Iris Identification Technology Based on Multiwavelets

1IntroductionIris identification is reputed to be one of the mostreliable biometric identification technologies.Wavelettheory has been widely used in feature analysis of the irisimage-the key to this technology.The classical irisrecognition algorithms were developed by Daugman[1]and Wildes[2].Zero-crossings of the wavelet transformwas presented by Boles[3].Gabor filter optimizationdesign for iris texture analysis and a multi-matchingsystem based on a simplified deformable model of thehuman i…     

Modeling passive mechanical interaction between aqueous humor and iris.

Certain forms of glaucoma are associated with displacement of the iris from its normal contour. We present here a mathematical model of the coupled aqueous humor-iris system that accountsfor the contribution of aqueous humor flow and passive iris deformability to the iris contour. The aqueous humor is modeled as a Newtonian fluid, and the iris is modeled as a linear elastic solid. The resulting coupled equation set is solved by the finite element method with mesh motion in response to iris displacement accomplished by tracking a pseudo-solid overlying the aqueous humor. The model is used to predict the iris contour in healthy and diseased eyes. The results compare favorably with clinical observations, supporting the hypothesis that passive iris deformation can produce the iris contours observed using ultrasound biomicroscopy.     

Video Sequence-Based Iris Recognition Inspired by Human Cognition Manner

In video sequence-based iris recognition system, the problem of making full use of relationship and correlation among frames still remains to be solved. A brand new template level multimodal fusion algorithm inspired by human cognition manner is proposed. In that a non-isolated geometrical manifold, named Hyper Sausage Chain due to its sausage shape, is trained using the frames from a pattern class for representing an iris class in feature space. We can classify any input iris by observing which manifold it locates in. This process is closer to the function of human being, which takes ＇matter cognition＇ instead of ＇matter classification＇ as its basic principle. The experiments on self-developed JLUBR-IRIS dataset with several video sequences per person demonstrate the effectiveness and usability of the proposed algorithm for video sequence-based iris recognition. Fur- thermore, the comparative experiments on public CASIA-I and CASIA-V4-Interval datasets show that our method can also achieve improved performance of image-based iris recognition system, provided enough samples are involved in training stage.     

Compounding Local Invariant Features and Global Deformable Geometry for Medical Image Registration

Using deformable models to register medical images can result in problems of initialization of deformable models and robustness and accuracy of matching of inter-subject anatomical variability. To tackle these problems, a novel model is proposed in this paper by compounding local invariant features and global deformable geometry. This model has four steps. First, a set of highly-repeatable and highly-robust local invariant features, called Key Features Model (KFM), are extracted by an effective matching strategy. Second, local features can be matched more accurately through the KFM for the purpose of initializing a global deformable model. Third, the positional relationship between the KFM and the global deformable model can be used to precisely pinpoint all landmarks after initialization. And fourth, the final pose of the global deformable model is determined by an iterative process with a lower time cost. Through the practical experiments, the paper finds three important conclusions. First, it proves that the KFM can detect the matching feature points well. Second, the precision of landmark locations adjusted by the modeled relationship between KFM and global deformable model is greatly improved. Third, regarding the fitting accuracy and efficiency, by observation from the practical experiments, it is found that the proposed method can improve % of the fitting accuracy and reduce around 50% of the computational time compared with state-of-the-art methods.     

Using an Improved SIFT Algorithm and Fuzzy Closed-Loop Control Strategy for Object Recognition in Cluttered Scenes

Partial occlusions, large pose variations, and extreme ambient illumination conditions generally cause the performance degradation of object recognition systems. Therefore, this paper presents a novel approach for fast and robust object recognition in cluttered scenes based on an improved scale invariant feature transform (SIFT) algorithm and a fuzzy closed-loop control method. First, a fast SIFT algorithm is proposed by classifying SIFT features into several clusters based on several attributes computed from the sub-orientation histogram (SOH), in the feature matching phase only features that share nearly the same corresponding attributes are compared. Second, a feature matching step is performed following a prioritized order based on the scale factor, which is calculated between the object image and the target object image, guaranteeing robust feature matching. Finally, a fuzzy closed-loop control strategy is applied to increase the accuracy of the object recognition and is essential for autonomous object manipulation process. Compared to the original SIFT algorithm for object recognition, the result of the proposed method shows that the number of SIFT features extracted from an object has a significant increase, and the computing speed of the object recognition processes increases by more than 40%. The experimental results confirmed that the proposed method performs effectively and accurately in cluttered scenes.     

