-
Sensors (Basel, Switzerland) Nov 2022With the increasing popularity of smart devices, users can control their mobile phones, TVs, cars, and smart furniture by using voice assistants, but voice assistants...
With the increasing popularity of smart devices, users can control their mobile phones, TVs, cars, and smart furniture by using voice assistants, but voice assistants are susceptible to intrusion by outsider speakers or playback attacks. In order to address this security issue, a millimeter-wave radar-based voice security authentication system is proposed in this paper. First, the speaker's fine-grained vocal cord vibration signal is extracted by eliminating static object clutter and motion effects; second, the weighted Mel Frequency Cepstrum Coefficients (MFCCs) are obtained as biometric features; and finally, text-independent security authentication is performed by the WMHS (Weighted MFCCs and Hog-based SVM) method. This system is highly adaptable and can authenticate designated speakers, resist intrusion by other unspecified speakers as well as playback attacks, and is secure for smart devices. Extensive experiments have verified that the system achieves a 93.4% speaker verification accuracy and a 5.8% miss detection rate for playback attacks.
Topics: Computer Security; Voice; Radar; Biometry; Cell Phone
PubMed: 36502011
DOI: 10.3390/s22239309 -
Sensors (Basel, Switzerland) Sep 2013Conventional fingerprint verification systems use only static information. In this paper, fingerprint videos, which contain dynamic information, are utilized for...
Conventional fingerprint verification systems use only static information. In this paper, fingerprint videos, which contain dynamic information, are utilized for verification. Fingerprint videos are acquired by the same capture device that acquires conventional fingerprint images, and the user experience of providing a fingerprint video is the same as that of providing a single impression. After preprocessing and aligning processes, "inside similarity" and "outside similarity" are defined and calculated to take advantage of both dynamic and static information contained in fingerprint videos. Match scores between two matching fingerprint videos are then calculated by combining the two kinds of similarity. Experimental results show that the proposed video-based method leads to a relative reduction of 60 percent in the equal error rate (EER) in comparison to the conventional single impression-based method. We also analyze the time complexity of our method when different combinations of strategies are used. Our method still outperforms the conventional method, even if both methods have the same time complexity. Finally, experimental results demonstrate that the proposed video-based method can lead to better accuracy than the multiple impressions fusion method, and the proposed method has a much lower false acceptance rate (FAR) when the false rejection rate (FRR) is quite low.
Topics: Algorithms; Artificial Intelligence; Biometry; Dermatoglyphics; Image Interpretation, Computer-Assisted; Pattern Recognition, Automated; Subtraction Technique; Video Recording
PubMed: 24008283
DOI: 10.3390/s130911660 -
BMC Ophthalmology May 2023To investigate the distribution and changes in ocular biometry in 4-to to 9-year-old Chinese children and to compare the differences between age and genders in these...
PURPOSE
To investigate the distribution and changes in ocular biometry in 4-to to 9-year-old Chinese children and to compare the differences between age and genders in these parameters.
METHODS
This was a school-based cross-sectional study. A total of 1,528 Chinese children, aged 4-9 years, from one primary school and 12 kindergartens, were included in the study. Axial length, corneal curvature, anterior chamber depth, and corneal diameter were measured for each child.
RESULTS
AL and anterior chamber depth gradually increased with age in both genders. No significant changes in corneal curvature or corneal diameter were detected at different ages in either genders group. The mean ALs of males and females were 22.94 ± 0.80 mm and 22.38 ± 0.79 mm, respectively. The mean corneal curvatures of males and females were 43.05 ± 1.37 D and 43.75 ± 1.48 D, respectively. The mean anterior chamber depth of males and females were 3.47 ± 0.24 mm and 3.38 ± 0.25 mm, respectively. The mean corneal diameter of males and females were 12.08 ± 0.43 mm and 11.94 ± 0.44 mm, respectively. Females had consistently shorter ALs, shorter anterior chamber depth, smaller corneal diameter, and steeper corneal curvatures than males at any age.
CONCLUSIONS
Boys had larger dimensions than girls for all ocular parameters except corneal curvature (flatter). Boys and girls showed similar trends for all parameters. Axial length and anterior chamber depth increased from 4 to 9 years of age, whereas corneal diameter and curvature did not change with age in either genders.
