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Concept

Angle de champ

En photographie, l'angle de champ (en anglais, angle of view ou AOV) est l'angle que peut capter un dispositif optique. Photographie L'angle de champ est lié à la valeur de la distance focale utilisée et à la taille de la surface sensible. Une courte focale (objectif grand angle) fournira un grand angle de champ, alors qu'une longue focale (téléobjectif) donnera au contraire un angle de champ faible. thumb L'angle de champ α couvert par un appareil de prise de vue peut être calculé au moyen de la fonction mathématique arc tangente selon la formule : \alpha = 2 \cdot \arctan \left(\frac{d} {2\cdot f}\right).

d est la longueur d'un bord ou de la diagonale de l'image optique (supposée de forme rectangulaire), c'est-à-dire de la pellicule ou du capteur de l'appareil ;
f est la focale de l'objectif ;
arctan est la fonction arc tangente.

Avec une longue focale, l'angle étant petit, la formule approchée devient : \alpha \approx \tfrac {180}{

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Résumé

d est la longueur d'un bord ou de la diagonale de l'image optique (supposée de forme rectangulaire), c'est-à-dire de la pellicule ou du capteur de l'appareil ;
f est la focale de l'objectif ;
arctan est la fonction arc tangente.

Avec une longue focale, l'angle étant petit, la formule approchée devient : \alpha \approx \tfrac {180}{

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Caméra

thumb|Arrière de la caméra argentique Mitchell BNC dotée en supplément sur le côté droit d'un enregistreur vidéo analogique, utilisée par Stanley Kubrick pour pouvoir rapidement monter un "brouillon"

Objectif photographique

vignette|Gauche : 1:2.8/50 MacroCentre : 1:4-5.6/70-300 Droite : 1:4-5.6/10-20 Un objectif photographique est un système optique convergent formé de plusieurs lentilles, et éventuellement

Objectif grand angle

Un objectif grand angle est un objectif à courte focale. L'effet de cette courte focale est de permettre un cadrage large d'objets rapprochés dont on ne peut pas s'éloigner. Par exemple, il peut se

Super-resolution imaging of multiple cells by optimized flat-field epi-illumination

Anna Archetti, Kyle Michael Douglass, Ambroise Justin Lambert, Suliana Manley, Christian Sieben

Biological processes are inherently multi-scale, and supramolecular complexes at the nanoscale determine changes at the cellular scale and beyond. Single-molecule localizationmicroscopy (SMLM)(1-3) techniques have been established as important tools for studying cellular features with resolutions of the order of around 10 nm. However, in their current form these modalities are limited by a highly constrained field of view (FOV) and field-dependent image resolution. Here, we develop a low-cost microlens array (MLA)-based epi-illumination system-flat illumination for field-independent imaging (FIFI)-that can efficiently and homogeneously perform simultaneous imaging of multiple cells with nanoscale resolution. The optical principle of FIFI, which is an extension of the Kohler integrator, is further elucidated and modelled with a new, free simulation package. We demonstrate FIFI's capabilities by imaging multiple COS-7 and bacteria cells in 100 x 100 mu m(2) SMLM images-more than quadrupling the size of a typical FOV and producing near-gigapixel-sized images of uniformly high quality.

Nature Publishing Group2016

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Real-time high-resolution omnidirectional imaging platform for drone detection and tracking

Bilal Demir, Selman Ergünay, Yusuf Leblebici, Gökçen Nurlu, Vladan Popovic, Jean-Philippe Thiran

Drones have become steadily affordable, which raises privacy and security concerns as well as interest in drone detection systems. On the other hand, drone detection is a challenging task due to small dimensions of drones, difficulty of long-distance detection, strict real-time constraints and necessity of wide angle coverage for drones. Although different radar and audio-assisted drone detection systems have been presented, they suffer from the cost, range, or interference problems. On the contrary, a long-range detection can be obtained by a vision-based system. Aiming that, we propose a real-time moving object detection and tracking system optimized for drone detection using 16 cameras with 20 MP resolution. The proposed system detects drones from short range and long range with 360 degrees surveillance coverage owing high-performance ultra-high-resolution (320 MP) video-processing capability. It is able to detect drones with 100 cm diameter from 700 m distance despite deceptive background. It is interference free, so multiple systems can properly operate in the vicinity without effecting each other. It integrates processing power of embedded systems with flexibility of software to generate a full platform for drone detection and tracking.

SPRINGER HEIDELBERG2019

Chargement

Modeling and Analysis of a Direct Time-of-Flight Sensor Architecture for LiDAR Applications

Edoardo Charbon, Preethi Padmanabhan, Chunmin Zhang

Direct time-of-flight (DTOF) is a prominent depth sensing method in light detection and ranging (LiDAR) applications. Single-photon avalanche diode (SPAD) arrays integrated in DTOF sensors have demonstrated excellent ranging and 3D imaging capabilities, making them promising candidates for LiDARs. However, high background noise due to solar exposure limits their performance and degrades the signal-to-background noise ratio (SBR). Noise-filtering techniques based on coincidence detection and time-gating have been implemented to mitigate this challenge but 3D imaging of a wide dynamic range scene is an ongoing issue. In this paper, we propose a coincidence-based DTOF sensor architecture to address the aforementioned challenges. The architecture is analyzed using a probabilistic model and simulation. A flash LiDAR setup is simulated with typical operating conditions of a wide angle field-of-view (FOV = 40 ∘ ) in a 50 klux ambient light assumption. Single-point ranging simulations are obtained for distances up to 150 m using the DTOF model. An activity-dependent coincidence is proposed as a way to improve imaging of wide dynamic range targets. An example scene with targets ranging between 8–60% reflectivity is used to simulate the proposed method. The model predicts that a single threshold cannot yield an accurate reconstruction and a higher (lower) reflective target requires a higher (lower) coincidence threshold. Further, a pixel-clustering scheme is introduced, capable of providing multiple simultaneous timing information as a means to enhance throughput and reduce timing uncertainty. Example scenes are reconstructed to distinguish up to 4 distinct target peaks simulated with a resolution of 500 ps. Alternatively, a time-gating mode is simulated where in the DTOF sensor performs target-selective ranging. Simulation results show reconstruction of a 10% reflective target at 20 m in the presence of a retro-reflective equivalent with a 60% reflectivity at 5 m within the same FOV.

2019

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MICRO-505: Organic and printed electronics

This course addresses the implementation of organic and printed electronics technologies using large area manufacturing techniques. It will provide knowledge on materials, printing techniques, devices, systems, and applications: state of the art and current status on commercialization.

PHYS-405: Experimental methods in physics

The course's objectivs are: Learning several advenced methods in experimental physics, and critical reading of experimental papers.

MICRO-561: Biomicroscopy I

Introduction to geometrical and wave optics for understanding the principles of optical microscopes, their advantages and limitations. Describing the basic microscopy components and the commonly used biomicrocopy methods such as widefield and fluorescence.