Handheld terahertz tools for more private security inspections

David A. Zimdars and Irl N. Duling

http://spie.org/newsroom/6465-handheld-terahertz-tools-for-more-private-security-inspections

Single-point terahertz inspection and time-domain terahertz reflection tomography methods are used in a new anomaly detection system that has high detection probabilities and low false alarm rates.

28 May 2016, SPIE Newsroom. DOI: 10.1117/2.1201605.006465

The use of whole-body imagers for enhanced security screening measures has created a number of privacy concerns and involves a high rate of false alarms.1 For instance, even benign objects (e.g., handkerchiefs or boarding passes) that are left in a pocket can trigger false alarms. Although the privacy concerns can be reduced somewhat through the use of automated algorithms,1 the false alarm rate—and the resultant physical pat downs—cannot easily be eliminated.

It has previously been demonstrated that a single-point terahertz inspection tool (also known as a line scan imager) can be used to identify the presence of anomalies during whole-body security imaging.2 Based on their terahertz signature, it is also possible to determine whether such anomalies are benign or whether they pose a threat. Furthermore, time-domain terahertz reflection tomography—a non-contact electromagnetic analog to ultrasound—can be used to generate cross sections of a target structure.2

In this work,2 we have focused on the results of the automated algorithm used in the single-point terahertz inspection method, and on the power of reflection time-domain terahertz reflection tomography, for security applications. As part of these efforts, we have developed a single-point inspection capability into our Picometrix Saf-T-ChekTM terahertz anomaly detection system (ADS). The operation of this system is based on the method of time-domain terahertz reflection tomography. The initial purposes of our ADS have been for security screening of personnel (by domestic or international governments and businesses) and for detection of anomalous items in the head region that may be concealed by religious headgear, wigs, hats, caps, or scarves.3 Our ADS has a minimal equipment footprint, exceptional ease of use, and it is sufficiently lightweight to be portable.

To accomplish this type of inspection, a number of characteristics are required in our terahertz system design. First, the waveform must be collected quickly enough to allow handheld operation. In this study, we thus used a waveform acquisition rate of 100Hz for the single-point inspection tool and 1000Hz for the line scan imaging tool. Our terahertz ADS system (see Figure 1) consists of a handheld inspection wand that is attached—with a lightweight cable—to a portable control unit. In addition, the lens characteristics must be optimized to provide suitable collection efficiency and angular tolerance for handheld operation. It is also necessary for the time delay window to be long enough to accommodate thick head coverings. We use an integrated computer to run a sophisticated artificial intelligence pattern-matching algorithm that automatically judges whether a reflected terahertz pulse sequence is consistent with an anomaly (alarm) or not (clear).

 

Figure 1. Photograph of the Picometrix Saf-T-ChekTMterahertz anomaly detection system (ADS). The control unit is shown on the left, and the handheld inspection tool and storage cradle are shown on the right.

During operation, our terahertz ADS collects and analyzes data that is representative of the cross-sectional dielectric layer structure and dimensions of the targeted area. Permitted materials (e.g., thin cloth layers and skin) in the target have very different patterns than metal objects (e.g., guns or knives) or thicker dielectric objects (which could be a sheet or block of explosives, or a ceramic knife). A list of example anomalies and potential concealments that can be inspected with our system are given in Table 1. At Picometrix, we have performed a series of thorough tests to detect these types of hidden objects and assess the performance of our single-point terahertz ADS. With the use of our automated algorithm, we achieved a probability of detection of more than 90% and a 0% false alarm rate.

Table 1.List of example anomalies and potential concealments that can be detected using the terahertz ADS. C4: Variety of plastic explosive.

Anomalies	Concealments
Sheet explosive	Up to 19 cloth layers
C4	Ski hat
Ceramic knife	Wig
Gun	Baseball hat
Lighter	Turban

To use our ADS, the operator positions the handheld scanner at distance of 1–4 inches from the region that is to be inspected. The ADS handheld scanner is shown in Figure 2, where it is being used to inspect a region of headgear. Once the ADS is correctly positioned, the operator presses the inspection trigger. The system then automatically reports whether the region inspected is clear (green indicators) or is judged to contain an anomaly (red indicators with audible and tactile alarms). The result of the inspection is also indicated on the control unit screen (see Figure 1). This inspection process lasts only a few seconds for each measured point.

