Enhancing Resilience in Biometric Research: Generation of 3D Synthetic Face Data Using Advanced 3D Character Creation Techniques from High-Fidelity Video Games and Animation.

Biometric authentication plays a vital role in various everyday applications with increasing demands for reliability and security. However, the use of real biometric data for research raises privacy concerns and data scarcity issues. A promising approach using synthetic biometric data to address the resulting unbalanced representation and bias, as well as the limited availability of diverse datasets for the development and evaluation of biometric systems, has emerged. Methods for a parameterized generation of highly realistic synthetic data are emerging and the necessary quality metrics to prove that synthetic data can compare to real data are open research tasks. The generation of 3D synthetic face data using game engines' capabilities of generating varied realistic virtual characters is explored as a possible alternative for generating synthetic face data while maintaining reproducibility and ground truth, as opposed to other creation methods. While synthetic data offer several benefits, including improved resilience against data privacy concerns, the limitations and challenges associated with their usage are addressed. Our work shows concurrent behavior in comparing semi-synthetic data as a digital representation of a real identity with their real datasets. Despite slight asymmetrical performance in comparison with a larger database of real samples, a promising performance in face data authentication is shown, which lays the foundation for further investigations with digital avatars and the creation and analysis of fully synthetic data. Future directions for improving synthetic biometric data generation and their impact on advancing biometrics research are discussed.

Customizable Presentation Attack Detection for Improved Resilience of Biometric Applications Using Near-Infrared Skin Detection.

Due to their user-friendliness and reliability, biometric systems have taken a central role in everyday digital identity management for all kinds of private, financial and governmental applications with increasing security requirements. A central security aspect of unsupervised biometric authentication systems is the presentation attack detection (PAD) mechanism, which defines the robustness to fake or altered biometric features. Artifacts like photos, artificial fingers, face masks and fake iris contact lenses are a general security threat for all biometric modalities. The Biometric Evaluation Center of the Institute of Safety and Security Research (ISF) at the University of Applied Sciences Bonn-Rhein-Sieg has specialized in the development of a near-infrared (NIR)-based contact-less detection technology that can distinguish between human skin and most artifact materials. This technology is highly adaptable and has already been successfully integrated into fingerprint scanners, face recognition devices and hand vein scanners. In this work, we introduce a cutting-edge, miniaturized near-infrared presentation attack detection (NIR-PAD) device. It includes an innovative signal processing chain and an integrated distance measurement feature to boost both reliability and resilience. We detail the device's modular configuration and conceptual decisions, highlighting its suitability as a versatile platform for sensor fusion and seamless integration into future biometric systems. This paper elucidates the technological foundations and conceptual framework of the NIR-PAD reference platform, alongside an exploration of its potential applications and prospective enhancements.

Robust Identification and Segmentation of the Outer Skin Layers in Volumetric Fingerprint Data.

Despite the long history of fingerprint biometrics and its use to authenticate individuals, there are still some unsolved challenges with fingerprint acquisition and presentation attack detection (PAD). Currently available commercial fingerprint capture devices struggle with non-ideal skin conditions, including soft skin in infants. They are also susceptible to presentation attacks, which limits their applicability in unsupervised scenarios such as border control. Optical coherence tomography (OCT) could be a promising solution to these problems. In this work, we propose a digital signal processing chain for segmenting two complementary fingerprints from the same OCT fingertip scan: One fingerprint is captured as usual from the epidermis ("outer fingerprint"), whereas the other is taken from inside the skin, at the junction between the epidermis and the underlying dermis ("inner fingerprint"). The resulting 3D fingerprints are then converted to a conventional 2D grayscale representation from which minutiae points can be extracted using existing methods. Our approach is device-independent and has been proven to work with two different time domain OCT scanners. Using efficient GPGPU computing, it took less than a second to process an entire gigabyte of OCT data. To validate the results, we captured OCT fingerprints of 130 individual fingers and compared them with conventional 2D fingerprints of the same fingers. We found that both the outer and inner OCT fingerprints were backward compatible with conventional 2D fingerprints, with the inner fingerprint generally being less damaged and, therefore, more reliable.

