrics.

  • The Results of the NICE.II Iris Biometrics Competition,
    Kevin W. Bowyer,
    Pattern Recognition Letters, to appear.
    pdf of this paper.
    ... NICE.II focused on performacne in feature extraction and matching. The eight top-performing algortihsm from NICE.II are considered, and suggestions are made for lessons that can be drawn from the results.

  • Human and Machine Performance on Periocular Biometrics Under Near-Infrared Light and Visible Light.
    Karen P. Hollingsworth, Shelby S. Darnell, Philip E. Miller, Damon L. Woodard, Kevin W. Bowyer and Patrick J. Flynn,
    IEEE Transactions on Information Forensics and Security, to appear.
    pdf of this paper.
    ... Previous periocular research has used either visible light or near-infrared light images, but no prior research has directly compared the two illuminations using images with similar resolution. We conducted an experiment in which volunteers were asked to compare pairs of periocular images. ... We calculated performance of three computer algorithms on the periocular images. Performance for humans and computers was similar.

  • Useful Features for Human Verification in Near-Infrared Periocular Images,
    Karen Hollingsworth, Kevin W. Bowyer and Patrick J. Flynn,
    Image and Vision Computing Journal, to appear.
    pdf of this paper.
    ... We conducted two experiments to determine how humans analyze periocular images. In these experiments, we presented pairs of images and asked volunteers to determine whether the two images showed eyes from the same subject or from different subjects. ...

  • Predicting Ethnicity and Gender from Iris Texture,
    Stephen Lagree and Kevin W. Bowyer,
    IEEE International Conference on Technologies for Homeland Security, November 2011, Boston, MA.
    pdf of this paper.
    Previous researchers have reported success in predicting ethnicity and predicting gender from features of the iris texture. This paper is the first to consider both problems from similar experimental approaches. Contributions of this work include greater accuracy than previous work on predicting ethnicity from iris texture, empirical evidence that suggests that gender prediction is harder than ethnicity prediction, and empirical evidence that ethnicity prediction is more difficult for females than for males.

  • Useful Features for Human Verification in Near-Infrared Periocular Images,
    Karen Hollingsworth, Kevin W. Bowyer and Patrick J. Flynn,
    Image and Vision Computing Journal, to appear.

  • Dilation Aware Multi-Image Enrollment for Iris Biometrics
    Estefan Ortiz and Kevin W. Bowyer
    International Joint Conference on Biometrics (IJCB 2011), October 2011.
    pdf of this paper.
    ... the probability of a false non-match increases when there is a considerable variation in pupil size between the enrolled eye image and the probe eye image. ... Our research examines a strategy to improve system performance by implementing a dilation-aware enrollment phase that chooses eye images based on their respective empirical dilation ratio distribution. ... Our results show that there is a noticeable improvement over the random scenario when pupil dilation is accounted for during the enrollment phase.

  • What Surprises Do Identical Twins Have for Identity Science?
    Kevin W. Bowyer,
    IEEE Computer 44(7), July 2011, 100-102.
    pdf of this paper.
    Experiments with biometric datasets from identical twins are helping to shape future research in face and iris recognition.

  • Genetically Identical Irises Have Texture Similarity That Is Not Detected By Iris Biometrics,
    Karen Hollingsworth, Kevin W. Bowyer and Patrick J. Flynn,
    Computer Vision and Image Understanding 115, 1493-1502, 2011.
    pdf of this paper.
    As the standard iris biometric algorithm "sees" them, the left and right irises of the same person are as different as irises of unrelated people. Similarly, in terms of iris biometric matching, the eyes of identical twins are as different as irises of unrelated people. The left and right eyes of an individual or the eyes of identical twins are examples of genetically identical irises. In experiments with human observers viewing pairs of iris images acquired using an iris biometric system, we have found that there is recognizable similarity in the left and right irises of an individual and the irises of identical twins. This result suggests that iris texture analysis different from that performance in the standard iris biometric algorithm may be able to answer questions that iris biometrics cannot answer.

  • Improved Iris Recognition Through Fusion of Hamming Distance and Fragile Bit Distance,
    Karen Hollingsworth, Kevin W. Bowyer and Patrick J. Flynn.
    IEEE Transactions on Pattern Analysis and Machine Intelligence, to appear.
    pdf of this paper.
    ... We find that the locations of fragile bits tend to be consistent across different iris codes of the same eye. We present a metric, called the fragile bit distance, which quantitatively measures the coincidence of the fragle bit patterns in two iris codes. We find that score fusion of fragile bit distances and Hamming distance works better for recognition than Hamming distance alone. To our knowledge, this is the first and only work to use the coincidence of fragile bit locations to improve the accuracy of matches.

