The Container Screening Device (CSD) is a portable, benchtop measurement system for real-time sealed-container inspection, and content (liquid/ material) classification and discrimination. The technology uses sound waves to acoustically detect, classify, and discriminate threat versus non-threat substances and materials such as liquid explosives, hazardous and flammable liquids, and other caustic or dangerous liquids at security checkpoints. The CSD originally was designed as a prototype for both field measurements and bench-top applications for liquid forensics, intelligence, and law enforcement scenarios.

Side view of the Container Screening Device prototype.

The CSD checks for materials that can be used to build weapons of mass destruction, concealed contraband, and illegal substances, and identifies fraudulently labeled containers. It can also be employed in manufacturing environments to ensure the correct labeling of products, to detect foreign objects, or by first responders in emergency situations for noninvasive and nondestructive detection of dangerous substances.

Other technologies such as X-rays often require highly trained personnel and safety measures to be put in place, are quite expensive or bulky, or are inadequate for effective classification or identification of liquid contents. They also are impractical for immediate response scenarios. This versatile tool can rapidly screen bulk containers ranging in size from a 5-gallon container to test-tube-sized containers in the field. In addition, this technology could easily be modified to accommodate the inspection and examination of larger containers (e.g., 55-gallon drums). The CSD significantly reduces the amount of time required to screen such containers at checkpoints, while at the same time increasing the reliability and accuracy of the screenings.

The CSD classification and identification capabilities are based upon comparing a suite of measured acoustic properties (or signatures) of a liquid against pre-characterized, temperature-compensated profiles in the acoustic properties database on the device. Additional capabilities include an automated container distance and temperature measurement, and automated gain function. Current efforts are underway to design and test automatic accommodation for wall thickness and wall material of the container being tested. Also, the signal processing and computational algorithms employed by the CSD are being modified to more effectively correct for acoustic reflection and transmission coefficients in various wall materials. This will significantly improve the consistency and accuracy of information gathered during screening, and will provide for a much wider capability for discriminating liquids than other available technologies.

This platform is currently capable of acquiring additional acoustic property “signatures” such as acoustic impedance, density, acoustic resonance features, acoustic absorption spectra, and more. Finally, non-acoustic physical sensors may be deployed to obtain additional (orthogonal) data to further increase accuracy and sensitivity.

For more information, contact Kannan Krishnaswami at This email address is being protected from spambots. You need JavaScript enabled to view it.; 509-375-4597.


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This article first appeared in the September, 2017 issue of Tech Briefs Magazine.

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