Mechanical characterization of the bovine iris

Quantification of the mechanical properties of the iris is necessary to assess the clinical significance of passive iris deformation, which has been suggested as a mechanism for certain forms of glaucoma. Extension tests were performed on isolated bovine irises to determine the passive mechanical behavior of the iris and the contribution of each of its two constituent muscles, the sphincter iridis and the dilator pupillae, to the overall properties. Because of the shape of the iris and our desire to use intact tissue, a “loop” experiment was performed in which the iris was stretched by hooking the sample and pulling. A simple mathematical model was used to account for the geometry of the experiment and the progressive recruitment of tissue. Radial extension experiments on samples dissected from the iris were also performed. The iris was found to be anisotropic, elastic, and incompressible. The average azimuthal Young's modulus of the sphincter was found to be 340 kPa; the average azimuthal Young's modulus of the dilator was found to be 890 kPa, which was significantly higher (p<0.01). The radial Young's modulus of the dilator was found to be 9.6 kPa, much lower than the azimuthal value.     

Multilocus OCA2 genotypes specify human iris colors

Human iris color is a quantitative, multifactorial phenotype that exhibits quasi-Mendelian inheritance. Recent studies have shown that OCA2 polymorphism underlies most of the natural variability in human iris pigmentation but to date, only a few associated polymorphisms in this gene have been described. Herein, we describe an iris color score (C) for quantifying iris melanin content in-silico and undertake a more detailed survey of the OCA2 locus (n = 271 SNPs). In 1,317 subjects, we confirmed six previously described associations and identified another 27 strongly associated with C that were not explained by continental population stratification (OR 1.5–17.9, P = 0.03 to <0.001). Haplotype analysis with respect to these 33 SNPs revealed six haplotype blocks and 11 hap-tags within these blocks. To identify genetic features for best-predicting iris color, we selected sets of SNPs by parsing P values among possible combinations and identified four discontinuous and non-overlapping sets across the LD blocks (p-Selected SNP sets). In a second, partially overlapping sample of 1,072, samples with matching diplotypes comprised of these p-Selected OCA2 SNPs exhibited a rate of C concordance of 96.3% (n = 82), which was significantly greater than that obtained from randomly selected samples (62.6%, n = 246, P<0.0001). In contrast, the rate of C concordance using diplotypes comprised of the 11 identified hap-tags was only 83.7%, and that obtained using diplotypes comprised of all 33 SNPs organized as contiguous sets along the locus (defined by the LD block structure) was only 93.3%. These results confirm that OCA2 is the major human iris color gene and suggest that using an empirical database-driven system, genotypes from a modest number of SNPs within this gene can be used to accurately predict iris melanin content from DNA. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Technical note: quantitative measures of iris color using high resolution photographs

Our understanding of the genetic architecture of iris color is still limited. This is partly related to difficulties associated with obtaining quantitative measurements of eye color. Here we introduce a new automated method for measuring iris color using high resolution photographs. This method extracts color measurements in the CIE 1976 L*a*b* (CIELAB) color space from a 256 by 256 pixel square sampled from the 9:00 meridian of the iris. Color is defined across three dimensions: L* (the lightness coordinate), a* (the red-green coordinate), and b* (the blue-yellow coordinate). We applied this method to a sample of individuals of diverse ancestry (East Asian, European and South Asian) that was genotyped for the HERC2 rs12913832 polymorphism, which is strongly associated with blue eye color. We identified substantial variation in the CIELAB color space, not only in the European sample, but also in the East Asian and South Asian samples. As expected, rs12913832 was significantly associated with quantitative iris color measurements in subjects of European ancestry. However, this SNP was also strongly associated with iris color in the South Asian sample, although there were no participants with blue irides in this sample. The usefulness of this method is not restricted only to the study of iris pigmentation. High-resolution pictures of the iris will also make it possible to study the genetic variation involved in iris textural patterns, which show substantial heritability in human populations.     

