141,422 research outputs found

    Rapid mapping of digital integrated circuit logic gates via multi-spectral backside imaging

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    Modern semiconductor integrated circuits are increasingly fabricated at untrusted third party foundries. There now exist myriad security threats of malicious tampering at the hardware level and hence a clear and pressing need for new tools that enable rapid, robust and low-cost validation of circuit layouts. Optical backside imaging offers an attractive platform, but its limited resolution and throughput cannot cope with the nanoscale sizes of modern circuitry and the need to image over a large area. We propose and demonstrate a multi-spectral imaging approach to overcome these obstacles by identifying key circuit elements on the basis of their spectral response. This obviates the need to directly image the nanoscale components that define them, thereby relaxing resolution and spatial sampling requirements by 1 and 2 - 4 orders of magnitude respectively. Our results directly address critical security needs in the integrated circuit supply chain and highlight the potential of spectroscopic techniques to address fundamental resolution obstacles caused by the need to image ever shrinking feature sizes in semiconductor integrated circuits

    Wireless Software Synchronization of Multiple Distributed Cameras

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    We present a method for precisely time-synchronizing the capture of image sequences from a collection of smartphone cameras connected over WiFi. Our method is entirely software-based, has only modest hardware requirements, and achieves an accuracy of less than 250 microseconds on unmodified commodity hardware. It does not use image content and synchronizes cameras prior to capture. The algorithm operates in two stages. In the first stage, we designate one device as the leader and synchronize each client device's clock to it by estimating network delay. Once clocks are synchronized, the second stage initiates continuous image streaming, estimates the relative phase of image timestamps between each client and the leader, and shifts the streams into alignment. We quantitatively validate our results on a multi-camera rig imaging a high-precision LED array and qualitatively demonstrate significant improvements to multi-view stereo depth estimation and stitching of dynamic scenes. We release as open source 'libsoftwaresync', an Android implementation of our system, to inspire new types of collective capture applications.Comment: Main: 9 pages, 10 figures. Supplemental: 3 pages, 5 figure

    3D environment mapping using the Kinect V2 and path planning based on RRT algorithms

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    This paper describes a 3D path planning system that is able to provide a solution trajectory for the automatic control of a robot. The proposed system uses a point cloud obtained from the robot workspace, with a Kinect V2 sensor to identify the interest regions and the obstacles of the environment. Our proposal includes a collision-free path planner based on the Rapidly-exploring Random Trees variant (RRT*), for a safe and optimal navigation of robots in 3D spaces. Results on RGB-D segmentation and recognition, point cloud processing, and comparisons between different RRT* algorithms, are presented.Peer ReviewedPostprint (published version

    Demonstration of fundamental mode only propagation in highly multimode fibre for high power EDFAs

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    The use of short lengths of large core phosphate glass fibre, doped with high concentrations of Er or Er:Yb represents an attractive route to achieving high power erbium doped fibre amplifiers (EDFAs) and lasers (EDFLs). With the aim of investigating the potential of achieving diffraction limited output from such large core fibres, we present experimental results of fundamental mode propagation through a 20 cm length of passive 300 micrometer core multimode fibre when the input is a well-aligned Gaussian beam. Through careful control of fibre geometry, input beam parameters and alignment, we measured an output M squared of 1.1 + - 0.05. The fibre had a numerical aperture of 0.389, implying a V number of 236.8. To our knowledge, this is the largest core fibre through which diffraction limited fundamental mode propagation has been demonstrated. Although the results presented here relate to undoped fibre, they do provide the practical basis for a new generation of EDFAs and EDFLs.Comment: 5 figure

    Perspectival generation in/within the Sala della Pace: broadening the viewfield of spatialised images

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    It is everyday experience to look at a picture on a wall, (or on a computer screen) from a position that is out of alignment with its perspective, and then make a mental adjustment so as to allow for and ignore the distortion which results. To understand the limits and problem of this compensation it is necessary to look at works where there is an explicit attempt to relate the space of an image and the space in which the image exists. One such exemplar is the Sala della Pace, painted by Ambrogio Lorenzetti in 1338-40. The Sala della Pace may be of particular value today in helping us understand and evaluate the rapidly developing capacity of digital technology to represent dense visual and spatial information. Through Lorenzetti’s amalgam of multiple zones of extromissive generation within the images of the Sala della Pace, Lorenzetti‘s work suggests a potential compositional technique that subverts the reduction of spatial representation to a singular point of perspectival generation by broadening the viewfield in which to receive and construct multiple spatialised images. It is the aim of this paper to explore spatial concepts in Lorenzetti’s painting that may inform the way in which we conceptualise the spatial representation of both real and fictive space in/within images
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