 

Figure 2. The ADS handheld scanner being used to inspect headgear.

In summary, we have demonstrated that time-domain terahertz reflection tomography (which can be used to detect the layer structure of non-conducting objects)—when coupled with a suitable detection algorithm—can provide an excellent security detection method. This approach can provide a high probability of detection and low rate of false alarms for screening of headgear at a security checkpoint. It can also be used for secondary screening of anomalies previously detected with a whole-body imager. Our future work will involve the expansion of our automated algorithm to include an expanded list of anomalies. We are also working to continuously improve the ease of use of our terahertz ADS.

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David A. Zimdars, Irl N. Duling

Picometrix, Luna Innovations

Ann Arbor, MI

David Zimdars has been the manager of terahertz research and development since 2001. In this role he is responsible for all terahertz scientific, industrial, and homeland security product development contracts, the commercial T-RayTM2000 analytical/imaging system development, and terahertz manufacturing quality control applications development.

Irl Duling has served as the director of terahertz business development since 2006 and has spearheaded the development of market strategy for Picometrix's terahertz system. He has more than 20 years of experience in the development of products and businesses in high-speed optoelectronics.

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References:

1. M. Grabell, C. Salewski, Sweating bullets: body scanners can see perspiration as a potential weapon, ProPublica, 2011. https://www.propublica.org/article/sweating-bullets-body-scanners-can-see-perspiration-as-a-potential-weapon Accessed 2 May 2016.

2. I. Duling, Handheld THz security imaging. Presented at SPIE Defense + Commercial Sensing 2016.

3. C. Eisenberg, Hats off for TSA; airport screeners authorized to check anyone wearing head gear, News Day, 2007. http://www.aviationpros.com/news/10386129/hats-off-for-tsa-airport-screeners-authorized-to-check-anyone-wearing-head-gear Accessed 18 April 2016

Advanced Photonix / Picometrix files for patent protection on "SYSTEM AND METHOD TO DETECT ANOMALIES"

My Note: Thanks to InvestorVillage poster bucktailjig for providing a link to this patent application. I have reposted only a small portion of the application below. (A link to original filing which contains illustrations, is also found at the bottom of this post.)
http://worldwide.espacenet.com/publicationDetails/description?CC=WO&NR=2013142853A1&KC=A1&FT=D&ND=1&date=20130926&DB=&locale=en_EP

