7 In 10 Indonesian Children Exposed To Dengue

In a study conducted on more than 3,000 Indonesian children from ages one to 18, nearly 70 percent tested positive for dengue antibodies, an indication that they have been infected before.

Ultra-thin camera design doesn’t need a lens

Traditional cameras—even those on the thinnest of cell phones—cannot be truly flat due to their optics: lenses that require a certain shape and size in order to function.

A new camera design replaces the lenses with an ultra-thin optical phased array (OPA) that does computationally what lenses do using large pieces of glass: it manipulates incoming light to capture an image.

OPA on penny for scale
OPA on penny for scale. (Credit: Caltech)
lensless camera prototype
(Credit: Caltech)

Lenses have a curve that bends the path of incoming light and focuses it onto a piece of film or, in the case of digital cameras, an image sensor. The OPA has a large array of light receivers, each of which can individually add a tightly controlled time delay (or phase shift) to the light it receives, enabling the camera to selectively look in different directions and focus on different things.

“Here, like most other things in life, timing is everything. With our new system, you can selectively look in a desired direction and at a very small part of the picture in front of you at any given time, by controlling the timing with femto-second—quadrillionth of a second—precision,” says Ali Hajimiri, professor of electrical engineering and medical engineering at California Institute of Technology and principal investigator of a paper in OSA Technical Digest.

“We’ve created a single thin layer of integrated silicon photonics that emulates the lens and sensor of a digital camera, reducing the thickness and cost of digital cameras. It can mimic a regular lens, but can switch from a fish-eye to a telephoto lens instantaneously—with just a simple adjustment in the way the array receives light.”

Camera prototype is thinner than a dime

Phased arrays, which are used in wireless communication and radar, are collections of individual transmitters, all sending out the same signal as waves. These waves interfere with each other constructively and destructively, amplifying the signal in one direction while canceling it out elsewhere. So, an array can create a tightly focused beam of signal, which can be steered in different directions by staggering the timing of transmissions made at various points across the array.

A similar principle is used in reverse in an optical phased array receiver, which is the basis for the new camera. Light waves that are received by each element across the array cancel each other from all directions, except for one. In that direction, the waves amplify each other to create a focused “gaze” that can be electronically controlled.

“What the camera does is similar to looking through a thin straw and scanning it across the field of view. We can form an image at an incredibly fast speed by manipulating the light instead of moving a mechanical object,” says graduate student Reza Fatemi, the paper’s lead author.

Last year, Hajimiri’s team rolled out a one-dimensional version of the camera that was capable of detecting images in a line, such that it acted like a lensless barcode reader but with no mechanically moving parts.

New camera uses just 1 photon per pixel

This year’s advance was to build the first two-dimensional array capable of creating a full image. This first 2D lensless camera has an array composed of just 64 light receivers in an 8 by 8 grid. The resulting image has low resolution—but the system represents a proof of concept for a fundamental rethinking of camera technology, researchers say.

“The applications are endless,” says graduate student and coauthor Behrooz Abiri. “Even in today’s smartphones, the camera is the component that limits how thin your phone can get. Once scaled up, this technology can make lenses and thick cameras obsolete. It may even have implications for astronomy by enabling ultra-light, ultra-thin enormous flat telescopes on the ground or in space.”

“The ability to control all the optical properties of a camera electronically using a paper-thin layer of low-cost silicon photonics without any mechanical movement, lenses, or mirrors, opens a new world of imagers that could look like wallpaper, blinds, or even wearable fabric,” says Hajimiri.

The team will next work on scaling up the camera by designing chips that enable much larger receivers with higher resolution and sensitivity.

Source: Caltech

The post Ultra-thin camera design doesn’t need a lens appeared first on Futurity.

The origin of the tabby coat and other cat mysteries revealed

FELINE HISTORY: A new study on how cats conquered the world - and our hearts - has answered long-standing questions.

Criminals are using drones to airdrop drugs and porn into prison

Amazon is experimenting with drone delivery in hopes to ship your impulse buys through the air, but a much seedier group seems to have already mastered the craft– much to the chagrin of law enforcement groups across the United States.

According to a report published this weekend by USA Today, drones have been used on at least a dozen occasions to smuggle contraband such as drugs, phones, and porn into multiple federal and state prisons since 2012, including incidents in the states of California, Maryland, and Ohio.

While several of the incidents were known to media outlets including The Washington Post and The Verge, others were uncovered in documents obtained by USA Today from the Department of Justice through a Freedom of Information Act request, the newspaper explained in its report.

In March 2015, a drone was used to deliver two cell phones to an inmate at a high-security federal prison in Victorville, California, and the contraband reportedly when unnoticed for five months. In 2016 three individuals, including a recently-released former inmate, were charged with using UAVs to smuggle drugs and porn into Maryland’s Western Correctional Institution.

Similar incidents are also said to have taken place at the United States Penitentiary in Atwater, California; Federal Correctional Institutions in Oakdale, Louisiana and Seagoville, Texas; and a prison in Ohio where a melee broke out after a drone dropped heroin in the exercise yard.

UK prison using a system that could prevent UAV deliveries

The drones being used in these smuggling operations aren’t high-tech devices, according to the Washington Post – they are commercially available UAVs that can be purchased for at stores or online for as little as $50. The problem, experts told USA Today, is that the anti-drone systems at prisons are currently inadequate to prevent such airborne deliveries.

“Civilian drones are becoming more inexpensive, easy to operate and powerful,” Troy Rule, an Arizona State University law professor pushing for stronger drone legislation, explained to the newspaper. “A growing number of criminals seem to be recognizing their potential value as tools for bad deeds.”

“We are trying to keep up with technology just like everyone else. So this is a huge challenge for all of us in corrections,” Stephen T. Moyer, secretary of public safety and correctional services in Maryland, told the Post. Following the incident in his state, Moyer asked for and was told he will receive $1.5 million in funding from the governor to test UAV detection systems.

In May, Les Nicolles Prison in the UK became the first to use a new system designed to prevent drones from flying over its walls, The Telegraph said. The device in question, called Sky Fence, is what is called a disruptor. It creates a 2,000 foot (600 meters) shield around the jail that causes a UAV’s systems to become jammed, blocks its frequency and control protocols, and makes the operator’s screen go black, the newspaper noted.

As Richard Gill, CEO of Sky Fence creator Drone Defence explained, “It disrupts the control network between the flyer and the drone. The drone then activates return to home mode and it will then fly back to the position where it last had a signal with its flyer. Someone described it as the final piece in a prison’s security puzzle. I think it could have a significant worldwide impact.”


Image credit: Ricardo Gomez Angel/Unsplash

The post Criminals are using drones to airdrop drugs and porn into prison appeared first on Redorbit.

Chinese scientists use satellite to smash quantum entanglement record

SPOOKY ACTION: Scientists have used satellite technology for the first time to generate and transmit entangled photons - particles of light - across a record distance of 1,200 kilometres on Earth.
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