Entries Tagged "sensors"

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Quantum Ghost Imaging

This is cool:

Ghost imaging is a technique that allows a high-resolution camera to produce an image of an object that the camera itself cannot see. It uses two sensors: one that looks at a light source and another that looks at the object. These sensors point in different directions. For example, the camera can face the sun and the light meter can face an object.

That object might be a soldier, a tank or an airplane, Ron Meyers, a laboratory quantum physicist explained during an Oct. 28 interview on the Pentagon Channel podcast “Armed with Science: Research and Applications for the Modern Military.”

Once this is done, a computer program compares and combines the patterns received from the object and the light. This creates a “ghost image,” a black-and-white or color picture of the object being photographed. The earliest ghost images were silhouettes, but current ones depict the objects more realistically.

[…]

Using virtually any light source—from a fluorescent bulb, lasers, or even the sun—quantum ghost imaging gives a clearer picture of objects by eliminating conditions such as clouds, fog and smoke beyond the ability of conventional imaging.

EDITED TO ADD (12/12): A better explanation of the effect, and a detailed paper.

Posted on November 18, 2009 at 6:22 AM • View Comments

The Doghouse: ADE 651

A divining rod to find explosives in Iraq:

ATSC’s promotional material claims that its device can find guns, ammunition, drugs, truffles, human bodies and even contraband ivory at distances up to a kilometer, underground, through walls, underwater or even from airplanes three miles high. The device works on “electrostatic magnetic ion attraction,” ATSC says.

To detect materials, the operator puts an array of plastic-coated cardboard cards with bar codes into a holder connected to the wand by a cable. “It would be laughable,” Colonel Bidlack said, “except someone down the street from you is counting on this to keep bombs off the streets.”

Proponents of the wand often argue that errors stem from the human operator, who they say must be rested, with a steady pulse and body temperature, before using the device.

Then the operator must walk in place a few moments to “charge” the device, since it has no battery or other power source, and walk with the wand at right angles to the body. If there are explosives or drugs to the operator’s left, the wand is supposed to swivel to the operator’s left and point at them.

If, as often happens, no explosives or weapons are found, the police may blame a false positive on other things found in the car, like perfume, air fresheners or gold fillings in the driver’s teeth.

Complete quackery, sold by Cumberland Industries:

Still, the Iraqi government has purchased more than 1,500 of the devices, known as the ADE 651, at costs from $16,500 to $60,000 each. Nearly every police checkpoint, and many Iraqi military checkpoints, have one of the devices, which are now normally used in place of physical inspections of vehicles.

James Randi says:

This Foundation will give you our million-dollar prize upon the successful testing of the ADE651® device. Such test can be performed by anyone, anywhere, under your conditions, by you or by any appointed person or persons, in direct satisfaction of any or all of the provisions laid out above by you.

No one will respond to this, because the ADE651® is a useless, quack, device which cannot perform any other function than separating naïve persons from their money. It’s a fake, a scam, a swindle, and a blatant fraud. The manufacturers, distributors, vendors, advertisers, and retailers of the ADE651® device are criminals, liars, and thieves who will ignore this challenge because they know the device, the theory, the described principles of operation, and the technical descriptions given, are nonsense, lies, and fraudulent.

And he quotes from the Cumberland Industries literature (not online, unfortunately):

Ignores All Known Concealment Methods. By programming the detection cards to specifically target a particular substance, (through the proprietary process of electro-static matching of the ionic charge and structure of the substance), the ADE651® will “by-pass” all known attempts to conceal the target substance. It has been shown to penetrate Lead, other metals, concrete, and other matter (including hiding in the body) used in attempts to block the attraction.

No Consumables nor Maintenance Contracts Required. Unlike Trace Detectors that require the supply of sample traps, the ADE651® does not utilize any consumables (exceptions include: cotton-gloves and cleanser) thereby reducing the operational costs of the equipment. The equipment is Operator maintained and requires no ongoing maintenance service contracts. It comes with a hardware three year warranty. Since the equipment is powered electro statically, there are no batteries or conventional power supplies to change or maintain.