The color and structure of the human iris. 1. Morphological studies]

The material basis of this investigation consists of empirical findings and colour photographs of the irises of 200 pairs of twins and 100 control pairs. For the morphological investigation first-born twins and control persons are combined to constitute a comparative group of 400 non-related testees. Research by means of the iris microscope and the evaluation of standardized iris photographs led to the development of a catalogue of features which describes 10 iris characteristics for the iris colour and 20 for the iris structure. For each feature different degrees of markedness are defined and their frequency is determined. Similarly, intraindividual right/left and sex differences as well as age-dependencies and the relation between the features are examined. The setting-up of features includes outlining an iris-colour class system in order to render a better and more practicable determination of eye colour possible. As a substitute for Martin/Schulz's table of eye-colour, which describes only eye-colour phenomena, 4 iris-colour classes are set up whose main criterion of classification is the quantity of pigment. When we consider the testees of all age classes, sex differences have no statistical relevance as for iris colour. Only in the case of male testees may an intensive decrease of blue and brown iris colour in favour of combination colours (yellow pigment colours in particular) be observed during the phase of puberty. Therefore, the brightening postulated in the relevant literature can be confirmed. With regard to female testees, in contrast, pigment shifting is of no statistical relevance. After a slight brightening the irises numerically re-darken at the adult-stage to the initial child level, i.e. they become "dark again" rather than just become "darker". Within the iris structure only the characteristics of the anterior stroma leaf show sex differences. They are, however, only weakly marked and can be described merely as a trend. Over the whole range of the age classes, there are no outstanding structural differences. The different iris characteristics concerning iris colour stand in a significant relation to each other. When we consider the statistically relevant relations between structural features, it becomes clear that particularly reduced and particularly intact iris characteristics correlate. Thus, we can distinguish between an intact type of iris and a reduced one. Three quarters of the testees, however, combine reduced and intact properties with medium degrees of markedness.(ABSTRACT TRUNCATED AT 400 WORDS)     

In vivo non-contact measurement of human iris elasticity by optical coherence elastography

Quantifying the mechanical properties of the iris can offer valuable insights into the pathophysiology of primary angle closure glaucoma. However, current techniques for iris elastography remain ex vivo with limited clinical applications. This article describes a proposition for a non-contact and non-invasive air-puff optical coherence elastography (OCE) system that can evaluate iris elasticity in vivo. Ten eyes recruited from seven subjects underwent OCE imaging acquisition under three different illumination conditions. The Young's modulus of each eye was detected and shown to be inversely proportional to the iris length, indicating a relationship between mechanical properties and morphology of the iris. With its noninvasive and high-resolution features, this air-puff system shows great potential for applications in clinical ophthalmology.     

Sequences associated with human iris pigmentation

To determine whether and how common polymorphisms are associated with natural distributions of iris colors, we surveyed 851 individuals of mainly European descent at 335 SNP loci in 13 pigmentation genes and 419 other SNPs distributed throughout the genome and known or thought to be informative for certain elements of population structure. We identified numerous SNPs, haplotypes, and diplotypes (diploid pairs of haplotypes) within the OCA2, MYO5A, TYRP1, AIM, DCT, and TYR genes and the CYP1A2-15q22-ter, CYP1B1-2p21, CYP2C8-10q23, CYP2C9-10q24, and MAOA-Xp11.4 regions as significantly associated with iris colors. Half of the associated SNPs were located on chromosome 15, which corresponds with results that others have previously obtained from linkage analysis. We identified 5 additional genes (ASIP, MC1R, POMC, and SILV) and one additional region (GSTT2-22q11.23) with haplotype and/or diplotypes, but not individual SNP alleles associated with iris colors. For most of the genes, multilocus gene-wise genotype sequences were more strongly associated with iris colors than were haplotypes or SNP alleles. Diplotypes for these genes explain 15% of iris color variation. Apart from representing the first comprehensive candidate gene study for variable iris pigmentation and constituting a first step toward developing a classification model for the inference of iris color from DNA, our results suggest that cryptic population structure might serve as a leverage tool for complex trait gene mapping if genomes are screened with the appropriate ancestry informative markers.     

Ocular prosthesis for a geriatric patient with customised iris: a report of two cases

doi:10.1111/j.1741‐2358.2009.00327.x
Ocular prosthesis for a geriatric patient with customised iris: a report of two cases Objective: An ocular prosthesis is given when trauma or disease may lead to enucleation or evisceration of the eye and the combined efforts of the ophthalmologists and the maxillofacial prosthetist can provide a cosmetically acceptable ocular prosthesis. Methods: An ocular prosthesis is either pre‐fabricated or custom‐made. One of the important factors for achieving a cosmetic result is accurate colour matching of the iris with the contralateral iris. Results: A knowledge of the anatomy of the eye facilitates hand painting of iris and sclera to produce a satisfactory result. Conclusion: The custom‐made ocular prosthesis allows infinite variations during the fabrication.     

