Active-passive 44 SOA-based switch with integrated power monitoring

The first monolithically integrated 44 switch with power monitoring function using on-chip PIN photodiodes is reported. Using 10Gb/s signals, under active power control an IPDR of 12dB for a 1dB power penalty is achieved. © 2012 OSA.

A polymeric regenerative optical bus for board-level optical interconnections

A scalable polymer waveguide-based regenerative optical bus architecture for use in board-level communications is presented. As a proof-of-principle demonstration, a 4-channel polymer bus formed on a FR4 substrate providing 10 Gb/s/channel data transmission is reported. © 2012 OSA.

Innovative Stereo Vision-Based Approach to Generate Dense Depth Map of Transportation Infrastructure

Three-dimensional (3-D) spatial data of a transportation infrastructure contain useful information for civil engineering applications, including as-built documentation, on-site safety enhancements, and progress monitoring. Several techniques have been developed for acquiring 3-D point coordinates of infrastructure, such as laser scanning. Although the method yields accurate results, the high device costs and human effort required render the process infeasible for generic applications in the construction industry. A quick and reliable approach, which is based on the principles of stereo vision, is proposed for generating a depth map of an infrastructure. Initially, two images are captured by two similar stereo cameras at the scene of the infrastructure. A Harris feature detector is used to extract feature points from the first view, and an innovative adaptive window-matching technique is used to compute feature point correspondences in the second view. A robust algorithm computes the nonfeature point correspondences. Thus, the correspondences of all the points in the scene are obtained. After all correspondences have been obtained, the geometric principles of stereo vision are used to generate a dense depth map of the scene. The proposed algorithm has been tested on several data sets, and results illustrate its potential for stereo correspondence and depth map generation.

Innovative Stereo Vision-Based Approach to Generate Dense Depth Map of Transportation Infrastructure

Three-dimensional (3-D) spatial data of a transportation infrastructure contain useful information for civil engineering applications, including as-built documentation, on-site safety enhancements, and progress monitoring. Several techniques have been developed for acquiring 3-D point coordinates of infrastructure, such as laser scanning. Although the method yields accurate results, the high device costs and human effort required render the process infeasible for generic applications in the construction industry. A quick and reliable approach, which is based on the principles of stereo vision, is proposed for generating a depth map of an infrastructure. Initially, two images are captured by two similar stereo cameras at the scene of the infrastructure. A Harris feature detector is used to extract feature points from the first view, and an innovative adaptive window-matching technique is used to compute feature point correspondences in the second view. A robust algorithm computes the nonfeature point correspondences. Thus, the correspondences of all the points in the scene are obtained. After all correspondences have been obtained, the geometric principles of stereo vision are used to generate a dense depth map of the scene. The proposed algorithm has been tested on several data sets, and results illustrate its potential for stereo correspondence and depth map generation.

Methods of monitoring of metro lining in Prague

There are several reasons for monitoring of underground structures and they have already been discussed many times, e.g. from the view of ageing or state after accidental event like flooding of Prague metro in 2002. Monitoring of Prague metro is realized in the framework of international research project sponsored by ESF-S3T. The monitoring methods used in Prague are either classical one or new or developing one. The reason for different monitoring methods is the different precision of each method and also for cross-checking between them and their evaluation. Namely we use convergence, tiltmetres, crackmetres, geophysical methods, laser scanning, computer vision and finally installation of MEMS monitoring devices. In the paper more details of each method and obtained results will be presented. The monitoring methods are complemented by wireless data collection and transfer for real-time monitoring. © 2012 Taylor & Francis Group.

Micro-measurement and monitoring system for ageing underground infrastructure (Underground M3)

Advances in the development of computer vision, miniature Micro-Electro-Mechanical Systems (MEMS) and Wireless Sensor Network (WSN) offer intriguing possibilities that can radically alter the paradigms underlying existing methods of condition assessment and monitoring of ageing civil engineering infrastructure. This paper describes some of the outcomes of the European Science Foundation project "Micro-Measurement and Monitoring System for Ageing Underground Infrastructures (Underground M3)". The main aim of the project was to develop a system that uses a tiered approach to monitor the degree and rate of tunnel deterioration. The system comprises of (1) Tier 1: Micro-detection using advances in computer vision and (2) Tier 2: Micro-monitoring and communication using advances in MEMS and WSN. These potentially low-cost technologies will be able to reduce costs associated with end-of-life structures, which is essential to the viability of rehabilitation, repair and reuse. The paper describes the actual deployment and testing of these innovative monitoring tools in tunnels of London Underground, Prague Metro and Barcelona Metro. © 2012 Taylor & Francis Group.

