Video camera

A video camera is an optical instrument that captures videos (as opposed to a movie camera, which records images on film). Video cameras were initially developed for the television industry but have since become widely used for a variety of other purposes. Video cameras are used primarily in two modes. The first, characteristic of much early broadcasting, is live television, where the camera feeds real time images directly to a screen for immediate observation. A few cameras still serve live television production, but most live connections are for security, military/tactical, and industrial operations where surreptitious or remote viewing is required. In the second mode the images are recorded to a storage device for archiving or further processing; for many years, videotape was the primary format used for this purpose, but was gradually supplanted by optical disc, hard disk, and then flash memory. Recorded video is used in television production, and more often surveillance and mon

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Investigation of the Electromechanical Properties of Graphene

Mohamed Malik Benameur

This thesis studies the optical and electro-mechanical properties of novel atomically thin crystals. It deals with the carbon based material, graphene, and with layered transition metal dichalcogenides with the common formula MX2. The first part describes a new optical model for detecting ultra-thin, two dimensional nanocrystals under optical microscope. A simple optical model is used to calculate the contrast of nanolayers on SiO2. The model is extended for imaging using the green channel of a video camera. Atomic force microscopy combined with optical imaging confirms that single layers of graphene, MoS2, WSe2 and NbSe2 are detectable on 90 nm and 270 nm SiO2. The optical contrast of multi-layer nanocrystals is also reported and allows easy differentiation between single, double and triple layers. Optical imaging is proposed as a rapid, non invasive and low cost method for the detection of ultra-thin nanocrystals. The second part is devoted to studying the electromechanical properties of mono-layer and bilayer graphene. The interplay between the mechanical and the electrical properties of graphene nanoribbons is probed by nanoindentation techniques based on AFM. Deflection of monolayer graphene nanoribbons with widths ranging between 60 nm and 300 nm results in a linear increase in their electrical resistance. The sensitivity of the response increases for nar- rower ribbons and variations of the resistance up to 15% are measured. The electromechanical response of bilayer graphene shows a superposition of a linear response with oscillations of the electrical resistance. We present possible scenarios to explain the origin of these oscillations.

EPFL2012

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Autonomous Detection and Deterrence of Pigeons on Buildings by Drones

Dario Floreano, Dominik Natter, Fabrizio Schiano, Davide Zambrano

Pigeons may transmit diseases to humans and cause damages to buildings, monuments, and other infrastructure. Therefore, several control strategies have been developed, but they have been found to be either ineffective or harmful to animals and often depend on human operation. This study proposes a system capable of autonomously detecting and deterring pigeons on building roofs using a drone. The presence and position of pigeons were detected in real time by a neural network using images taken by a video camera located on the roof. Moreover, a drone was utilized to deter the animals. Field experiments were conducted in a real-world urban setting to assess the proposed system by comparing the number of animals and their stay durations for over five days against the 21-day- trial experiment without the drone. During the five days of experiments, the drone was automatically deployed 55 times and was significantly effective in reducing the number of birds and their stay durations without causing any harm to them. In conclusion, this study has proven the effectiveness of this system in deterring birds, and this approach can be seen as a fully autonomous alternative to the already existing methods.

2022

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Visibility of dichalcogenide nanolayers

Mohamed Malik Benameur, Helmuth Berger, Andras Kis, Branimir Radisavljevic

Dichalcogenides with the common formula MX2 are layered materials with electrical properties that range from semiconducting to superconducting. Here, we describe optimal imaging conditions for the optical detection of ultrathin, two-dimensional dichalcogenide nanocrystals containing single, double and triple layers of MoS2, WSe2 and NbSe2. A simple optical model is used to calculate the contrast for nanolayers deposited on wafers with varying thicknesses of SiO2. The model is extended for imaging using the green channel of a video camera. Using AFM and optical imaging we confirm that single layers of MoS2 and WSe2 can be detected on 90 and 270 nm SiO2 using optical means. By measuring contrast under broadband green illumination we are also able to distinguish between nanostructures containing single, double and triple layers of MoS2 and WSe2. We observe and discuss discrepancies in the case of NbSe2.

Institute of Physics2011

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EE-519: Bioelectronics and biomedical microelectronics

The course covers the fundaments of bioelectronics and integrated microelectronics for biomedical and implantable systems. Issues and trade-offs at the circuit and systems levels of invasive microelectronic systems as well as their eluding designs, methods and classical implementations are discussed

EE-584: Spacecraft design and system engineering

The main objective of the course is to introduce the concept of space system design and engineering. The course will describe the various subsystems involved in the design of a satellite. It will also describe the techniques of systems engineering that are used to obtain a coherent satellite design.

DH-500: Computational Social Media

The course integrates concepts from media studies, machine learning, multimedia and network science to characterize social practices and analyze content in sites like Facebook, Twitter and YouTube. Students will learn computational methods to infer individual and networked phenomena in social media.

Appareil photographique numérique

Un appareil photographique numérique (ou APN) est un appareil photographique qui recueille la lumière sur un capteur photographique électronique, plutôt que sur une pellicule photographique, et qui c

Transformée en cosinus discrète

La transformée en cosinus discrète ou TCD (de l'anglais : DCT ou Discrete Cosine Transform) est une transformation proche de la transformée de Fourier discrète (DFT). Le noyau de projection est un cos

Capteur photographique CCD

vignette|Capteur photographique CCD pour l'imagerie astronomique. Un capteur photographique CCD est un capteur photographique basé sur un dispositif à transfert de charges (charge coupled device, CCD)