An alternative method for irones quantification in iris rhizomes using headspace solid-phase microextraction

Introduction – The essential oil obtained from iris rhizomes is one of the most precious raw materials for the perfume industry. Its fragrance is due to irones that are gradually formed by oxidative degradation of iridals during rhizome ageing. Objective – The development of an alternative method allowing irone quantification in iris rhizomes using HS‐SPME‐GC. Methodology – The development of the method using HS‐SPME‐GC was achieved using the results obtained from a conventional method, i.e. a solid–liquid extraction (SLE) followed by irone quantification by CG. Results – Among several calibration methods tested, internal calibration gave the best results and was the least sensitive to the matrix effect. The proposed method using HS‐SPME‐GC is as accurate and reproducible as the conventional one using SLE. These two methods were used to monitor and compare irone concentrations in iris rhizomes that had been stored for 6 months to 9 years. Conclusion – Irone quantification in iris rhizome can be achieved using HS‐SPME‐GC. This method can thus be used for the quality control of the iris rhizomes. It offers the advantage of combining extraction and analysis with an automated device and thus allows a large number of rhizome batches to be analysed and compared in a limited amount of time. Copyright © 2010 John Wiley & Sons, Ltd.     

Contact-Free Palm-Vein Recognition Based on Local Invariant Features

Contact-free palm-vein recognition is one of the most challenging and promising areas in hand biometrics. In view of the existing problems in contact-free palm-vein imaging, including projection transformation, uneven illumination and difficulty in extracting exact ROIs, this paper presents a novel recognition approach for contact-free palm-vein recognition that performs feature extraction and matching on all vein textures distributed over the palm surface, including finger veins and palm veins, to minimize the loss of feature information. First, a hierarchical enhancement algorithm, which combines a DOG filter and histogram equalization, is adopted to alleviate uneven illumination and to highlight vein textures. Second, RootSIFT, a more stable local invariant feature extraction method in comparison to SIFT, is adopted to overcome the projection transformation in contact-free mode. Subsequently, a novel hierarchical mismatching removal algorithm based on neighborhood searching and LBP histograms is adopted to improve the accuracy of feature matching. Finally, we rigorously evaluated the proposed approach using two different databases and obtained 0.996% and 3.112% Equal Error Rates (EERs), respectively, which demonstrate the effectiveness of the proposed approach.     

Improved detection of iris severe mosaic virus in secondarily-infected iris bulbs

The influence of wounding and high-temperature treatment on the detection of iris severe mosaic virus (ISMV) in secondarily ISMV-infected iris bulbs was studied. Wounding of the bulbs just after lifting, followed by storage for 3 wk at 17°C or 20°C, increased the detectability of ISMV to 100% reliability. High-temperature treatment and consecutive storage at 17°C induced a similar improvement of detection. It is concluded that a certain degree of stress, such as wounding or high-temperature treatment, ultimately leads to an increase in viral antigens and thus to improvement of detection. It is hypothesised that the virus titre increases by the altered metabolism during the repair reactions as a response to stress applied to the bulbs.     

Ultrastructure of the striated muscle tissue of the iris of birds]

Heteromorphism of the contractile elements of the iris muscular tissue in chick embryos and in chickens has been studied by means of electron microscopical investigation. The leading contractile tissue of the iris is the striated muscular tissue, which is formed as a cellular-simplastic system with its own cambium-myosatellitocytes. Some cells, containing myofilaments in their cytoplasm, are related to myofibroblastic and smooth muscle differons, which functions remain to be studied. A hypothesis is proposed on existence of two sources for development of the iris muscular elements. The first-stem cells for the striated muscular tissue; at early stages of embryonal development they are included into composition of ectomesenchyme of the neural crest and migrate into the area of the muscle anlages. The second-cells migrating from the ocular cup margins and developing into the smooth myocytes of the iris.     

基于图像特征的实蝇自动识别初步研究

针对实蝇图象识别,提出了基于局部模板匹配和分层约束的虫身局部特征检测的算法,该算法将虫身局部特征搜索分为三个层次:首先是图像中的实蝇虫身检测,找到实蝇图像上虫身的大概位置;其次是用虫身明显特征模板作虫身检测;最后根据不同实蝇的典型特征区别出这些实蝇所属的不同类别.在图像预处理时采用主成分分析(PCA)方法进行主轴定位并旋转归一化处理.在对虫身翅膀上的明显特征进行检测时,提出了翅膀斑纹模板匹配算法.