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Feature Story
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Friday, 03 May 2013 |
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 Inspired by the complex fly eye, an interdisciplinary team led by researchers at the University of Illinois at Urbana-Champaign and Northwestern University has developed a hemispherical digital camera with nearly 200 tiny lenses, delivering exceptionally wide-angle field of view and sharp images.
Humans capture pictures using the two lenses of our relatively flat eyes, while a top-of-the-line SLR camera has just one flat lens. The new camera -- a rounded half bubble, similar to a bulging fly eye -- has 180 microlenses mounted on it, allowing it to take pictures across nearly 180 degrees. Only a camera shaped like a bug's eye can do this.
With this wide-angle field of view, the new technology could be used in future surveillance devices or for imaging in endoscopic procedures. The researchers say it would be simple enough to combine two of the hemispheres they've demonstrated to get a 360-degree view.
Details of the bio-inspired camera, which required experts in optics, electronics, fabrication, and modeling and design theory, is published in the May 2 issue of the journal Nature.
"What we have, in a sense, is many small eyes on one big eye," said Northwestern's Yonggang Huang, a senior author of the paper. "Each small eye, composed of a microlens and a microscale photodetector, is a separate imaging system, but when they are all taken together, the camera can take a clear picture, with just one snap, of nearly 180 degrees.
"The interface of different fields generates interesting new devices that never existed before," he said. Huang is the Joseph Cummings Professor of Civil and Environmental Engineering and Mechanical Engineering at the McCormick School of Engineering and Applied Science.
Huang's lab was responsible for the modeling and design theory for the project, which took the whole team three years to complete.
The digital camera is just the latest innovation in a long and fruitful collaboration between two engineers -- Huang and John A. Rogers at the University of Illinois at Urbana-Champaign -- that has developed stretchable electronics and various devices using the technology, including an earlier digital camera, advanced surgical tools and health/wellness monitors.
Their electronics, which can bend, twist and stretch without breaking, were well suited to the challenge of developing a hemispherical camera.
"Full 180-degree fields of view with zero aberrations can only be accomplished with image sensors that adopt hemispherical layouts -- much different than the planar CCD chips found in commercial cameras," said Rogers, a Swanlund Chair Professor, of the new camera.
"When implemented with large arrays of microlenses, each of which couples to an individual photodiode, this type of hemispherical design provides unmatched field of view and other powerful capabilities in imaging," he said. "Nature has developed and refined these concepts over the course of billions of years of evolution."
Eyes in arthropods use compound designs, in which arrays of smaller eyes act together to provide image perception. Each small eye, known as an ommatidium, consists of a corneal lens, a crystalline cone and a light-sensitive organ at the base. The entire system is configured to provide exceptional properties in imaging, many of which lie beyond the reach of existing man-made cameras.
The 180 microlenses of Roger and Huang's camera is comparable to the eye of fire ants and bark beetles, but less than the fly eye, which has thousands of small eyes.
"Existing camera imaging technology is flat, and we made a system that is curvilinear," Huang said. "Making a stretchable array of photodetectors was easy -- that's what we do. The difficult part was making a hemispherical lens. We needed to make sure the lens experienced as little strain as possible when stretched."
The researchers developed new ideas in materials and fabrication strategies allowing construction of artificial ommatidia in large, interconnected arrays in hemispherical layouts. Building such systems represents a daunting task, as all established camera technologies rely on bulk glass lenses and detectors constructed on the planar surfaces of silicon wafers which cannot be bent or flexed, much less formed into a hemispherical shape.
"A critical feature of our fly eye cameras is they incorporate integrated microlenses, photodetectors and electronics on hemispherically curved surfaces," said Jianliang Xiao, an assistant professor of mechanical engineering at University of Colorado Boulder and coauthor of the study. "To realize this outcome, we used soft, rubbery optics bonded to detectors/electronics in mesh layouts that can be stretched and deformed, reversibly and without damage."
Xiao is a former doctoral student of Huang's at Northwestern who then went on to work as a postdoctoral researcher in Rogers' lab at Illinois.
The fabrication starts with electronics, detectors and lens arrays formed on flat surfaces using advanced techniques adapted from the semiconductor industry, Xiao said. The lens sheet -- made from a polymer material similar to a contact lens -- and the electronics/detectors are then aligned and bonded together. Pneumatic pressure deforms the resulting system into the desired hemispherical shape, in a process much like blowing up a balloon, but with precision engineering control.