One interesting point is that the effectiveness of this device depends strongly on what the bad guys think about its effectiveness. If the bad guys think it works, they have to find someone who is 1) willing to kill himself, and 2) rational enough to keep his cool while being tested by one of these things. I’ll bet that the ADE651 makes it harder to recruit suicide bombers.

But what happened to the days when you could buy a divining rod for $100?

EDITED TO ADD (11/11): In case the company pulls the spec sheet, it’s archived here.

Posted on November 6, 2009 at 6:55 AM •

Detecting Terrorists by Smelling Fear

Really:

The technology relies on recognising a pheromone – or scent signal – produced in sweat when a person is scared.

Researchers hope the ”fear detector” will make it possible to identify individuals at check points who are up to no good.

Terrorists with murder in mind, drug smugglers, or criminals on the run are likely to be very fearful of being discovered.

Seems like yet another technology that will be swamped with false positives.

And is there any justification to the hypothesis that terrorists will be more afraid than anyone else? And do we know why people tend to feel fear? Is it because they’re up to no good, or because of more benign reasons—like they’re scared of something? This link from emotion to intent is very tenuous.

Posted on November 3, 2009 at 6:12 AM • View Comments

Software Problems with a Breath Alcohol Detector

This is an excellent lesson in the security problems inherent in trusting proprietary software:

After two years of attempting to get the computer based source code for the Alcotest 7110 MKIII-C, defense counsel in State v. Chun were successful in obtaining the code, and had it analyzed by Base One Technologies, Inc.

Draeger, the manufacturer maintained that the system was perfect, and that revealing the source code would be damaging to its business. They were right about the second part, of course, because it turned out that the code was terrible.

2. Readings are Not Averaged Correctly: When the software takes a series of readings, it first averages the first two readings. Then, it averages the third reading with the average just computed. Then the fourth reading is averaged with the new average, and so on. There is no comment or note detailing a reason for this calculation, which would cause the first reading to have more weight than successive readings. Nonetheless, the comments say that the values should be averaged, and they are not.

3. Results Limited to Small, Discrete Values: The A/D converters measuring the IR readings and the fuel cell readings can produce values between 0 and 4095. However, the software divides the final average(s) by 256, meaning the final result can only have 16 values to represent the five-volt range (or less), or, represent the range of alcohol readings possible. This is a loss of precision in the data; of a possible twelve bits of information, only four bits are used. Further, because of an attribute in the IR calculations, the result value is further divided in half. This means that only 8 values are possible for the IR detection, and this is compared against the 16 values of the fuel cell.

4. Catastrophic Error Detection Is Disabled: An interrupt that detects that the microprocessor is trying to execute an illegal instruction is disabled, meaning that the Alcotest software could appear to run correctly while executing wild branches or invalid code for a period of time. Other interrupts ignored are the Computer Operating Property (a watchdog timer), and the Software Interrupt.

Basically, the system was designed to return some sort of result regardless.

This is important. As we become more and more dependent on software for evidentiary and other legal applications, we need to be able to carefully examine that software for accuracy, reliability, etc. Every government contract for breath alcohol detectors needs to include the requirement for public source code. “You can’t look at our code because we don’t want you to” simply isn’t good enough.

Posted on May 13, 2009 at 2:07 PM • View Comments

Sniffing Keyboard Keystrokes with a Laser

Interesting:

Chief Security Engineer Andrea Barisani and hardware hacker Daniele Bianco used a handmade laser microphone device and a photo diode to measure the vibrations, software for analyzing the spectrograms of frequencies from different keystrokes, as well as technology to apply the data to a dictionary to try to guess the words. They used a technique called dynamic time warping that’s typically used for speech recognition applications, to measure the similarity of signals.

Line-of-sight on the laptop is needed, but it works through a glass window, they said. Using an infrared laser would prevent a victim from knowing they were being spied on.

