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Researchers Extract Audio from Visual Information

Researchers at MIT, Microsoft, and Adobe have developed an algorithm that can reconstruct an audio signal by analyzing minute vibrations of objects depicted in video. In one set of experiments, the team was able to recover intelligible speech from the vibrations of a potato-chip bag photographed from 15 feet away through soundproof glass."When sound hits an object, it causes the object to vibrate,” says Abe Davis, a graduate student in electrical engineering and computer science at MIT and first author on the new paper. “The motion of this vibration creates a very subtle visual signal that’s usually invisible to the naked eye. People didn’t realize that this information was there.”Reconstructing audio from video requires that the frequency of the video samples — the number of frames of video captured per second — be higher than the frequency of the audio signal. In some of their experiments, the researchers used a high-speed camera that captured 2,000 to 6,000 frames per second. The researchers’ technique has obvious applications in law enforcement and forensics, but Davis is more enthusiastic about the possibility of what he describes as a “new kind of imaging.”“We’re recovering sounds from objects,” he says. “That gives us a lot of information about the sound that’s going on around the object, but it also gives us a lot of information about the object itself, because different objects are going to respond to sound in different ways.” In ongoing work, the researchers have begun trying to determine material and structural properties of objects from their visible response to short bursts of sound. Source Also: Learn about Enhanced Auditory Alert Systems.

Posted in: Electronics & Computers, Cameras, Video, Imaging, Software, News

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NASA Begins Engine Test of Space Launch System Rocket

Engineers are preparing to test parts of NASA's Space Launch System (SLS) rocket that will send humans to space. They installed an RS-25 engine on the A-1 Test Stand at Stennis Space Center. The Stennis team will perform developmental and flight certification testing of the RS-25 engine, a modified version of the space shuttle main engine. The SLS's core stage will be powered by a configuration of four RS-25 engines.

Posted in: Motion Control, Motors & Drives, Power Transmission, Test & Measurement, Aerospace, Aviation, News

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Airbags Take the Weight in Load Tests of Aircraft

NASA Armstrong Flight Research Center’s Flight Loads Laboratory completed structural evaluations on a modified Gulfstream G-III aircraft that will serve as a test bed for the Adaptive Compliant Trailing Edge (ACTE) project. The loads tests assisted engineers in predicting the levels of structural stress the airplane will likely experience during ACTE research flights. And for the first time, some unusual hardware aided the process: the aircraft was supported by three large inflatable airbags during the tests.

Posted in: Mechanical Components, Test & Measurement, Aerospace, Aviation, News

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Students Learn On-the-Fly Engineering in Solar Car Competition

Nine teams of solar powered model cars competed during the inaugural Junior Solar Sprint (JSS) competition held at the STEM Education and Outreach Center at Aberdeen Proving Ground, MD. The JSS is a nationwide competition funded by the Army Educational Outreach Program, which challenges teams of students from elementary and middle school to design, construct, and race small model cars powered entirely by solar energy.

Posted in: Motion Control, Motors & Drives, Solar Power, Renewable Energy, Energy, News, Automotive

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Cassini Spacecraft Reveals Geysers and More on Saturn Moon

Scientists using mission data from NASA’s Cassini spacecraft have identified 101 distinct geysers erupting on Saturn’s icy moon Enceladus. Their analysis suggests it is possible for liquid water to reach from the moon’s underground sea all the way to its surface.

Posted in: Imaging, Aerospace, News

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Acoustic Bottle Bends Paths of Sound Waves

Researchers with the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) have developed a technique for generating acoustic bottles in open air that can bend the paths of sound waves along prescribed convex trajectories.The acoustic “bottle” features a three-dimensional curved shell, in which a wall of high acoustic pressure surrounds a null pressure region in the middle. Sound waves forming the bottle are concentrated into a beam that travels through the high pressure wall of its curved shell. The sound waves are generated by an array of loud speakers, 1.5 centimeters in diameter and spaces 2.5 centimeters apart, operating at a frequency of 10 kilo Hertz (kHz) and can be launched along a designated trajectory by precisely adjusting the phase profile of the speaker array.Because the high pressure wall of the acoustic bottle exerts a pulling force, there are no sound waves passing through the null pressure interior of the bottle and the bottle can be used for acoustic trapping."Our acoustic bottle beams open new avenues to applications in which there is a need to access hard-to-reach objects hidden behind obstacles, such as acoustic imaging and therapeutic ultrasound through inhomogeneous media,” said team member Tongcang Li. “We can also use an acoustic bottle as a cloaking device, re-routing sound waves around an object and then recovering them in their original form, making the object invisible to sonar detection.”Acoustic bottle beams might also serve another application: acoustic levitation, in which sound waves are used to lift and manipulate millimeter-sized objects, including particles, microorganisms and droplets of water.SourceAlso: Learn about a High-Temperature Surface-Acoustic-Wave Transducer.

Posted in: Imaging, News

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'Active' Surfaces Control How Particles Move

Researchers at MIT and in Saudi Arabia have developed a new way of making surfaces that can actively control how fluids or particles move across them. The work might enable new kinds of biomedical or microfluidic devices, or solar panels that could automatically clean themselves of dust and grit.The system makes use of a microtextured surface, with bumps or ridges just a few micrometers across, that is then impregnated with a fluid that can be manipulated — for example, an oil infused with tiny magnetic particles, or ferrofluid, which can be pushed and pulled by applying a magnetic field to the surface. When droplets of water or tiny particles are placed on the surface, a thin coating of the fluid covers them, forming a magnetic cloak.The thin magnetized cloak can then actually pull the droplet or particle along as the layer itself is drawn magnetically across the surface. Tiny ferromagnetic particles, approximately 10 nanometers in diameter, in the ferrofluid could allow precision control when it’s needed — such as in a microfluidic device used to test biological or chemical samples by mixing them with a variety of reagents. Unlike the fixed channels of conventional microfluidics, such surfaces could have “virtual” channels that could be reconfigured at will.The new approach could be useful for a range of applications: For example, solar panels and the mirrors used in solar-concentrating systems can quickly lose a significant percentage of their efficiency when dust, moisture, or other materials accumulate on their surfaces. But if coated with such an active surface material, a brief magnetic pulse could be used to sweep the material away.Source Also: Read more Materials tech briefs.

Posted in: Motion Control, Fluid Handling, Medical, Drug Delivery & Fluid Handling, Solar Power, Renewable Energy, Energy, News

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