SYSTEM AND METHOD TO DETECT ANOMALIES
BACKGROUND
1. Field of the Invention
[0001] The system and method relates to anomaly detection for detecting anomalous objects on the body of a person.
2. Description of the Known Art
[0002] Computerized tomography ("CT") imaging has been employed for nondestructive examination of various types of articles, such as contraband, which may be hidden inside luggage. However, CT systems emit X-rays, which may pose a health risk to the operators of such systems, as well as passengers who may be standing near the system, and hence CT systems generally include some type of shield to protect the operators and passengers ionizing radiation.
Moreover, although CT systems are capable of analyzing the density of an article, along with other characteristics of the shape and volume of the article, these systems do not have spectroscopic capabilities, and therefore cannot analyze the chemical compositions of the articles. Furthermore, X-rays are not sensitive to the optical traits that result from the article's refractive index and absorption coefficient. These properties, if measurable, can yield unique, high- contrast images and reveal much about the reflective, absorptive and scattering properties of material.
BRIEF SUMMARY
[0003] The system and method to detect anomalies is intended to detect anomalous objects on the body of a person without the need for imaging, and the associated privacy concerns. The primary target area for inspection is the head covered by headwear that was not removed prior to security screening. In addition it is expected that this system could also be used to inspect sensitive areas, such as the chest, groin and buttocks.
[0004] The system is a device that is capable of detecting an anomaly on the body of a person during security screening. An anomaly is defined as any object on any part of the body that is not a natural occurring part of the body and has not been removed during the screening process. The term anomaly is meant to separate the concept of identifying a specific threat (e.g. explosive, gun, etc.) from simply detecting a foreign object on the body that could be a threat.
[0005] This system and method provides for interrogating a point location on the human body and detecting objects under the clothes without the need for imaging. This system and method described includes a hand held portion which will be used to interrogate the suspect location.
[0006] There are up to four primary guidelines that have governed the system and method of operation: (1 ) the system and method are designed to detect anomalies on the body underneath clothing, specifically in the head-region and sensitive areas of the body (groin, buttocks, and breast areas) without violating privacy and religious concerns, (2) the system and method are intended to allow operation by a single screening officer to provide targeted screening of a passenger; (3) the system and method have a small footprint, and is small enough to be portable for screening in areas other than the checkpoint; and (4) the system and method detect a "signature" of the anomaly, which means that the detection occurs without an image or image interpretation. [0007] While it is expected that the system will be deployed at a security checkpoint, the size of the unit and the flexibility of the umbilical connection of the handheld unit will make it compatible with a number of deployment scenarios, such as spot checks at gates, or integration with existing portals. For example, the unit could be deployed on top of an existing portal with the handheld unit available to conduct secondary screening.
[0008] The application for the system and method is the examination of clothing and in particular, religious headwear in a security checkpoint
environment. The unit is portable, and designed to be used by a single operator. The examination is conducted in order to locate sub-surface objects that may constitute a threat as defined later.
[0009] There are up to three primary functional requirements that compose the system and method capability: (1 ) detect anomalies in the head-region possibly concealed by clothing on or off the body; and in particular religious headwear, wigs, hats, caps or scarves - other uses would be to detect anomalies in casts and prosthesis; (2) allow a single screening officer to provide targeted screening of a passenger with minimal equipment footprint, minimal staffing, ease-of-use, and potential portability for screening in areas other than the checkpoint; and (3) perform detection while not tied to an image or image interpretation.
[0010] If a wearer of clothing (such as religious headwear) is designated for inspection, they will be taken aside and examined using the system and method. While this system and method are designed for use in a public checkpoint environment, it is also suitable for any location where standard power is available. The system does not require a fixed installation. It can be relocated to wherever needed.
[0011] The system for detecting anomalies concealed upon a person may include a detection probe having an electromagnetic transmitter and an electromagnetic receiver. The electromagnetic transmitter is configured to emit electromagnetic pulses, while the electromagnetic receiver is configured to sample electromagnetic pulses from the electromagnetic receiver at specified times within a waveform window. The electromagnetic pulses may span the terahertz spectral region of 0.04 to 4 THz. The system may also have optical fibers connected to the electromagnetic transmitter and electromagnetic receiver, wherein femtosecond laser pulses are directed from a source to the
electromagnetic transmitter and the electromagnetic receiver by the optical fibers.
[0012] The system may also include an objective optic incorporated in the detection probe for directing the pulsed electromagnetic radiation through a concealment stack and collecting reflections of the concealment stack at a defined distance. The detection probe may be focused at the depth of concealed skin of the person without the exterior of the detection probe contacting a top of the concealment stack. The transmitter and receiver may then be configured in a monostatic reflection geometry with respect to an objective optic.
[0013] The system may also include a time domain data acquisition system in communication with the receiver. The time domain data acquisition system configured to capture reflections from a range thickness of the concealment stack, the waveform window having the reflection time corresponding to the focus of the objective lens. [0014] The concealment stack over the skin of the person may include clothing or coverings sufficiently small thickness, density or mass, wherein time domain data acquisition system determines the concealment stack to not contain an anomaly or a shield. The clothing or coverings may include natural or synthetic cloth, leather, rubber, vinyl, paper, plastic and/or other thin fibers, sheets or weaves.
[0015] The concealment stack further have one or more intereferent components located at any position within the concealment stack and composed of material of the same type as an anomaly or shield. The time domain data acquisition system is then configured to determine that the intereferent is smaller in volume, density, or mass than a threshold value to be considered an anomaly. The concealment stack further include one or more anomaly placed at any level within the concealment stack, where the anomaly is an object of greater thickness, lateral extent, volume, density, or mass than a threshold value.
[0016] The time domain data acquisition system may be configured to choose a quantitative threshold for thickness, lateral extent; volume, density, or mass to be considered an anomaly by scaling thresholds to electromagnetic properties of the anomaly material in comparison to a benign material in the concealment stack and evaluating the measurement from the system as an anomaly when the waveform contains one or more features indicating that an object within the concealment stack exceeds the scaled thresholds.
[0017] The system may also include a light source that projects an illuminated pattern onto the concealment stack on the person under test indicating a region of inspection. [0018] The system may also have a compensator located between the source and the electromagnetic transmitter or electromagnetic receiver, wherein the compensator compensates the pulses so that the pulses are sufficiently short at the electromagnetic transmitter or electromagnetic receiver. The compensator may be a grating sequence, a prism sequence, a grism sequence, a fiber bragg grating, or anomalous dispersion fiber.
[0019] The system may also have a sensor connected to the detection probe, wherein the sensor is configured to provide coordinates of the detection probe's position in one or more dimensions of space or angle. Additionally or
alternatively, the sensor may be configured to detect in a different modality than the waveforms reflected from the concealment stack and interrogate a
substantially same region of concealment stack on the person.
[0020] The system may also include a secondary transmitter connected to the detection, wherein the secondary transmitter if configured to emit alpha, beta, x- ray, or gamma rays.
Read the remainder of the patent here:
http://worldwide.espacenet.com/publicationDetails/originalDocument?CC=WO&NR=2013142853A1&KC=A1&FT=D&ND=1&date=20130926&DB=&locale=en_EP