Topics: Child; Humans; Female; Male; Child, Preschool; Cross-Sectional Studies; East Asian People; Cornea; Asian People; Biometry; Refraction, Ocular; Anterior Chamber; Axial Length, Eye
PubMed: 37208745
DOI: 10.1186/s12886-023-02975-5 -
Biometrical Journal. Biometrische... May 2020In network meta-analysis (NMA), treatments can be complex interventions, for example, some treatments may be combinations of others or of common components. In standard...
In network meta-analysis (NMA), treatments can be complex interventions, for example, some treatments may be combinations of others or of common components. In standard NMA, all existing (single or combined) treatments are different nodes in the network. However, sometimes an alternative model is of interest that utilizes the information that some treatments are combinations of common components, called component network meta-analysis (CNMA) model. The additive CNMA model assumes that the effect of a treatment combined of two components A and B is the sum of the effects of A and B, which is easily extended to treatments composed of more than two components. This implies that in comparisons equal components cancel out. Interaction CNMA models also allow interactions between the components. Bayesian analyses have been suggested. We report an implementation of CNMA models in the frequentist R package netmeta. All parameters are estimated using weighted least squares regression. We illustrate the application of CNMA models using an NMA of treatments for depression in primary care. Moreover, we show that these models can even be applied to disconnected networks, if the composite treatments in the subnetworks contain common components.
Topics: Biometry; Depression; Humans; Models, Statistical; Primary Health Care
PubMed: 31021449
DOI: 10.1002/bimj.201800167 -
PloS One 2020Dendrochronology, the study of annual rings formed by trees and woody plants, has important applications in research of climate and environmental phenomena of the past....
Dendrochronology, the study of annual rings formed by trees and woody plants, has important applications in research of climate and environmental phenomena of the past. Since its inception in the late 19th century, dendrochronology has not had a way to quantify uncertainty about the years assigned to each ring (dating). There are, however, many woody species and sites where it is difficult or impossible to delimit annual ring boundaries and verify them with crossdating, especially in the lowland tropics. Rather than ignoring dating uncertainty or discarding such samples as useless, we present for the first time a probabilistic approach to assign expected ages with a confidence interval. It is proven that the cumulative age in a tree-ring time series advances by an amount equal to the probability that a putative growth boundary is truly annual. Confidence curves for the tree stem radius as a function of uncertain ages are determined. A sensitivity analysis shows the effect of uncertainty of the probability that a recognizable boundary is annual, as well as of the number of expected missing boundaries. Furthermore, we derive a probabilistic version of the mean sensitivity of a dendrochronological time series, which quantifies a tree's sensitivity to environmental variation over time, as well as probabilistic versions of the autocorrelation and process standard deviation. A computer code in Mathematica is provided, with sample input files, as supporting information. Further research is necessary to analyze frequency patterns of false and missing boundaries for different species and sites.
Topics: Biometry; Chronology as Topic; Climate; Models, Theoretical; Time Factors; Trees; Wood
PubMed: 32960924
DOI: 10.1371/journal.pone.0239052 -
Sensors (Basel, Switzerland) Jul 2023The fingerprint is a widely adopted biometric trait in forensic and civil applications. Fingerprint biometric systems have been investigated using contact prints and...
The fingerprint is a widely adopted biometric trait in forensic and civil applications. Fingerprint biometric systems have been investigated using contact prints and latent and contactless images which range from low to high resolution. While the imaging techniques are advancing with sensor variations, the input fingerprint images also vary. A general fingerprint recognition pipeline consists of a sensor module to acquire images, followed by feature representation, matching and decision modules. In the sensor module, the image quality of the biometric traits significantly affects the biometric system's accuracy and performance. Imaging modality, such as contact and contactless, plays a key role in poor image quality, and therefore, paying attention to imaging modality is important to obtain better performance. Further, underlying physical principles and the working of the sensor can lead to their own forms of distortions during acquisition. There are certain challenges in each module of the fingerprint recognition pipeline, particularly sensors, image acquisition and feature representation. Present reviews in fingerprint systems only analyze the imaging techniques in fingerprint sensing that have existed for a decade. However, the latest emerging trends and recent advances in fingerprint sensing, image acquisition and their challenges have been left behind. Since the present reviews are either obsolete or restricted to a particular subset of the fingerprint systems, this work comprehensively analyzes the state of the art in the field of contact-based, contactless 2D and 3D fingerprint systems and their challenges in the aspects of sensors, image acquisition and interoperability. It outlines the open issues and challenges encountered in fingerprint systems, such as fingerprint performance, environmental factors, acceptability and interoperability, and alternate directions are proposed for a better fingerprint system.
