Vanishing point detection for visual surveillance systems in railway platform environments

© 2018 Elsevier B.V. Visual surveillance is of paramount importance in public spaces and especially in train and metro platforms which are particularly susceptible to many types of crime from petty theft to terrorist activity. Image resolution of visual surveillance systems is limited by a trade-off between several requirements such as sensor and lens cost, transmission bandwidth and storage space. When image quality cannot be improved using high-resolution sensors, high-end lenses or IR illumination, the visual surveillance system may need to increase the resolving power of the images by software to provide accurate outputs such as, in our case, vanishing points (VPs). Despite having numerous applications in camera calibration, 3D reconstruction and threat detection, a general method for VP detection has remained elusive. Rather than attempting the infeasible task of VP detection in general scenes, this paper presents a novel method that is fine-tuned to work for railway station environments and is shown to outperform the state-of-the-art for that particular case. In this paper, we propose a three-stage approach to accurately detect the main lines and vanishing points in low-resolution images acquired by visual surveillance systems in indoor and outdoor railway platform environments. First, several frames are used to increase the resolving power through a multi-frame image enhancer. Second, an adaptive edge detection is performed and a novel line clustering algorithm is then applied to determine the parameters of the lines that converge at VPs; this is based on statistics of the detected lines and heuristics about the type of scene. Finally, vanishing points are computed via a voting system to optimize detection in an attempt to omit spurious lines. The proposed approach is very robust since it is not affected by ever-changing illumination and weather conditions of the scene, and it is immune to vibrations. Accurate and reliable vanishing point detection provides very valuable information, which can be used to aid camera calibration, automatic scene understanding, scene segmentation, semantic classification or augmented reality in platform environments

A profile measurement system for rail quality assessment during manufacturing

Steel rails used in the transport sector and in industry are designed and manufactured to support high stress levels generated by high-speed and heavy-loaded modern trains. In the rail manufacturing process, one of the key stages is rolling, where fast, accurate and repeatable rail profile measurement is a major challenge. In this paper, a rail profile measurement system for rail rolling mills based on four conventional, inexpensive laser range finders is proposed. The range finders are calibrated using a common reference to properly express the point clouds generated by each range finder in the world coordinate system. The alignment of the point clouds to the rail model is performed by means of an efficient and robust registration method. Experiments carried out in a rail rolling mill demonstrate the accuracy and repeatability of the system; the maximum error is below 0.12%. All parallelizable tasks were designed and developed to be executed concurrently, achieving an acquisition rate of up to 210 fp

Infrared Thermography for Temperature Measurement and Non-Destructive Testing

The intensity of the infrared radiation emitted by objects is mainly a function of their temperature. In infrared thermography, this feature is used for multiple purposes: as a health indicator in medical applications, as a sign of malfunction in mechanical and electrical maintenance or as an indicator of heat loss in buildings. This paper presents a review of infrared thermography especially focused on two applications: temperature measurement and non-destructive testing, two of the main fields where infrared thermography-based sensors are used. A general introduction to infrared thermography and the common procedures for temperature measurement and non-destructive testing are presented. Furthermore, developments in these fields and recent advances are reviewed

Historia y Derecho - Tomo 2: 200 años de república visto desde el altiplano del sur peruano

Capítulos de libros sobre historia del Derecho y otros en la región de Puno

Estudio completo del aprovechamiento de las malezas de los montes "Guadahornillos" y "Vertientes del Guadalquivir" de la Sierra de Cazorla (Jaén)

La zona llamada de malezas ocupa en los montea do la Sierra de Cazorla (Jaén) una extensión considerable, no bien delimitada que - se aproxima a las 5 ó 6000 Has

Structured-Light Sensor Using Two Laser Stripes for 3D Reconstruction without Vibrations

3D reconstruction based on laser light projection is a well-known method that generally provides accurate results. However, when this method is used for inspection in uncontrolled environments, it is greatly affected by vibrations. This paper presents a structured-light sensor based on two laser stripes that provides a 3D reconstruction without vibrations. Using more than one laser stripe provides redundant information than is used to compensate for the vibrations. This work also proposes an accurate calibration process for the sensor based on standard calibration plates. A series of experiments are performed to evaluate the proposed method using a mechanical device that simulates vibrations. Results show excellent performance, with very good accuracy

Indoor Air Quality Monitoring Sensor for the Web of Things

Many Internet of Things platforms use dedicated software coupled with proprietary devices and interfaces, creating silo solutions with no interoperability. The Web of Things paradigm promotes using open Web standards to connect physical objects to the Internet through an application layer. In this paper, we propose a low-cost, indoor air quality monitoring sensor implementing a minimal servient building block recommended by the Web of Things Working Group of the World Wide Web Consortium. The proposed sensor runs a Web server on a low-power system-on-chip microcontroller, which provides temperature, relative humidity and carbon dioxide measurements to the Internet through a REST API. Any client on the Internet able to manage the HTTP protocol may access this sensor, making it compatible with any air quality monitoring platform that uses HTTP