Advanced Photonix (API) makes sales in Terahertz/NDT of $11.4 million in fiscal 2013

Advanced Photonix while reporting a rather dismal year overall, due primarily to supply chain problems in their high speed optical receivers market, showed remarkable growth for the year in THz sales.

"Industrial sensing and non-destructive test market revenues were $11.4 million in fiscal 2013, an increase of 6% or $631,000 from the fiscal 2012 revenue, up from $10.8 million. Our industrial sensing and non-destructive test revenue in the fourth quarter of the current year increased 47% or $1.2 million from the comparable prior year quarter. These increases are the result of higher terahertz contract and system sales, as well as approximately $298,000 in revenue from 1 month of activity with the net operating assets of Silonex, which was acquired by our Advanced Photonix Canada subsidiary."
Rob Risser stated:
"The terahertz product platform grew due to substantial contract revenue. In addition, our terahertz product platform concentrated on application development to support our developing value-added reseller channel and improving product reliability in order to support the demand in process control market requirements of operating 24/7, 365 days of the year. The good news is that our telecom revenue bottomed in the fourth quarter and is growing again as we enter fiscal 2014 as the supply chain issues are resolved."
" The terahertz product platform spent the year completing several contracts for applying terahertz to the F-35 Joint Strike Fighter jet platform. Developing the industrial process control value-added reseller channel and improving terahertz reliability in our T-Gauge product offering in order to address the industrial process and quality control requirements. This year marks the transition for the terahertz product platform as a research and -- as research and development moderates and contract revenue declines, which should be offset by industrial and laboratory market product sales increases."
Rick Kurtz added: "The world economy is starting to show enough growth to spur manufacturing investment. We introduced our fifth generation terahertz system, T-Gauge 5000 product line, specifically for this market. We're also in the process of attaining both UL and CE certification, and will be the only time-domain terahertz product in the world with such certification."

The only disappointing news was that the TSA approval of the anomaly detection device, Saf-T-Chek,slated for inclusion on the airport qualified providers list,(QPL), remains on hold. Looks like 2014 could be the break-out year for API.

Seeking Alpha,mentions/ links to this blog, in article- Gun Control, 3-D Printing And Airport Security - The Coming Age Of Terahertz

My Note: Seeking Alpha is a well known, investment newsletter, which today features a story about Terahertz, and suggests that Advanced Photonix (API), is one company to consider if one is looking to invest in THz. Some links in the article link to this blog and there is also a reference to the "Terahertz Blog". Pretty cool! As always this is not investment advice on my part, and do your own due diligence. (I do note, that it's pretty clear, Digital Barriers is the most probable supplier of the NYPD, THz, scanner).
http://seekingalpha.com/article/1137851-gun-control-3-d-printing-and-airport-security-the-coming-age-of-terahertz?source=google_news

                                                                                  Contributor:   BuySellShort

A new technology called Terahertz could give investors exposure to many of the hot sectors in the news right now. Gun control, 3-D printing and airport security are areas where investors can see nice returns this year. We will focus on the detection aspect but also mention the other sectors.

