No abstract

For more than a decade, Midwest Research Institute (MRI) has investigated the effects of exposure to 60 Hz electric and magnetic fields (EMF) on human physiology, performance, and biochemistry. This accumulated experience, new research directions, and limited resources made it important to design more comprehensive and operationally cost‐effective exposure facilities. Here we describe the new, integrated laboratory exposure test facilities recently constructed at MRI and present data on relevant characteristics of the exposure systems. Concentric coil systems were developed to generate uniform magnetic fields within the three new exposure rooms, with rapid cancellation of the field to ambient levels in the rest of the laboratory. Control systems are fully automated, computer‐based, and independent. These provide the operational flexibility needed to present fields of different magnitudes, frequencies, and polarization. The local geomagnetic field can be modulated and/or canceled, and both AC and DC fields can be presented in various combinations. Capabilities for conducting double‐blind experiments with true active‐sham exposure conditions were implemented using bifilar windings and applying current flow in the opposite direction for each wire in a pair. The new facilities provide a comprehensive capability for laboratory‐based human research on the potential effects of exposure to AC and DC magnetic fields. Bioelectromagnetics 20:101–111, 1999. © 1999 Wiley‐Liss, Inc.

No abstract

Directional pyramidal filter banks as feature extractors for ocular vascular biometrics are proposed. Apart from the red, green, and blue (RGB) format, we analyze the significance of using HSV, YCbCr, and layer combinations (R+Cr)/2, (G+Cr)/2, (B+Cr)/2. For classification, Linear Discriminant Analysis (LDA) is used. We outline the advantages of a Contourlet transform implementation for eye vein biometrics, based on vascular patterns seen on the white of the eye. The performance of the proposed algorithm is evaluated using Receiver Operating Characteristic (ROC) curves. Area under the curve (AUC), equal error rate (EER), and decidability values are used as performance metrics. The dataset consists of more than 1600 still images and video frames acquired in two separate sessions from 40 subjects. All images were captured from a distance of 5 feet using a DSLR camera with an attached white LED light source. We evaluate and discuss the results of cross matching features extracted from still images and video recordings of conjunctival vasculature patterns. The best AUC value of 0.9999 with an EER of 0.064% resulted from using Cb layer in YCbCr color space. The best (lowest value) EER of 0.032% was obtained with an AUC value of 0.9998 using the green layer of the RGB images.

No abstract