Polymer waveguide-based backplanes for board-level optical interconnects

Optical interconnects are increasingly considered for use in high-performance electronic systems. Multimode polymer waveguides are a promising technology for the formation of optical backplane as they enable cost-effective integration of optical links onto standard printed circuit boards. In this paper, two different types of polymer waveguide-based optical backplanes are presented. The first one implements a passive shuffle architecture enabling non-blocking on-board optical interconnection between different cards/modules, while the second one deploys a regenerative bus architecture allowing the interconnection of an arbitrary number of electrical cards over a common optical bus. The polymer materials and the multimode waveguide components used to form the optical backplanes are presented, while details of the interconnection architectures and design of the backplanes are described. Proof-of-principle demonstrators fabricated onto low-cost FR4 substrates, including a 10-card 1 Tb/s-capacity passive shuffle router and 4-channel 3-card polymeric bus modules, are reported and their optical performance characteristics are presented. Low-loss, low-crosstalk on-board interconnection is achieved and error-free (BER10 12) 10 Gb/s communication between different card/module interfaces is demonstrated in both polymeric backplane systems. © 2012 IEEE.

4-Channel polymeric optical bus module for board-level optical interconnections

A 4-channel polymeric optical bus module suitable for use in board-level interconnections is presented. Low-loss and low-crosstalk module performance is achieved, while -1 dB alignment tolerances better than ± 8 μm are demonstrated. © 2012 OSA.

Multimode 90°-crossings, combiners and splitters for a polymer-based on-board optical bus

The design and characterization of polymer-based multimode 90°-crossings, combiners and splitters exhibiting excess losses below 0.1 dB/crossing, 2 dB and 3 dB respectively are reported. The devices enable the realization of an on-board optical bus. © 2012 OSA.

ChESS - Quick and Robust Detection of Chess-board Features

Localization of chess-board vertices is a common task in computer vision, underpinning many applications, but relatively little work focusses on designing a specific feature detector that is fast, accurate and robust. In this paper the `Chess-board Extraction by Subtraction and Summation' (ChESS) feature detector, designed to exclusively respond to chess-board vertices, is presented. The method proposed is robust against noise, poor lighting and poor contrast, requires no prior knowledge of the extent of the chess-board pattern, is computationally very efficient, and provides a strength measure of detected features. Such a detector has significant application both in the key field of camera calibration, as well as in Structured Light 3D reconstruction. Evidence is presented showing its robustness, accuracy, and efficiency in comparison to other commonly used detectors both under simulation and in experimental 3D reconstruction of flat plate and cylindrical objects

Compact multimode polymer waveguide bends for board-level optical interconnects

Multimode polymer waveguides are promising for use in board-level optical interconnects. In recent years, various on-board optical interconnection architectures have been demonstrated making use of passive routing waveguide components. In particular, 90° bends have played important roles in complex waveguide layouts enabling interconnection between non co-linear points on a board. Due to the dimensions and index step of the waveguides typically used in on-board optical interconnects, low-loss bends are typically limited to a radius of ∼ 10 mm. This paper therefore presents the design and fabrication of compact low-loss waveguide bends with reduced radii of curvature, offering significant reductions in the required areas for on-board optical circuits. The proposed design relies on the exposure of the bend section to the air, achieving tighter light confinement along the bend and reduced bending losses. Simulation studies carried out with ray tracing tools and experimental results from polymer samples fabricated on FR4 are presented. Low bending losses are achieved from the air-exposed bends up to 4 mm of radius of curvature, while an improvement of 14 μm in the 1 dB alignment tolerances at the input of these devices (fibre to waveguide coupling) is also obtained. Finally, the air-exposed bends are employed in an optical bus structure, offering reductions in insertion loss of up to 3.8 dB. © 2013 IEEE.

Demonstration of cascaded operation of active-passive integrated 4×4 SOA switches with on-chip monitoring for power control and energy consumption optimization

Cascaded 4×4 SOA switches with on-chip power monitoring exhibit potential for lowpower 16×16 integrated switches. Cascaded operation at 10Gbit/s with an IPDR of 8.5dB and 79% lower power consumption than equivalent all-active switches is reported © 2013 OSA.