Gun control and the detection of illegal weapons have been front and center in the media since the tragedy at Newtown. Gun control will be a hard sell even after this tragedy, so the push to place blame and attention to other gun control initiatives will be strong. Firearm manufacturers such as Smith and Wesson (SWHC) garner much of the attention, but there are of course other angles to look at. Detection devices may give both sides something to agree on.

This Sunday on Face The Nation, New York City Police Commissioner Ray Kelly talked about a new technology to detect illegal guns. It is a device that looks similar to body scanners at airports that reads Terahertz - a specific form of natural energy emitted by people and virtually all forms of matter. No company has been specifically mentioned as developing this scanner but there are only two companies that come to mind, USA based Advanced Photonix Inc. (API) and Digital Barriers, (DGB) a company based in the United Kingdom. Traders should note that over the last month, Advanced Photonix has seen its share price increase 60% as theNew York Police Department has been trialing this gun detection tool. The Terahertz Blog even mentions Advanced Photonix in this context.

Advanced Photonix Inc., is a small cap stock traders should keep a close eye on in the coming weeks. The company is a leading supplier of opto-electronic solutions and Terahertz sensors and instrumentation to a global OEM customer base. The terahertz sensor product line is targeted to the Nondestructive Testing (including Baggage/Cargo Scanning) and Quality Control markets. Markets they are focused on include telecom, homeland security, military and industrial. On its website Advanced Photonix specifically mentions "weapons and explosives detection for Homeland Security and Defense markets" as its applications of focus.

Homeland Security conference. At the event Richard Kurtz with Advanced Photonix wrapped a plastic knife blade a few folds into a cloth before pointing a flashlight-like device at the cloth. Nearby, a screen flashed the word "anomaly" in large red lettersHomeland Security conference. At the event Richard Kurtz with Advanced Photonix wrapped a plastic knife blade a few folds into a cloth before pointing a flashlight-like device at the cloth. Nearby, a screen flashed the word "anomaly" in large red letters

In May of last year, Advanced Photonix showed off their threat detection device called the Saf-T-Chek Anomaly Detection System at the annualHomeland Security conference. At the event Richard Kurtz with Advanced Photonix wrapped a plastic knife blade a few folds into a cloth before pointing a flashlight-like device at the cloth. Nearby, a screen flashed the word "anomaly" in large red letters.

Aside from this detection application Advanced Photonix can be viewed as a possible player in the 3-D market. Stocks with any hint of 3-D have seen their stock prices soar in recent days. On Friday Comatron Ltd, (CIMT) a CAD software company saw its stock price gain 20% when it was linked as a possible play on 3-D printing. Organovo Holdings (ONVO.PK) has seen its stock price double in recent days as traders focused on its 3-D applications. Perceptron, Inc's (PRCP) stock price has moved 40% over the last three weeks simply because it has the words 3-D on its website. The company develops a 3-D sensor much like the applications of Advanced Photonix.
Advanced Photonix could see a lot of investor interest on news of the NYPD rolling out Terahertz gun detection. Though it is unlikely any meaningful gun control comes to pass, what is more likely is a push for new passive technologies to help alleviate threats. As a major player in this new sector, there appears to be significant upside potential for Advanced Photonix's business. There is also the possibility of gaining attention in the 3-D mania ongoing right now. Additionally, last week the TSA announced it is removing the controversial X-ray scanners from airports. This too could be a boon for Advanced Photonix and its Terahertz scanners. There is much to like with this company and investors should spend some more time researching. Whether or not Advanced Photonix is proved to be the company being considered by the NYPD, being a major player in a very small and new business should be good. The upside both for Advanced Photonix's business and in turn stock price could be nice!