Topics: Biometry; Forensic Medicine
PubMed: 37514887
DOI: 10.3390/s23146591 -
Journal of Cataract and Refractive... Jun 2022To evaluate the effects of phakic intraocular lens (pIOL) implantation on the intraocular lens (IOL) power calculation and subsequently to evaluate the effectiveness of...
Evaluation of impact of posterior phakic IOL implantation on biometry and effectiveness of concomitant use of anterior segment OCT on IOL power calculation for cataract surgery.
PURPOSE
To evaluate the effects of phakic intraocular lens (pIOL) implantation on the intraocular lens (IOL) power calculation and subsequently to evaluate the effectiveness of concomitant use of anterior segment optical coherence tomography (AS-OCT) against biometric changes.
SETTING
Masayuki Ouchi Eye Clinic, Kyoto, Japan.
DESIGN
Prospective consecutive case series.
METHODS
100 patients (100 eyes) who underwent pIOL implantation were enrolled. In each eye, biometry was performed using partial coherence interferometry (PCI) and AS-OCT. Pre-pIOL and post-pIOL implantation IOL power calculation using SRK/T (S), Haigis (H), and Barret Universal II (B) formulas was compared.
RESULTS
100 patients (100 eyes) were included. Anterior chamber depth (ACD) was significantly shorter at post-pIOL implantation for both PCI (P < .001) and AS-OCT (P = .05). When using PCI, the crystalline lens surface was misidentified in 75% of eyes, and in these eyes, the ACD difference between pre-pIOL and post-pIOL implantation exceeded that with both PCI and AS-OCT. The estimated IOL power was significantly lower at post-pIOL implantation according to the H and B formulas (both P < .001) but remained unchanged by the S formula. However, no difference was observed when AS-OCT-derived ACD and lens thickness (LT) values were introduced in the H (P = .16) and B (P = .55) formulas.
CONCLUSIONS
Misidentification of the lens surface occurs in many pIOL-implanted eyes with PCI measurements and could influence the power calculation with H and B formulas while leaving the S formula unaffected. AS-OCT-derived ACD and LT value substitution is recommended for H and B formulas.
Topics: Biometry; Cataract; Humans; Lens, Crystalline; Lenses, Intraocular; Optics and Photonics; Phakic Intraocular Lenses; Prospective Studies; Retrospective Studies; Tomography, Optical Coherence
PubMed: 34486576
DOI: 10.1097/j.jcrs.0000000000000811 -
Scientific Reports Oct 2023Linear biometric measurements on magnetic resonance images are important for the assessment of fetal brain development, which is expert knowledge dependent and...
Linear biometric measurements on magnetic resonance images are important for the assessment of fetal brain development, which is expert knowledge dependent and laborious. This study aims to construct a segmentation-based method for automatic two-dimensional biometric measurements of fetal brain on magnetic resonance images that provides a fast and accurate measurement of fetal brain. A total of 268 volumes (5360 images) magnetic resonance images of normal fetuses were included. The automatic method involves two steps. First, the fetal brain was segmented into four parts with a deep segmentation network: cerebrum, cerebellum, and left and right lateral ventricles. Second, the measurement plane was determined, and the corresponding biometric parameters were calculated according to clinical guidelines, including cerebral biparietal diameter (CBPD), transverse cerebellar diameter (TCD), left and right atrial diameter (LAD/RAD). Pearson correlation coefficient and Bland-Altman plots were used to assess the correlation and agreement between computer-predicted values and manual measurements. Mean differences were used to evaluate the errors quantitatively. Analysis of fetal cerebral growth based on the automatic measurements was also displayed. The experiment results show that correlation coefficients for CBPD, TCD, LAD and RAD were as follows: 0.977, 0.990, 0.817, 0.719, mean differences were - 2.405 mm, - 0.008 mm, - 0.33 mm, - 0.213 mm, respectively. The correlation between the errors and gestational age was not statistically significant (p values were 0.2595, 0.0510, 0.1995, and 0.0609, respectively). The proposed automatic method for linear measurements on fetal brain MRI achieves excellent performance, which is expected to be applied in clinical practice and be helpful for prenatal diagnosis and clinical work efficiency improvement.
