Test Methods to Rigorously, Reproducibly, and Accurately Measure the Detection Performance of Walk-through Metal Detectors.

Walk-through metal detectors (WTMDs) are the primary tool for the detection of concealed metal contraband and threat items on a person. They are found at almost all security checkpoint stations worldwide. It is important for security that assessing the detection performance of WTMDs is done rigorously, accurately, and reproducibly.

Predicting Detection Performance on Security X-Ray Images as a Function of Image Quality.

Developing methods to predict how image quality affects the task performance is a topic of great interest in many applications. While such studies have been performed in the medical imaging community, little work has been reported in the security X-ray imaging literature. In this paper, we develop models that predict the effect of image quality on the detection of the improvised explosive device components by bomb technicians in images taken using portable X-ray systems.

The IEEE TC-10 Standards: Update 2019.

There is a global need to standardize the terms and the test and computational methods that are used to describe and/or measure the parameters that characterize and define the performance of devices that generate signals and subsequently measure and analyze the waveforms acquired of those signals. This standardization is essential for accurate, reproducible, reliable, and communicable characterization of the performance of these devices, which supports technology and product advancement, product comparison and performance tracking, and device calibration and traceability. Users of the devices need to unambiguously specify the device performance required for particular applications.

Multivariate Statistical Approach to Image Quality Tasks.

Many existing Natural Scene Statistics-based no reference image quality assessment (NR IQA) algorithms employ parametric distributions to capture the statistical inconsistencies of bandpass distorted image coefficients. Here we propose a model of natural image coefficients expressed in the bandpass spatial domain that has the potential to capture higher-order correlations that may be induced by the presence of distortions. We analyze how the parameters of the multivariate model are affected by different distortion types, and we show their ability to capture distortion-sensitive image quality information.

Testing the Image Quality of Cabinet X-ray Systems for Security Screening: The Revised ASTM F792 Standard.

ASTM F792, provides test objects and methods for measuring the imaging performance of cabinet X-ray systems used at security checkpoints. The standard is widely used, with many thousands of ASTM F792 test objects utilized throughout the world. The last major revision of the standard was more than 15 years ago (2001), and since that time, several deficiencies have been noted when using the standard for testing modern systems employing multiple-view and multiple-energy configurations.

Improved Threat Identification Using Tonemapping of High-Dynamic-Range X-ray Images.

Transmission X-ray systems are used to image the contents of suspicious packages, luggage, and cargo. The images can have a dynamic range of 1,000:1 or greater, but are typically displayed on consumer-grade displays with a low-dynamic range of less than 255:1. We show that modern tonemapping algorithms can greatly improve the process of displaying X-ray images on low-dynamic-range displays and compare the performance of some popular algorithms for this purpose.

Method for Measuring the Phase Spectrum of the Output of a Frequency Source Used in the Calibration of an Electroshock Weapon Characterization System.

Electroshock weapons (ESWs) output a transient burst of impulse-like high-voltage electrical signals that can incapacitate a human target. To ensure safe and effective operation of ESW, their outputs must be accurately measured. Accordingly, the systems used to measure the output of an ESW must be accurately characterized, and their response functions must be known for subsequent processing of the ESW output waveforms (current and high voltage).

Test Object for Accurate and Reproducible Measurement of the Detection Response of Hand-worn and Hand-held Metal Detectors.

The assessment of the detection performance of metal detectors (hand-worn, hand-held, and walk-through models) is based on the ability of the detectors to sound an alarm when presented with a test object. These test objects are typically actual threat items or simulated threat items. The orientation of these test objects with the magnetic field generated by the metal detectors may affect the detectability of the test objects.

Test Methods for Measuring the Electrical Output of Electroshock Weapons.

Electroshock weapons (ESWs) have become a ubiquitous component of weapons used in the arsenal of domestic law enforcement (LE) agencies and the military around the world. It is a major contributor to the escalation of force policies and procedures of many LE agencies. ESWs function by providing a high-voltage low-current electrical shock that, when discharged into a live (typically human) target, can temporarily incapacitate that target.

Tasking on Natural Statistics of Infrared Images.

Natural scene statistics (NSSs) provide powerful, perceptually relevant tools that have been successfully used for image quality analysis of visible light images. Since NSS capture statistical regularities that arise from the physical world, they are relevant to long wave infrared (LWIR) images, which differ from visible light images mainly by the wavelengths captured at the imaging sensors. We show that NSS models of bandpass LWIR images are similar to those of visible light images, but with different parameterizations.

Calibration of Speed Enforcement Down-The-Road Radars.

We examine the measurement uncertainty associated with different methods of calibrating the ubiquitous down-the-road (DTR) radar used in speed enforcement. These calibration methods include the use of audio frequency sources, tuning forks, a fifth wheel attached to the rear of the vehicle with the radar unit, and the speedometer of the vehicle. We also provide an analysis showing the effect of calibration uncertainty on DTR-radar speed measurement uncertainty.

Nanosecond delay with subpicosecond uncertainty.

We have combined a commercially available, variable-length coaxial delay line (trombone line) with a high-resolution linear translation system. The result is better resolution and lower uncertainty in the achievable delays than previously available. The range of delay is 0 ps to approximately 1250 ps, the bidirectional resolution is 2.