The individual electronic detectors and microlenses are coupled together to avoid any relative motion during this deformation process. Here, the spaces between these artificial ommatidia can stretch to allow transformation in geometry from planar to hemispherical. The electrical interconnections are thin and narrow, in filamentary serpentine shapes; they deform as tiny springs during the stretching process.
According to the researchers, each microlens produces a small image of an object with a form dictated by the parameters of the lens and the viewing angle. An individual detector responds only if a portion of the image formed by the associated microlens overlaps the active area. The detectors stimulated in this way produce a sampled image of the object that can then be reconstructed using models of the optics.
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Tuesday, 23 April 2013 |
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 Four students from a college in Liège (HEPL), Belgium, have developed prototype glasses that enable firefighters to easily move around without losing their orientation in case of fire.
The inventors are in their third year of college at HEPL and have participated in a contest organised by Microsoft that highlights student's technological inventions, called "Imagine Cup". Their project "Hateya" won the local competition.
They have developed this system in order to help firefighters to find their way and locate themselves in a smoky environment. The built-in sensors in the firefighter's jacket provide the necessary information to the firefighter via augmented reality data displayed in the glasses they wear. The system is similar to some GPS systems that can locate and map movements and find the way.
More information at: www.hateya.be
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Feature Story
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Tuesday, 26 February 2013 |
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 Researchers from The National Institute of Informatics (NII) and Kogakuin University in Japan have developed, under leading of associate professor Isao Echizen, new technology that provides a way to protect the privacy of photographed subjects. In recent years facial recognition has been integrated into security cameras and databases and Facebook, even used to covertly monitor consumers and track shopping habits.
This new technological development can disable facial recognition of photographed subjects only when photos are taken. It achieves this by the photographed person wearing a privacy visor that incorporates a near-infrared light source that affects only the camera and not people's vision. These visors are able to protect photographed subjects from the invasion of privacy resulting from the facial recognition functionality and the widespread use of augmented reality applications. The glasses, currently in prototype form, are hardly what you would term stylish. They are essentially a pair of clunky-looking lab goggles. Attached to them are small circular lights that, when turned on, are visible only to cameras. They are connected to a wire and a battery that you have to carry in your pocket.
For more information download their document at: http://www.nii.ac.jp/userimg/press_20121212e.pdf
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Feature Story
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Tuesday, 22 January 2013 |
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 Google has filed a patent for mounting twin lasers on the sides of a pair of glasses to display a keyboard on a user's body parts and use a camera to track a hand's gestures for control.
"A pattern for a virtual input device can be projected onto a 'display hand' of a user, and the camera may be able to detect when the user uses an opposite hand to select items of the virtual input device," the filing reads. "In another example, the camera may detect when the display hand is moving and interpret display hand movements as inputs to the virtual input device, and/or realign the projection onto the moving display hand."
The patent filing shows the lasers projecting a numeric keyboard onto the palm of the hand, or highlighting function buttons on the forearm. By looking at the relevant body-part, someone wearing the specs – which look very like the Google Glass prototypes – could find some way to input data beyond speech recognition and use gesture controls on the eyewear's lenses. Laser projection of keyboards is a decade-old idea, but this might be the way to solve a fundamental problem with Google's hardware: reliable input. As some have pointed out, Glass has significant problems in terms of user control.
Google management is strongly behind making the Glass project a success, and Sergey Brin is seldom seen at public events without a set on. What isn't covered in the patent filing is the issue of screen burn. As anyone with a plasma TV will tell you, a station's logo can permanently mark a section of the screen, but the lasers involved are certainly low-power enough not to cause problems. The patent has yet to be approved, but if Google can come up with a working prototype the results could be very interesting indeed.
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Feature Story
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Thursday, 29 November 2012 |
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 They say that the eyes are the windows to the soul. However, to get a real idea of what a person is up to, according to University of California Santa Barbara researchers Miguel Eckstein and Matt Peterson, the best place to check is right below the eyes. Their findings are published in the Proceedings of the National Academy of Science.
"It's pretty fast, it's effortless –– we're not really aware of what we're doing," said Miguel Eckstein, professor of psychology in the Department of Psychological & Brain Sciences. Using an eye tracker and more than 100 photos of faces and participants, Eckstein and graduate research assistant Peterson followed the gaze of the experiment's participants to determine where they look in the first crucial moment of identifying a person's identity, gender, and emotional state.
"For the majority of people, the first place we look at is somewhere in the middle, just below the eyes," Eckstein said. One possible reason could be that we are trained from youth to look there, because it's polite in some cultures. Or, because it allows us to figure out where the person's attention is focused.
