Found this article interesting hope others will as well.
http://www.wired.com/news/technology/0,72632-0.html
Hope this is not a duplicate.
NukemJim
http://www.wired.com/news/technology/0,72632-0.html
In the Matrix, characters could see bullets in slow motion as they sped toward them. Now, the U.S. military can too.
An Air Force contractor has developed the first high-speed camera that can follow speeding bullets midflight. It may lead to "active armor" that intercepts speeding rounds out of the air, or personal-protection devices that deflect incoming bullets with rapidly inflating Kevlar air bags.
Developed for the Air Force's Munitions Directorate by Nova Sensors of Solvang, California, the Variable Acuity Superpixel Technology system, or VAST, can also track anything slower than a bullet -- which is pretty much everything -- and is likely to find many other applications, from traffic management to robot vision.
"This is truly breakthrough technology in terms of new capabilities for infrared focal plane arrays," says Mark Massie, president of Nova Sensors.
Nova Sensors' system includes software that mimics the fovea in human and animal eyes. The fovea is the dense region of light receptors at the center of the eye used for detailed vision: reading, driving a car or examining objects closely.
The electronic version consists of a sensor with a 320-by-256 array of pixels and software that concentrates on "areas of interest," like a virtual fovea would do. The areas of interest are at maximum resolution, while everything else in VAST's field of view is seen at a lower resolution. This two-tier system allows VAST to devote maximum processing power to certain areas, while monitoring a much wider field of view.
Speed is the key. Because the sensor's frame rate is limited by how fast data can be processed, the fovealike software can have a very high frame rate -- faster than a speeding bullet.
The sensor can include several areas that act as virtual foveas. These virtual foveas can move around the sensor as an object is tracked. In the video below, the system tracks a flying .22-caliber bullet at about 1,000 feet per second. See this gallery for a more detailed explanation of how the system works.
High-speed sensors traditionally require subjects to be lit by a strobe or flash photography -- otherwise they're too dark to detect. In contrast, the VAST system detects objects by the heat they emit instead of by the light. Because of this ability, the VAST sensor "sees" bullets in the midinfrared.
Bullets shot at supersonic speeds heat up and glow like light bulbs in infrared -- making them relatively easy for the sensor to pick out.
"The tracking algorithm that our camera was using was simply placing the fovea on the brightest (hottest) object in each frame," says Massie.
In early tests, the VAST system followed .22- and .30-caliber bullets.
Robert Fisher, a professor at the University of Edinburgh's School of Informatics in the United Kingdom, says the idea is not new, but getting it to work is.
"It looks like a perfectly feasible approach," he says. "There have been laboratory developments of a variety of these foveal sensors over the past 10 years, but the biggest issue has been money. Obviously the military has a different kind of market and they have been able to get funding."
The system may have many applications -- military and civilian -- from pinpointing snipers to guiding smart missiles.
Instead of thick steel plates, military vehicles could be fitted with foveal sensors and active armor that intercepts incoming projectiles.
So-called active-protection systems, already being developed by the United States, Russia and Israel, disrupt incoming rounds with a blast of focused shrapnel. But these systems use radar to detect incoming rounds, and only detect projectiles about a hundred meters away. Nova Sensors claims the foveal camera has far better performance.
".22-caliber bullets may be visible for many hundreds of meters," says Massie. "Larger-caliber bullets may be visible a kilometer away."
Newer active-protection systems based on VAST sensors should be able to stop the full spectrum of threats, including large-caliber, high-velocity tank rounds, Massie says.
Similar systems could also provide personal protection. One company working with the Army is looking at a device that inflates a Kevlar air bag in the path of a bullet. This could be installed in doorways, windows or furniture.
In addition to seeing bullets, the VAST sensor can also track their trajectories, which can be traced forward to see if the bullet is on target or will miss, or traced back to the precise location of a hidden sniper. In the video below, the system tracks bullets and flying shrapnel at approximately 250 frames per second.
The Air Force is also testing the foveating sensor for guiding unmanned aircraft: The ability to pick out small areas of interest like moving vehicles without losing the big picture is a major asset. In addition, the foveal window is highly stabilized, canceling out any movement or vibration, which makes it ideal for moving platforms like unmanned vehicles or guided missiles.
The system can also be used for general night vision; it can follow bats five miles away in darkness.
Nova Sensors is now working on a larger array and newer, more reliable tracking algorithms.
Massie believes that the development will lead to ultra-fast, ultra-compact cameras.
"Mimicking tracking functions of the human visual system will permit future infrared cameras to provide the most salient high-speed imagery in cameras that are very small in size, may be operated on battery power, and produce very low-output bandwidth data," he says.
Hope this is not a duplicate.
NukemJim
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