Contrast-Enhanced Ultrasound Algorithms (CEUS-LIRADS/ESCULAP) for the Noninvasive Diagnosis of Hepatocellular Carcinoma - A Prospective Multicenter DEGUM Study.

BACKGROUND: This prospective multicenter study funded by the DEGUM assesses the diagnostic accuracy of standardized contrast-enhanced ultrasound (CEUS) for the noninvasive diagnosis of hepatocellular carcinoma (HCC) in high-risk patients. METHODS: Patients at high risk for HCC with a histologically proven focal liver lesion on B-mode ultrasound were recruited prospectively in a multicenter approach. Clinical and imaging data were entered via online entry forms. The diagnostic accuracies for the noninvasive diagnosis of HCC were compared for the conventional interpretation of standardized CEUS at the time of the examination (= CEUS on-site) and the two CEUS algorithms ESCULAP (Erlanger Synopsis for Contrast-enhanced Ultrasound for Liver lesion Assessment in Patients at risk) and CEUS LI-RADS (Contrast-Enhanced UltraSound Liver Imaging Reporting and Data System). RESULTS: 321 patients were recruited in 43 centers; 299 (93.1 %) had liver cirrhosis. The diagnosis according to histology was HCC in 256 cases, and intrahepatic cholangiocarcinoma (iCCA) in 23 cases. In the subgroup of cirrhotic patients (n = 299), the highest sensitivity for the diagnosis of HCC was achieved with the CEUS algorithm ESCULAP (94.2 %) and CEUS on-site (90.9 %). The lowest sensitivity was reached with the CEUS LI-RADS algorithm (64 %; p < 0.001). However, the specificity of CEUS LI-RADS (78.9 %) was superior to that of ESCULAP (50.9 %) and CEUS on-site (64.9 %; p < 0.001). At the same time, the negative predictive value (NPV) of CEUS LI-RADS was significantly inferior to that of ESCULAP (34.1 % vs. 67.4 %; p < 0.001) and CEUS on-site (62.7 %; p < 0.001). The positive predictive values of all modalities were high (around 90 %), with the best results seen for CEUS LI-RADS and CEUS on-site. CONCLUSION: This is the first multicenter, prospective comparison of standardized CEUS and the recently developed CEUS-based algorithms in histologically proven liver lesions in cirrhotic patients. Our results reaffirm the excellent diagnostic accuracy of CEUS for the noninvasive diagnosis of HCC in high-risk patients. However, on-site diagnosis by an experienced examiner achieves an almost equal diagnostic accuracy compared to CEUS-based diagnostic algorithms.

Design of an LED-based sensor system to distinguish human skin from workpieces in safety applications.

Commercial light curtains use a technique known as muting to differentiate between work pieces and other objects (e.g., human limbs) based on precise model knowledge of the process. At manually fed machinery (e.g., bench saws), such precise models cannot be derived due to the way the machinery is used. This paper presents a multispectral scanning sensor to classify an object's surface material as a new approach for the problem. The system is meant to detect the presence of limbs and therefore optimized for human skin detection. Evaluation on a test set of skin and (wet) wood samples showed a sufficiently high reliability with respect to safety standards.

Prophylactic antibiotic treatment in patients with predicted severe acute pancreatitis: a placebo-controlled, double-blind trial.

BACKGROUND & AIMS: Antibiotic prophylaxis in necrotizing pancreatitis remains controversial. Until now, there have been no double-blind studies dealing with this topic. METHODS: A total sample size of 200 patients was calculated to demonstrate with a power of 90% that antibiotic prophylaxis reduces the proportion of patients with infected pancreatic necrosis from 40% placebo (PLA) to 20% ciprofloxacin/metronidazole (CIP/MET). One hundred fourteen patients with acute pancreatitis in combination with a serum C-reactive protein exceeding 150 mg/L and/or necrosis on contrast-enhanced CT scan were enrolled and received either intravenous CIP (2 x 400 mg/day) + MET (2 x 500 mg/day) or PLA. Study medication was discontinued and switched to open antibiotic treatment when infectious complications, multiple organ failure sepsis, or systemic inflammatory response syndrome (SIRS) occurred. After half of the planned sample size was recruited, an adaptive interim analysis was performed, and recruitment was stopped. RESULTS: Fifty-eight patients received CIP/MET and 56 patients PLA. Twenty-eight percent in the CIP/MET group required open antibiotic treatment vs. 46% with PLA. Twelve percent of the CIP/MET group developed infected pancreatic necrosis compared with 9% of the PLA group (P = 0.585). Mortality was 5% in the CIP/MET and 7% in the PLA group. In 76 patients with pancreatic necrosis on contrast-enhanced CT scan, no differences in the rate of infected pancreatic necrosis, systemic complications, or mortality were observed. CONCLUSIONS: This study detected no benefit of antibiotic prophylaxis with respect to the risk of developing infected pancreatic necrosis.