Advanced Photonix (API), provides corporate update

My Note: I attach a link to  Advanced Photonix, corporate update from November, 2012.  It has some interesting information regarding the growing commercial application for Terahertz that API is tapping into. I have tried to link the PDF file here, but for some reason, I can't get it loaded. 
However, I can link to the Investors Village post, which contains the PDF, which readers here can then access. 
http://www.investorvillage.com/smbd.asp?mb=4804&mn=19952&pt=msg&mid=12436820

Some highlights of the update in regard to THz, at API:
API is in it's 5th generation THz system, employing the T-Gauge in 2010, which is targeted at Industrial Process Control. API has invested over $30 million dollars in THz research & development over 11 years with more than 35 patents and patents pending. The T-Gauge system allows for continuous manufacturing applications, and is currently being used on factory floors where paper, plastics, shingles, flat roofs and walkways are being manufactured, and where tight process control is essential.
The T-Gauge is also replacing conventional nuclear gauges. It notes it current customers are Fortune 500 companies. (The following is my best effort to convey the "flavor" of some aspects of the update using pictures either I was able to recapture from earlier PDF's or which were sent to me, by a fellow API investor, who shall remain anonymous, but goes by the moniker of   bucktailjig05. Please review the actual update, as this is just a crude effort to give readers a sense about it.                                      

The update also notes that the Quality and Process Control Market for Terahert, has a Total Addressable Market (TAM),  growing to 100 million dollars with API focusing on the following areas:

-Aerospace (TAM growing to $20 million) with work on the 
     -F-35 QC (potential 15 systems)

          -Coating measurements- Stealth coating                               
          -Step and gap measurements
Industrial Process Control (TAM growing to $80 million dollars)
     -Continuous manufacturing (TAM growing to $50M)
            -Nuclear gauge replacement
            -Multiple measurements for process control
     -Automotivve (TAM 10M)
             -Fuel Tank thickness measurements

     -Paper (TAM $10M) 
     -Package product inspection (TAM $10M)
           -Pharmaceuticals, consumer goods

Security (TAM growing to $80M)
     -Baggage/package screening
     -Personnel screening

The update also notes that API has established a worldwide distribution system using Value Added Resellers-VARs

It concludes by noting that commercial acceptance of the anomaly detection system, has Homerun potential in the security market. (This product is named the Saf-T-Chek)

Advanced Photonix makes advances with it's Terahertz applications the T-Gauge, F-35 product line, and moves it's anomaly detection system into non-airport market

My Note: On November 13th, 2012 Advanced Photonix held a conference call for listeners.
Here are some of the highlights:
The company announced that a record number of it's T-Gauge systems would be shipped in the 3rd Quarter for factory installation. COO Rob Risser indicated that API is beginning to get market traction in the industrial sensing sector with the early adopters of THz based sensing technology finding multiple uses for the T-Gauge. The company anticipates a steady growth of sales in the second half of the year.

CEO Rick Kurtz, indicated that the company is completing several F-35 contracts, (which appears to coincide with recent press about the delivery of the first F-35's to the Marines. http://www.sacbee.com/2012/11/20/5001044/lockheed-martin-delivers-three.html 
Rick also indicated that the goal is to fully commercialize the products which have been developed for use by API in the F-35 program for the companies domestic and international partners. 

Rob indicated that the companies anomaly detection system which it calls the Saf-T-Chek, has been evaluated by both the TSA, and In-Q-Tel, and was "well received". This month, the company is finalizing additional software improvements to the automated algorithm system, contained in the product, and anticipates that it will then be eligible to be placed on the intermodal transportation list, for use of the Saf-T-Chek, for a number of potential non-airport applications. It was interesting to hear that the company anticipates that FEMA will fund the development of this use. 

Use of the Saf-T-Chek, will requires a more rigorous qualification process before the product can be placed on the airport qualified equipment list, and is anticipated to be more than a year away. 

Overall, Rob expressed that the companies THz applications will be lower cost, and that the list of qualifed Value added resellers of the products continues to grow domestically and internationally, with an increasing sophistication in understanding how the companies THz applications are useful in  filling  a number of niche applications and markets.
 These of course, are my interpretations of what I heard listening to the conference call. Please listen for yourselves, to formulate your own understanding.