  • A Cross-Sensor Evaluation of Three Commercial Iris Cameras for Iris Biometrics,
    Ryan Connaughton, Amanda Sgroi, Kevin W. Bowyer and Patrick J. Flynn,
    IEEE Computer Society Workshop on Biometrics, June 2011.
    pdf of this paper.
    ... This work presents experiments which compare three commercially available iris sensors and investigates the impact of cross-sensor matching on system performance. ...

  • Experimental evidence of a template aging effect in iris biometrics,
    Sam Fenker and Kevin W. Bowyer,
    IEEE Computer Society Workshop on Applications of Computer Vision, January 2011.
    pdf of this paper.
    Baker et al recently presented the first published evidence of a template aging effect, using images acquired from 2004 through 2008 with an LG 2200 iris imaging system, representing a total of 13 subjects (26 irises). We report on a template aging study involving two different iris recognition algorithms, a larger number of subjects (43), a more modern imaging system (LG 4000), and over a shorter time-lapse (2 years). We also investigate the degree to which the template aging effect may be related to pupil dilation and/or contact lenses.

  • Identifying useful features for recognition in near-infrared periocular images
    Karen Hollingsworth, Kevin W. Bowyer and Patrick J Flynn,
    Biometrics Theory, Applications and Systems (BTAS).
    pdf of this paper.
    ... We presented pairs of periocular images to testers and asked them to determine whether the two images were from the same person or from different people. Our testers correctly determined the relationship in over 90% of the queries. We asked them to describe what features in the images were helpful to them in making their decisions. We found that eyelashes, tear ducts, shape of the eye, and eyelids were used most frequently in determining whether two images were of the same person. ...

  • Human perceptual categorization of iris texture patterns,
    Louise Stark, Kevin W. Bowyer and Stephen Siena,
    Biometrics Theory, Applications and Systems (BTAS).
    pdf of this paper.
    We report on an experiment in which observers were asked to browse a set of 100 iris images and group them into categories based on similarity of overall texture appearance. Results indicate that there is a natural categorization of iris images into a small number of high-level categories, and then also into sub-categories. ...

  • Degradation of iris recognition performance due to non-cosmetic prescription contact lenses,
    Sarah Baker, Amanda Hentz, Kevin W. Bowyer and Patrick J. Flynn,
    Computer Vision and Image Understanding 114 (9), 1030-1044, September 2010.
    pdf of this paper.
    Many iris recognition systems operate under the assumption that non-cosmetic contact lenses have no or minimal effect on iris biometrics performance. ... This is the first study to document degraded iris biometrics performance with non-cosmetic contact lenses.

  • Human Versus Biometric Perception of Iris Texture,
    Presentation only of work done with Karen Hollingsworth, Steve Lagree, Sam Fenker and Patrick J. Flynn,
    Biometrics Consortium Conference (BCC), September 2010, Tampa, FL.
    pdf of slides.

  • Introduction to the Special Issue on Recent Advances In Biometrics,
    Kevin W. Bowyer,
    IEEE Transactions on Systems, Man and Cybernetics - Part A, 40 (3), May 2010, 434-436.
    pdf of this paper.
    As with BTAS 07, a biometrics-themed special issue of Systems Man and Cybernetics - Part A was organized following BTAS 08. However, unlike the SMC-A special section drawn from BTAS 07, this special issue had an "open" call for papers, meaning that submissions were not limited to papers presented at BTAS 08. ... A total of 31 submissions were received for the special issue. ... The ten papers that appear in this special issue represent the result of this process. Four of the ten papers appearing in this special issue are revised and extended versions of papers presented in the closing session of the BTAS 08 conference, a session which, by BTAS tradition, is reserved for the submissions that receive the overall best reviews from the conference program committee. The papers in this special issue cover a range of different biometric modalities, including face, ear, iris, signature and multi-modal. In the area of face recognition, there are papers dealing with 2D, 3D, and hand-drawn sketches. Also, the papers in this special issue range from relatively application oriented to relatively theoretical. One common theme is that each paper addresses an important current topic in biometrics research and makes a novel contribution to the state of the art.