Extracorporeal fibrinogen adsorption--efficacy, selectivity and safety in healthy subjects and patients with foot ulcers.

The elimination of fibrinogen from plasma improves plasma viscosity and whole blood viscosity. For extracorporeal adsorption of fibrinogen the pentapeptide gly-pro-arg-pro-lys was coupled to sepharose CL-4B. Columns containing 100 ml of coupled sepharose CL-4B were used to eliminate fibrinogen from the plasma of 8 healthy male subjects (mean age 27.4 +/- 4.3 years, height 180.9 +/- 8.3 cm, weight 85.1 +/- 13.6 kg). Four treatments were performed in each proband (days 1, 2, 4 and 7). Plasma fibrinogen concentration was lowered from 221.1 +/- 39.0 to 123.5 +/- 21.7 mg/dl (2275 +/- 477 ml plasma treated) by the first treatment, from 172.8 +/- 42.3 to 105.6 +/- 16.5 mg/dl (1609 +/- 761 ml) by the second, from 140.5 +/- 13.8 to 98.8 +/- 8.6 mg/dl (1224 +/- 118 ml) by the third and from 160.2 +/- 23.6 to 106.4 +/- 9.7 mg/dl (1513 +/- 521) by the fourth. Plasma viscosity was improved from 1.40 +/- 0.18 mPa s before the first treatment to 1.23 +/- 0.06 mPa s after fourth treatment, whole blood viscosity from 4.49 +/- 0.36 mPa s to 3.83 +/- 0.27 mPa s (P < 0.01). No clinical side effects and no clinically relevant change of laboratory parameters including in vitro tests on thrombocyte function were observed. Seven men and three women (48-75 years old, 9 patients suffered from diabetes mellitus, one patient from peripheral arterial occlusive disease, 5 patients were on regular hemodialysis) were treated by fibrinogen adsorption. Each column contained 135 ml of coupled sepharose CL-4B. Treatments were scheduled on day 1, 2, 4, 6, 8, 10, 13, 16, 19, 22, 25 and 28. 144 treatments with fibrinogen adsorption were performed. No clinical side effects due to the fibrinogen-adsorption procedure were observed. In these 10 patients the fibrinogen concentration before the first treatment was 473.7 +/- 183.7 mg/dl. In the first treatment session it was lowered to 241.4 +/- 125.8 mg/dl by treating 4270 +/- 1180 ml of plasma. In the following 134 treatments the pre-treatment concentration of fibrinogen was 262.6 +/- 83.4 mg/dl, the post-treatment concentration was 120.6 +/- 37.2 mg/dl. The mean volume of plasma treated was 3737 +/- 1643 ml, the mean duration of a treatment session (except the first treatment) was 143.7 +/- 63.1 min. In 7 patients a mean post-treatment fibrinogen concentration of < or = 123 mg/dl was obtained, in the other patients 133, 177 and 184 mg/dl. Yet, the decrease of fibrinogen concentration was also pronounced in these 3 patients: -82%, -67%, and -73%, respectively. Accelerated wound healing was observed in 9 of the 10 patients. In conclusion, affinity chromatography using the pentapeptide gly-pro-arg-pro-lys is an effective, selective and safe procedure to lower fibrinogen concentration in plasma thereby improving blood viscosity. It could be a therapeutic option in severe blood vessel disease where drug therapy is not sufficient and invasive procedures like bypass or angioplasty cannot be applied.