Scaling up MIMO: Opportunities and Challenges with Very Large Arrays

This paper surveys recent advances in the area of very large MIMO systems. With very large MIMO, we think of systems that use antenna arrays with an order of magnitude more elements than in systems being built today, say a hundred antennas or more. Very large MIMO entails an unprecedented number of antennas simultaneously serving a much smaller number of terminals. The disparity in number emerges as a desirable operating condition and a practical one as well. The number of terminals that can be simultaneously served is limited, not by the number of antennas, but rather by our inability to acquire channel-state information for an unlimited number of terminals. Larger numbers of terminals can always be accommodated by combining very large MIMO technology with conventional time- and frequency-division multiplexing via OFDM. Very large MIMO arrays is a new research field both in communication theory, propagation, and electronics and represents a paradigm shift in the way of thinking both with regards to theory, systems and implementation. The ultimate vision of very large MIMO systems is that the antenna array would consist of small active antenna units, plugged into an (optical) fieldbus.Comment: Accepted for publication in the IEEE Signal Processing Magazine, October 201

A proposal for a scalable universal bosonic simulator using individually trapped ions

We describe a possible architecture to implement a universal bosonic simulator (UBS) using trapped ions. Single ions are confined in individual traps, and their motional states represent the bosonic modes. Single-mode linear operators, nonlinear phase-shifts, and linear beam splitters can be realized by precisely controlling the trapping potentials. All the processes in a bosonic simulation, except the initialization and the readout, can be conducted beyond the Lamb-Dicke regime. Aspects of our proposal can also be applied to split adiabatically a pair of ions in a single trap

System and technique for retrieving depth information about a surface by projecting a composite image of modulated light patterns

A technique, associated system and program code, for retrieving depth information about at least one surface of an object. Core features include: projecting a composite image comprising a plurality of modulated structured light patterns, at the object; capturing an image reflected from the surface; and recovering pattern information from the reflected image, for each of the modulated structured light patterns. Pattern information is preferably recovered for each modulated structured light pattern used to create the composite, by performing a demodulation of the reflected image. Reconstruction of the surface can be accomplished by using depth information from the recovered patterns to produce a depth map/mapping thereof. Each signal waveform used for the modulation of a respective structured light pattern, is distinct from each of the other signal waveforms used for the modulation of other structured light patterns of a composite image; these signal waveforms may be selected from suitable types in any combination of distinct signal waveforms, provided the waveforms used are uncorrelated with respect to each other. The depth map/mapping to be utilized in a host of applications, for example: displaying a 3-D view of the object; virtual reality user-interaction interface with a computerized device; face--or other animal feature or inanimate object--recognition and comparison techniques for security or identification purposes; and 3-D video teleconferencing/telecollaboration

System and technique for retrieving depth information about a surface by projecting a composite image of modulated light patterns

A technique, associated system and program code, for retrieving depth information about at least one surface of an object, such as an anatomical feature. Core features include: projecting a composite image comprising a plurality of modulated structured light patterns, at the anatomical feature; capturing an image reflected from the surface; and recovering pattern information from the reflected image, for each of the modulated structured light patterns. Pattern information is preferably recovered for each modulated structured light pattern used to create the composite, by performing a demodulation of the reflected image. Reconstruction of the surface can be accomplished by using depth information from the recovered patterns to produce a depth map/mapping thereof. Each signal waveform used for the modulation of a respective structured light pattern, is distinct from each of the other signal waveforms used for the modulation of other structured light patterns of a composite image; these signal waveforms may be selected from suitable types in any combination of distinct signal waveforms, provided the waveforms used are uncorrelated with respect to each other. The depth map/mapping to be utilized in a host of applications, for example: displaying a 3-D view of the object; virtual reality user-interaction interface with a computerized device; face--or other animal feature or inanimate object--recognition and comparison techniques for security or identification purposes; and 3-D video teleconferencing/telecollaboration

System and Method for 3D Imaging using Structured Light Illumination

A biometrics system captures and processes a handprint image using a structured light illumination to create a 2D representation equivalent of a rolled inked handprint. A processing unit calculates 3D coordinates of the hand from the plurality of images and maps the 3D coordinates to a 2D flat surface to create a 2D representation equivalent of a rolled inked handprint

System and Method for 3D Imaging using Structured Light Illumination

A biometrics system captures and processes a handprint image using a structured light illumination to create a 2D representation equivalent of a rolled inked handprint. The biometrics system includes an enclosure with a scan volume for placement of the hand. A reference plane with a backdrop pattern forms one side of the scan volume. The backdrop pattern is preferably a random noise pattern and the coordinates of the backdrop pattern are predetermined at system provisioning. The biometrics system further includes at least one projection unit for projecting a structured light pattern onto a hand positioned in the scan volume on or in front of the backdrop pattern and at least two cameras for capturing a plurality of images of the hand, wherein each of the plurality of images includes at least a portion of the hand and the backdrop pattern. A processing unit calculates 3D coordinates of the hand from the plurality of images using the predetermined coordinates of the backdrop pattern to align the plurality of images and mapping the 3D coordinates to a 2D flat surface to create a 2D representation equivalent of a rolled inked handprint. The processing unit can also adjust calibration parameters for each hand scan from calculating coordinates of the portion of backdrop pattern in the at least one image and comparing with the predetermined coordinates of the backdrop pattern

Lock and Hold Structured Light Illumination

A method, system, and associated program code, for 3-dimensional image acquisition, using structured light illumination, of a surface-of-interest under observation by at least one camera. One aspect includes: illuminating the surface-of-interest, while static/at rest, with structured light to obtain initial depth map data therefor; while projecting a hold pattern comprised of a plurality of snake-stripes at the static surface-of-interest, assigning an identity to and an initial lock position of each of the snake-stripes of the hold pattern; and while projecting the hold pattern, tracking, from frame-to-frame each of the snake-stripes. Another aspect includes: projecting a hold pattern comprised of a plurality of snake-stripes; as the surface-of-interest moves into a region under observation by at least one camera that also comprises the projected hold pattern, assigning an identity to and an initial lock position of each snake-stripe as it sequentially illuminates the surface-of-interest; and while projecting the hold pattern, tracking, from frame-to-frame, each snake-stripe while it passes through the region. Yet another aspect includes: projecting, in sequence at the surface-of-interest positioned within a region under observation by at least one camera, a plurality of snake-stripes of a hold pattern by opening/moving a shutter cover; as each of the snake-stripes sequentially illuminates the surface-of-interest, assigning an identity to and an initial lock position of that snake-stripe; and while projecting the hold pattern, tracking, from frame-to-frame, each of the snake-stripes once it has illuminated the surface-of-interest and entered the region