  • Factors That Degrade the Match Distribution In Iris Biometrics,
    Kevin W. Bowyer, Sarah E. Baker, Amanda Hentz, Karen Hollingsworth, Tanya Peters and Patrick J. Flynn,
    Identity in the Information Society, 2 (3) 327-343, December 2009.
    DOI link. (open access)
    We consider three "accepted truths" about iris biometrics, involving pupil dilation, contact lenses and template aging. We also consider a relatively ignored issue that may arise in system interoperability. Experimental results from our laboratory demonstrate that the three accepted truths are not entirely true, and also that interoperability can involve subtle performance degradation. All four of these problems affect primarily the stability of the match, or authentic, distribution of template comparison scores rather than the non-match, or imposter, distribution of scores. In this sense, these results confirm the security of iris biometrics in an identity verification scenario. We consider how these problems affect the usability and security of iris biometrics in large-scale applications, and suggest possible remedies.

  • Iris Recognition Using Signal-level Fusion of Frames from Video,
    Karen P. Hollingsworth, Tanya Peters, Kevin W. Bowyer and Patrick J. Flynn,
    IEEE Transactions on Information Forensics and Security 4 (4), 837-848, December 2009.
    pdf of this paper.
    DOI link.
    We take advantage of the temporal continuity in an iris video to improve matching performance using signal-level fusion. From multiple frames of a frontal iris video, we create a single average image. ... No published prior work has shown any advantage of the use of video over still images in iris biometrics.

  • Using Fragile Bit Coincidence to Improve Iris Recognition,
    Karen P. Hollingsworth, Kevin W. Bowyer and Patrick J. Flynn,
    Biometrics: Theory, Applications and Systems (BTAS 09), September 2009, Washington, DC.
    pdf of this paper.
    ... Previous research has shown that iris recognition performance can be improved by making these fragile bits. ... We find that the locations of fragile bits tend to be consistent across different iris codes of the same eye. We present a metrics, called the fragile bit distance, which quantitatively measures the coincidence of the fragile bit patterns in two iris codes. We find that score-fusion of fragile bit distance and Hamming distance works better for recognition than Hamming distance alone. This is the first and only work that we are aware of to use the coincidence of fragile bit locations to improve the accuracy of matches.

  • Stability of the Iris Match Distribution,
    Presentation only of work done with Karen Hollingsworth, Sarah Baker, Amanda Hentz, Tanya Peters and Patrick J. Flynn,
    Biometrics Consortium Conference (BCC), September 2009, Tampa, FL.
    pdf of slides.

  • The ND-IRIS-0405 Iris Image Dataset,
    Kevin W. Bowyer and Patrick J. Flynn,
    Notre Dame CVRL Technical Report.
    pdf of this report.
    The Computer Vision Research Lab at the University of Notre Dame began collecting iris images in the spring semester of 2004. The initial data collections used an LG 2200 iris imaging system for image acquisition. Image datasets acquired in 2004-2005 at Notre Dame with this LG 2200 have been used in the ICE 2005 and ICE 2006 iris biometric evaluations. The ICE 2005 iris image dataset has been distributed to over 100 research groups around the world. The purpose of this document is to describe the content of the ND-IRIS-0405 iris image dataset. This dataset is a superset of the iris image datasets used in ICE 2005 and ICE 2006.

  • FRVT 2006 and ICE 2006 Large-Scale Experimental Results,
    P. Jonathon Phillips, W. Todd Scruggs, Alice O'Toole, Patrick J. Flynn, Kevin W. Bowyer, Cathy L. Schott and Matthew Sharpe,
    IEEE Transactions on Pattern Analysis and Machine Intelligence 32 (5), May 2010, 831-846.
    pdf of this paper.
    DOI link.
    This paper describes the large-scale experimental results from the Face Recognition Vendor Test (FRVT) 2006 and the Iris Challenge Evaluation (ICE) 2006. ...

  • Empirical Evidence for Correct Iris Match Score Degradation With Increased Time Lapse Between Gallery and Probe Images,
    Sarah Baker, Kevin W. Bowyer and Patrick J. Flynn,
    International Conference on Biometrics, June 2009, 1170-1179.
    pdf of this paper.
    We explore the effects of time lapse on iris biometrics using a data set of images with four years time lapse between the earliest and the most recent images of an iris (13 subjects, 26 irises, 1809 total images. We find that the average fractional distance for a match between two images of an iris taken four years apart is significantly larger than the match for images with only a few months time lapse between them. ... To our knowledge, this is the first and only experimental study of iris match scores under long (multi-year) time lapse.