Topics: Female; Pregnancy; Humans; Ultrasonography, Prenatal; Biometry; Fetus; Brain; Magnetic Resonance Imaging; Machine Learning
PubMed: 37857681
DOI: 10.1038/s41598-023-43867-4 -
PloS One 2022To investigate modern nonlinear iterative strategies for formula constant optimisation and show the application and results from a large dataset using a set of disclosed...
BACKGROUND
To investigate modern nonlinear iterative strategies for formula constant optimisation and show the application and results from a large dataset using a set of disclosed theoretical-optical lens power calculation concepts.
METHODS
Nonlinear iterative optimisation algorithms were implemented for optimising the root mean squared (SoSPE), the mean absolute (SoAPE), the mean (MPE), the standard deviation (SDPE), the median (MEDPE), as well as the 90% confidence interval (CLPE) of the prediction error (PE), defined as the difference between postoperative achieved and formula predicted spherical equivalent power of refraction. Optimisation was performed using the Levenberg-Marquardt algorithm (SoSPE and SoAPE) or the interior point method (MPE, SDPE, MEDPE, CLPE) for the SRKT, Hoffer Q, Holladay 1, Haigis, and Castrop formulae. The results were based on a dataset of measurements made on 888 eyes after implantation of an aspherical hydrophobic monofocal intraocular lens (Vivinex, Hoya).
RESULTS
For all formulae and all optimisation metrics, the iterative algorithms showed a fast and stable convergence after a couple of iterations. The results prove that with optimisation for SoSPE, SoAPE, MPE, SDPE, MEDPE, and CLPE the root mean squared PE, mean absolute PE, mean PE, standard deviation of PE, median PE, and confidence interval of PE could be minimised in all situations. The results in terms of cumulative distribution function are quite coherent with optimisation for SoSPE, SoAPE, MPE and MEDPE, whereas with optimisation for SDPE and CLPE the standard deviation and confidence interval of the PE distribution could only be minimised at the cost of a systematic offset in mean and median PE.
CONCLUSION
Nonlinear iterative techniques are capable of minimising any statistical metrics (e.g. root mean squared or mean absolute error) of any target parameter (e.g. PE). These optimisation strategies are an important step towards optimising for the target parameters which are used for evaluating the performance of lens power calculation formulae.
Topics: Axial Length, Eye; Biometry; Lens Implantation, Intraocular; Lenses, Intraocular; Optics and Photonics; Phacoemulsification; Refraction, Ocular; Retrospective Studies
PubMed: 35511906
DOI: 10.1371/journal.pone.0267352 -
Journal of Biomedical Optics 2010We report a high-speed, dispersion-encoded, full-range (DEFR) swept-source optical coherence tomography system for in vivo ocular imaging and biometry of small animals....
We report a high-speed, dispersion-encoded, full-range (DEFR) swept-source optical coherence tomography system for in vivo ocular imaging and biometry of small animals. The fast DEFR algorithm removes the depth ambiguity, gives access to objects located at the zero delay position, and doubles the sampling depth to 2x5.0 mm (at -101 to -71 dB sensitivity) in a single scan using 2048 samples/depth scan 0.43 nm line width of a light source operating at 1056 nm with 70 nm tuning range. The acquisition speed (frames of 512 depth scans in 18.3 ms) permits precise on-line monitoring during positioning and provides cross-sectional views of the mouse eye. Preliminary studies demonstrate high-throughput, reproducible assessment of multiple biometric features (e.g., day-to-day reproducibility of axial length measurement +/-5.3 microm) that is insensitive to eye motion sufficient for long-term monitoring.
Topics: Animals; Biometry; Equipment Design; Equipment Failure Analysis; Eye; Lighting; Mice; Ophthalmoscopes; Tomography, Optical Coherence
PubMed: 20799806
DOI: 10.1117/1.3463480