Previous projects of Steve Smith and
Spectrum San Diego, Inc.
The SECURE 1000 is a back-scatter x-ray system for detecting weapons and contraband hidden under
persons' clothing. The person being screened stands next to the system for a three second
front scan, and then turns around for a three second rear scan. Almost immediately, an image
of the person and any concealed objects appears on the monitor. Metal guns and knifes can
be detected, as well as nonmetallic objects such as drugs and explosives. About 40 of these
$100k systems have been sold in the last five years, mainly for screening visitors entering
prisons and at Customs checkpoints. The engineers at Spectrum San Diego were solely
responsible for the design of this product, from initial research into the feasibility
of the technique to overseeing the manufacturing. More information is available at
the SECURE 1000 page.
The SECURE 2000 is similar to the SECURE 1000, but covertly scans persons for hidden weapons and explosives as they walk down a hallway. Four images are acquired of each subject as they walk at normal speed through the corridor, without the subjects being aware that they are being searched. The SECURE 2000 was developed under a $600k contract from an overseas
country to protect a presidential palace against terrorist attacks. The engineers at Spectrum San Diego were solely responsible for the design of this product, from initial research into the feasibility of the approach, to fabrication of the prototype, and installation of the system.
In 1998 through 1999, the engineering team at Spectrum San Diego designed an x-ray baggage scanner, similar to those currently being used in airports. This work was conducted under a $650k contract awarded from a private U.S. company. This project involved the ground-up design of a 160 KV x-ray source, a 160 KV power supply, a dual-energy linear array detector, software for the detection of explosives in luggage, and integration with the mechanical baggage conveyer.
Pulsed X-ray Dosimeter
During 1999, Spectrum San Diego developed a new technique for measuring the radiation output of high-power pulsed x-ray sources. These x-ray sources are used by the air force and other groups to simulate the effects of nuclear blasts, and typically involve doses of 10,000 Rads, exposing a 50x50 cm area, delivered in 50 nsec. The work by Spectrum San Diego showed the feasibility of measuring this x-ray pulse with a temporal resolution of 2-5 nsec, a spatial resolution of 5-8 mm, and an energy resolution of 20%, simultaneously. This project was supported by the United States air force under a $100k research contract.
X-ray imaging is widely used in printed circuit board inspection to verify the quality of
the solder connections. However, solder joints can be on both the top and bottom sides
of a PCB, making them appear superimposed in an x-ray image. While director of
research at IRT corporation in 1992-93 (now called Nicolet Imaging Systems), Dr. Smith developed
the imaging hardware and associated algorithms for a tomosynthesis (3D) x-
ray imaging system. This product acquires 6-10 images of each solder joint at various
angles, and then reconstructs separate images of the two sides of the PCB. About 10 of
these $400,000 systems are in use throughout the world. The engineer's now at Spectrum San
Diego designed the x-ray source, the x-ray detector, the calibration method, and the
reconstruction algorithms for this system.
Bottle and Can Inspection
In 1995, Dr. Smith assisted Thermedics
Detection in the design of a flexible x-ray imaging system for inspecting cans and
bottles on the fill line. While using very low levels of radiation, the InScan XR-100 can accurately determine the fill level, detect leaks, screen for foreign objects, and identify unacceptable containers. Approximately 100 of these systems have been sold to the beer and beverage industry. The InScan XR-100 sells for about $25,000.
Bone densitometry measures the amount of calcium in a patient's spine (and other
bones), a critical step in the detection and treatment of osteoporosis. One of the most
advanced techniques is Dual Energy X-ray Absorptometry (DEXA), combining information from x-ray
images taken at different energies. DEXA provides bone measurements with better than
1% precision, in spite of having to measure the bone through varying thicknesses of soft
tissue. An examination takes about 5 minutes, with the patient resting on an
examination table. Approximately 500 DEXA scanners have been sold worldwide, with a
list price of about $70,000. Dr. Smith participated in the development of DEXA in
1987-89, while director of research at Lunar
Radiation Corporation, a leader in dual energy imaging.
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