  • Overview of the Multiple Biometric Grand Challenge,
    P. Jonathon Phillips, Todd Scruggs, Patrick Flynn, Kevin W. Bowyer, Ross Beveridge, Geoff Givens, Bruce Draper and Alice O'Toole,
    International Conference on Biometrics, June 2009, 705-714.
    pdf of this paper.
    The goal of the Multiple Biometric Grand Challenge (MBGC) is to improve the performance of face and iris recognition technology from samples acquired under unconstrained conditions. The MBGC is organized into three challenge problems. Each challenge problem relaxes the constraints in different directions. ...

  • Image Averaging for Improved Iris Recognition,
    Karen Hollingsworth, Kevin W. Bowyer and Patrick J. Flynn,
    International Conference on Biometrics, June 2009, 1112-1121.
    pdf of this paper.
    We take advantage of the temporal continuity in an iris video to improve matching performance using signal-level fusion. From multiple frames of an iris video, we create a single average image. Our signal-level fusion method performs better that methods based on single still images, and better than previously published multi-gallery score-fusion methods. ...

  • Towards the Next Generation of Iris Biometrics Science,
    Kevin W. Bowyer, Patrick J. Flynn, Karen Hollingsworth, Sarah Baker and Sarah Ring.
    SPIE Newsroom, 2009. DOI link: http://dx.doi.org/10.1117/2.1200904.1595.
    pdf of this paper.
    (A SPIE Newsroom article that gives an overview of the paper and invited talk.)

  • Recent Research Results In Iris Biometrics,
    Karen Hollingsworth, Sarah Baker, Sarah Ring, Kevin W. Bowyer and Patrick J. Flynn,
    SPIE 7306B: Biometric Technology for Human Identification VI, April 2009.
    pdf of this paper.
    ... we have collected more than 100,000 iris images for use in iris biometrics research. Using this data, we have developed a number of techniques for improving recognition rates. These techniques include fragile bit masking, signal-level fusion of iris images, and detecting local distortions in iris texture. Additionally, we have shown that large degrees of dilation and long lapses of time between image acquisitions negatively impact performance.

  • Introduction to the Special Section of Best Papers from the 2007 Biometrics: Theory, Applications and Systems Conference,
    Kevin W. Bowyer,
    IEEE Transactions on Systems, Man and Cybernetics - Part A, 39 (1), January 2009, 2-3.
    pdf of this paper.
    DOI link.
    ... Over 100 papers were submitted to BTAS 07. ... The final result of this process is the set of five papers that appear in this special section. We are particularly fortunate in the way that the five papers in this special section illustrate the breadth of activities in current biometrics research. Face, fingerprint, iris, voice, handwriting, and multimodal biometrics are all represented. ...

  • Pupil Dilation Degrades Iris Biometric Performance,
    Karen Hollingsworth, Kevin W. Bowyer and Patrick J. Flynn,
    Computer Vision and Image Understanding, 113 (1), January 2009, 150-157.
    pdf of this paper.
    DOI link.
    ... We found that when the degree of dilation is similar at enrollment and recognition, comparisons involving highly dilated pupils result in worse recognition performance than comparisons involving constricted pupils. We also found that when the matched images have similarly highly dilated pupils, the mean Hamming distance of the match distribution increases and the mean Hamming distance of the non-match distribution decreases, bringing the distributions closer together from both directions. We further found that when matching enrollment and recognition images of the same person, larger differences in pupil dilation yield higher template dissimilarities, and so a greater chance of a false non-match. ...
    Our research group is part of the Multiple Biometric Grand Challenge and Iris Challenge Evaluation support teams.

  • The Best Bits in an Iris Code,
    Karen Hollingsworth, Kevin W. Bowyer and Patrick J. Flynn,
    IEEE Transactions on Pattern Analysis and Machine Intelligence 31 (6), 964-973, June 2009.
    pdf of this paper.
    ... The fractional Hamming distance weights all bits in an iris code equally. However, not all the bits in an iris code are equally useful. Our research is the first to present experiments documenting that some bits are more consistent than others. ... The inconsistencies are largely due to the coarse quantization of the phase response. Masking iris code bits corresponding to complex filter responses near the axes of the complex plane improves the separation between the match and nonmatch Hamming distance distributions.
    Our research group is part of the Multiple Biometric Grand Challenge and Iris Challenge Evaluation support teams.