However, Peterson and Eckstein hypothesize that, despite the ever-so-brief –– 250 millisecond –– glance, the relatively featureless point of focus, and the fact that we're usually unaware that we're doing it, the brain is actually using sophisticated computations to plan an eye movement that ensures the highest accuracy in tasks that are evolutionarily important in determining flight, fight, or love at first sight.
"When you look at a scene, or at a person's face, you're not just using information right in front of you," said Peterson. The place where one's glance is aimed is the place that corresponds to the highest resolution in the eye –– the fovea, a slight depression in the retina at the back of the eye –– while regions surrounding the foveal area –– the periphery –– allow access to less spatial detail.
However, according to Peterson, at a conversational distance, faces tend to span a larger area of the visual field. There is information to be gleaned, not just from the face's eyes, but also from features like the nose or the mouth. But when participants were directed to try to determine the identity, gender, and emotion of people in the photos by looking elsewhere –– the forehead, the mouth, for instance –– they did not perform as well as they would have by looking close to the eyes.
Using a sophisticated algorithm, which mimics the varying spatial detail of human processing across the visual field and integrates all information to make decisions, allowed Peterson and Eckstein to predict what would be the best place within the faces to look for each of these perceptual tasks. They found that these predicted places varied moderately across tasks, and closely corresponded to where humans actually do look.
At least for the three important tasks investigated –– identity, emotion, and gender –– below the eyes is the optimal place to look, say the scientists, because it allows one to read information from as many features of the face as possible.
"What the visual system is adept at doing is taking all those pieces of information from your face and combining them in a statistical manner to make a judgment about whatever task you're doing," said Eckstein. The area around the eyes contains minute bits of important information, which require the high resolution processing close to the fovea, whereas features like the mouth are larger and can be read without a direct gaze.
The study shows that the ability to learn optimal rapid eye movement for evolutionarily important perceptual tasks is inherent in humans; however, say the scientists, it is not necessarily consistent behavior for everybody. Eckstein's lab is currently involved in studying a small subset of people who do not look just below the eyes to identify a person. Other researchers have shown that East Asians, for instance, tend look lower on the face when identifying a person's face.
The research by Peterson and Eckstein has resulted in sophisticated new algorithms to model optimal gaze patterns when looking at faces. The algorithms could potentially be used to provide insight into conditions like schizophrenia and autism, which are associated with uncommon gaze patterns, or prosopagnosia –– an inability to recognize someone by his or her face.
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Feature Story
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Thursday, 18 October 2012 |
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 A new type of laser eye protection (LEP) for pilots is being tested by the Ministry of Defence in UK. The Defence Science and Technology Laboratory (Dstl) has been working with Defence Equipment and Support (DE&S) to evaluate and assess the specially designed spectacles. The LEPs can filter out different wavelengths of light from the spectrum, including those used in various laser weapons and laser pens, which are becoming increasingly available from the internet.
Dr Craig Williamson, Principal Scientist at Dstl, explained the rationale behind the project work: "There are an increasing number of incidents of inexpensive lasers being used to distract pilots, so we have been researching advanced technologies to mitigate this hazardous and potentially lethal distraction," he said. Unlike conventional LEP, which tends to filter out and block just one wavelength from the colour spectrum, the prototype spectacles, made by Glasgow-based company Thin Film Solutions, can filter out a range of different laser wavelengths, allowing greater operational benefits and flexibility for pilots. This is achieved by a composite structure comprising a polycarbonate layer, made with a special absorbing optical dye, bonded to a thin glass lens with a special coating to reflect certain wavelengths.
The project work on the LEP is a good example of how funding from DE&S's equipment programme can be used to evaluate technology and assess it for potential benefits and uses.
Pete Douglass of DE&S explained: "With funding from the equipment programme we were able to ask Dstl to evaluate this new LEP against older, more conventional filters in order to understand the development needs before they would be ready for service," he said. "In the case of the LEP, the research highlighted some clear strengths, whilst also showing some weaknesses of the technology which we are now addressing with future research."
The work has also benefited from an established partnership between Dstl and the United States Air Force, with testing having taken place in May of this year.
Dr Williamson said: "The bilateral work at the United States Air Force Tri-Service Research Laboratory in San Antonio proved to be invaluable. "The results from this human performance testing on spatial detection and colour perception have set the benchmark for future work, and we're hoping that further bilateral funding will be available to research the next generation of eye protection in the coming years."
Further testing is to be conducted later this year, including optical performance and environmental testing by Dstl, and laser dazzle and performance testing at QinetiQ.
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