Another article.

Posted on March 25, 2009 at 6:59 AM • View Comments

Research in Explosive Detection

Interesting:

Much of this research focuses on “micromechanical” devices—tiny sensors that have microscopic probes on which airborne chemical vapors deposit. When the right chemicals find the surface of the sensors, they induce tiny mechanical motions, and those motions create electronic signals that can be measured.

These devices are relatively inexpensive to make and can sensitively detect explosives, but they often have the drawback that they cannot discriminate between similar chemicals—the dangerous and the benign. They may detect a trace amount of TNT, for instance, but they may not be able to distinguish that from a trace amount of gasoline.

Seeking to make a better micromechanical sensor, Thundat and his colleagues realized they could detect explosives selectively and with extremely high sensitivity by building sensors that probed the thermal signatures of chemical vapors.

They started with standard micromechanical sensors—devices with microscopic cantilevers beams supported at one end. They modified the cantilevers so that they could be electronically heated by passing a current through them. Next they allowed air to flow over the sensors. If explosive vapors were present in the air, they could be detected when molecules in the vapor clung to the cantilevers.

Then by heating the cantilevers in a fraction of a second, they could discriminate between explosives and non-explosives. All the explosives they tested responded with unique and reproducible thermal response patterns within a split second of heating. In their paper, Thundat and his colleagues demonstrate that they could detect very small amounts of adsorbed explosives—with a limit of 600 picograms (a picogram is a trillionth of a gram). They are now improving the sensitivity and making a prototype device, which they expect to be ready for field testing later this year.

Here’s the paper, behind a paywall.

Posted on March 23, 2009 at 6:55 AM • View Comments

Billboards that Watch you Back

Creepy:

Small cameras can now be embedded in the screen or hidden around it, tracking who looks at the screen and for how long. The makers of the tracking systems say the software can determine the viewer’s gender, approximate age range and, in some cases, ethnicity—and can change the ads accordingly.

That could mean razor ads for men, cosmetics ads for women and video-game ads for teens.

And even if the ads don’t shift based on which people are watching, the technology’s ability to determine the viewers’ demographics is golden for advertisers who want to know how effectively they’re reaching their target audience.

While the technology remains in limited use for now, advertising industry analysts say it is finally beginning to live up to its promise. The manufacturers say their systems can accurately determine gender 85 to 90 percent of the time, while accuracy for the other measures continues to be refined.

These are ads at eye level: on the streets, in malls, in train stations.

Posted on February 11, 2009 at 2:53 PM • View Comments

Clever Counterterrorism Tactic

Used against the IRA:

One of the most interesting operations was the laundry mat [sic]. Having lost many troops and civilians to bombings, the Brits decided they needed to determine who was making the bombs and where they were being manufactured. One bright fellow recommended they operate a laundry and when asked “what the hell he was talking about,” he explained the plan and it was incorporated—to much success.

The plan was simple: Build a laundry and staff it with locals and a few of their own. The laundry would then send out “color coded” special discount tickets, to the effect of “get two loads for the price of one,” etc. The color coding was matched to specific streets and thus when someone brought in their laundry, it was easy to determine the general location from which a city map was coded.

While the laundry was indeed being washed, pressed and dry cleaned, it had one additional cycle—every garment, sheet, glove, pair of pants, was first sent through an analyzer, located in the basement, that checked for bomb-making residue. The analyzer was disguised as just another piece of the laundry equipment; good OPSEC [operational security]. Within a few weeks, multiple positives had shown up, indicating the ingredients of bomb residue, and intelligence had determined which areas of the city were involved. To narrow their target list, [the laundry] simply sent out more specific coupons [numbered] to all houses in the area, and before long they had good addresses. After confirming addresses, authorities with the SAS teams swooped down on the multiple homes and arrested multiple personnel and confiscated numerous assembled bombs, weapons and ingredients. During the entire operation, no one was injured or killed.

Posted on October 13, 2008 at 1:22 PM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.