  • Detection of Iris Texture Distortions By Analyzing Iris Code Matching Results,
    Sarah Ring and Kevin W. Bowyer,
    Biometrics: Theory, Applications and Systems (BTAS 08), September 2008, Washington, DC.
    pdf of this paper.
    Previous work in iris biometrics attempts to cope with occlusion by eyelids / eyelashes and with specular highlights through improved segmentation of the iris region. Our approach assumes that some local distortions of the iris texture are not detected at the segmentation stage, and that these generate corresponding regions of local distortion in the iris code derived from the image. We introduce an approach to detect such regions of local distortion in the iris code through analysis of the iris code matching results. We know of no previous work that attempts to detect distortions of iris texture through analyzing the iris code matching results.

  • The Iris Challenge Evaluation 2005,
    P. Jonathon Phillips, Kevin W. Bowyer and Patrick J. Flynn, Xiaomei Liu and W. Todd Scruggs,
    Biometrics: Theory, Applications and Systems (BTAS 08), September 2008, Washington, DC.
    DOI link.

  • Image Understanding for Iris Biometrics: A Survey,
    Kevin W. Bowyer, Karen Hollingsworth and Patrick J. Flynn,
    Computer Vision and Image Understanding, 110(2), 281-307, May 2008.
    DOI link.
    ... Most research publications can be categorized as making their primary contribution to one of the four major modules in iris biometrics: image acquisition, iris segmentation, texture analysis and matching of texture representations. Other important research includes experimental evaluations, image databases, applications and systems, and medical conditions that may affect the iris. ...
    Our research group is part of the Multiple Biometric Grand Challenge and Iris Challenge Evaluation support teams.

  • Learning to Predict Gender from Irises,
    Vince Thomas, Nitesh V. Chawla, Kevin W. Bowyer and Patrick J. Flynn,
    IEEE International Conference on Biometrics: Theory, Applications, and Systems (BTAS 07), September 2007.
    pdf of this paper.
    This paper employs machine learning techniques to develop models that predict gender based on the iris texture features. ...

  • Guest Editorial: Introduction to the Special Issue on Recent Advances in Biometric Systems,
    Kevin W. Bowyer, Venu Govindaraju and Nalini Ratha,
    IEEE Transactions on Systems, Man and Cybernetics - B 37 (5), October 2007.
    pdf of this paper.
    We are pleased to present 14 papers in this special issue devoted to recent advances in biometric systems. ...

  • Comment on the CASIA version 1.0 Iris Dataset,
    P. Jonathon Phillips, Kevin W. Bowyer and Patrick J. Flynn,
    IEEE Transactions on Pattern Analysis and Machine Intelligence 29 (10), October 2007.
    pdf of this paper.
    We note that the images in the CASIA version 1.0 iris dataset have been edited so that the pupil area is replaced by a circular region of uniform intensity. We recommend that this dataset is no longer used in iris biometrics research ...

  • FRVT 2006 and ICE 2006 Large-Scale Results,
    P. J. Phillips, W. T. Scruggs, A. J. O'Toole, P. J. Flynn, K.W. Bowyer, C. L. Schott, and M. Sharpe.
    National Institute of Standards and Technology, NISTIR 7408, http://face.nist.gov, 2007.
    pdf of this report.
    This report describes the large-scale experimental results from the Face Recognition Vendor Test (FRVT) 2006 and the Iris Challenge Evaluation (ICE) 2006. ...
    Our research group is part of the Multiple Biometric Grand Challenge and Iris Challenge Evaluation support teams.

  • Experiments With an Improved Iris Segmentation Algorithm,
    Xiaomei Liu, Kevin W. Bowyer, and Patrick J. Flynn,
    Fourth IEEE Workshop on Automatic Identification Advanced Technologies (AutoID), October 2005, New York, 118-123.
    pdf of this paper.
    ... We have also developed and implemented an improved iris segmentation and eyelid detection stage of the algorithm, and experimentally verified the improvement in recognition performance using the collected dataset. Compared to Masek's original segmentation approach, our improved segmentation algorithm leads to an increase of over 6% in the rank-one recognition rate.

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