Science Daily May 7, 2019 Researchers in Japan have developed a method for identifying the location of point-like scatterers based on fluctuations in the physical properties of the surface. They extracted information on the far-field wave properties of the Green’s function by using the so-called “steepest descent path” and “pseudo-projections” methods. Then, the far-field operator was defined based on the near-field observation and the far-field properties of the Green’s function. They used this far-field operator to obtain the indicator functions that determine the position of the scatterers. They successfully demonstrated the reconstruction of densely packed point-like scatterers using the sensor […]
Category Archives: Imaging technology
Bionics: Electric view in murky waters
Science Daily April 9, 2019 African Elephantnose fish use two different types of electro-receptors for active electrolocation. One only measures the intensity of the signal, the other the waveform of the pulse. Researchers in Germany showed that the fish uses the ratio of the two readings to identify its prey. This creates “electric colors” analogous to visual colors perceived by the human eye, but through electrical signals instead of visible light. They introduced an image cue, called the ‘electric outline’, which provided information resembling a target’s optical contour. The results indicate that bio-inspired electric imaging principles provide promising cues for […]
Listening to quantum radio
Science Daily March 8, 2019 It becomes increasingly difficult to detect long-wavelength single photons because of thermal fluctuations in the background. Researchers in the Netherlands used a superconducting qubit to directly observe the quantization of radio-frequency electromagnetic fields stored in a photonic microresonator. They were then able to manipulate the quantum state of the radio-frequency field, forming one- and two-photon Fock states within the microresonator, and analyze how the system interacts dynamically with its environment. Extending circuit quantum electrodynamics approach could be used for fundamental studies in quantum thermodynamics and find practical application in imaging…read more. TECHNICAL ARTICLE
Autonomous drones can help search and rescue after disasters
Phys.org March 5, 2019 Researchers at the University of Dayton has developed an artificial neural network system that can run in a computer onboard a drone. First the system processes the images to improve their clarity. The system can identify people in various positions from different viewing angles and in varying lighting conditions, compute three-dimensional models of people, detect an object without seeing the whole object. The system has a strategy to focus the search area to the most significant regions in the scene to obtain information about the shape, structure and texture of objects and flags it the location […]
New program picks out targets in a crowd quickly and efficiently
Phys. org February 22, 2019 Previous work on visual search has focused on searching for perfect matches of a target after extensive category-specific training. An international team of researchers (Singapore, USA – University of Minnesota) shows that humans can efficiently and invariantly search for natural objects in complex scenes. They developed a biologically inspired computational model that can locate targets without exhaustive sampling and generalize to novel objects. They trained the model to look for something that had similar features to the example image of a dog. This enabled the model to generalize from a single dog image, to the […]
Toward Ghost Imaging on a Chip
Optics and Photonics February 12, 2019 To overcome the bulky spatial light modulators and other optical components for ghost imaging, researchers in Japan used a phased array of 128 tiny phase shifters packed onto a chip with a 4×4-mm footprint. In the chip setup, input light from a 1550-nm laser, coupled into the array via a lensed fiber, is split into 128 waveguides and piped into the phase-shifting elements of the array. Each individual phase shifter can be electrically controlled, allowing rapid creation of a series of random speckled patterns at refresh rates faster than the few-frame-per-second. The random pattern […]
Shadowy algorithm allows digital camera to see round corners
Physics World January 25, 2019 If the line of sight between a target object and a camera is blocked some of the light from the target can reach the camera via diffuse scattering from surrounding objects. Researchers at Boston University have achieved non-line-of-sight imaging with an ordinary digital camera without the need for measuring arrival times. Their algorithm analyses information that is contained in shadows cast by an obscuring object that is placed between the target object and the relay surface. The technique relies on the fact that shadows are not sharp, but rather have penumbrae at their edges. The […]
New security scanners safely detect threats from people on the move
Phys.org October 8, 2018 The EU-funded SPIDERS project, has developed a ‘passive scanning’ solution which is based on a real time (up to 16 images by second), imaging system, working at millimetre wave frequencies and able to see through clothes and detect hidden objects such as liquids, powders or solids (metal or not). Crucially, the system dubbed ‘MM-Imager’, does not emit any radiation. The technology is based on the measurement of the natural radiation emitted by bodies at microwave frequencies (around 0.1THz). The SPIDERS system works in real time which makes the technology applicable to a wide range of potential […]
Images: Decoding multiple frames from a single, scattered exposure
Science Daily September 27, 2018 The random process of scattering in turbid media produces scattered light that appears uninformative to the human eye, but a wealth of information is contained in the signal. Previous methods to recover the image from the ‘memory effects’ required that the object and/or scatterer be static during the measurement. Researchers at Duke University combined traditional memory effect imaging with coded-aperture-based computational imaging techniques, which enabled them to realize for the first time single-shot video of arbitrary dynamic scenes through opaque media. This has important implications for a wide range of real-world imaging scenarios in security, […]
New Army technology guides soldiers in complete darkness
Phys.org September 26, 2018 Man-made objects emit thermal radiation that is partially polarized while natural objects tend to emit thermal radiation that exhibits very little polarization. Researchers at the Army Research Laboratory and their industry partner are developing a special type of thermal camera that can record imagery that is based solely on the polarization state of the light rather than the intensity. This additional polarimetric information will allow soldiers to see hidden objects that were previously not visible when using conventional thermal cameras. The camera can detect and identify specific human subjects during complete darkness…read more.