Consulta: subjectFacets:"Optics"
Registros recuperados: 3
Data/hora: 13/06/2024 02:53:23

Application du laser a la detection sous-marine: Experimentation d'un imageur
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Kervern, G; Legall, A.
Nowadays, side-looking sonar is the only equipment able to carry out long-range underwater imaging. The use of optics is limited to short-range identification by means of conventional video-cameras. However, active optical systems (lidars) manufacturing, using a blue-green laser, will enable optics to hold its place in the field of long-range underwater imaging. After a short comparison between acoustics and optics in underwater detection and a description of the proper features of underwater optical propagation, we present the different conceivable imaging principles and propose a method to determine their performances. The experimentations described concern a lidar imager mock-up using one of the imaging principles proposed. The pictures obtained deal...
Tipo: Text
Palavras-chave: Optics; Lasers; Detection; Acoustics; Underwater cameras; Sonar imagery; Imaging techniques; Underwater photography; Marine technology; Side scan sonar.
Ano: 1990
URL: http://archimer.ifremer.fr/doc/1990/acte-1139.pdf

Glider-Based Active Acoustic Monitoring of Currents and Turbidity in the Coastal Zone
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Gentil, Mathieu; Many, Gaël; Durrieu De Madron, Xavier; Cauchy, Pierre; Pairaud, Ivane; Testor, Pierre; Verney, Romaric; Bourrin, François.
The recent integration of Acoustic Doppler Current Profilers (ADCPs) onto underwater gliders changes the way current and sediment dynamics in the coastal zone can be monitored. Their endurance and ability to measure in all weather conditions increases the probability of capturing sporadic meteorological events, such as storms and floods, which are key elements of sediment dynamics. We used a Slocum glider equipped with a CTD (Conductivity, Temperature, Depth), an optical payload, and an RDI 600 kHz phased array ADCP. Two deployments were carried out during two contrasting periods of the year in the Rhone River region of freshwater influence (ROFI). Coastal absolute currents were reconstructed using the shear method and bottom tracking measurements, and...
Tipo: Text
Palavras-chave: Glider; Optics; Acoustics; Satellite; Coastal hydrodynamics; Suspended particulate matter; Particulate fluxes; Gulf of Lions; Mediterranean.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00648/76039/76962.pdf

Leaf area estimation of medium size plants using optical metrology
Provedor de dados: Revista Brasileira de Engenharia Agrícola e Ambiental
Autores: Ribeiro,Kleber M.; Braga,Roberto A.; Scalco,Myriane S.; Horgan,Graham W.
The total leaf area (TLA) estimation is an important feature of the crops and their assessment a challenge, since the direct methods of obtaining it are destructive and time consuming. Non-destructive methods have been explored to obtain the TLA by indirect approaches, in turn creating other features, as the leaf area index. The development of non-destructive technology to access the TLA of a plant has been the subject of much research, and the optical metrology is an promising approach. In this work, some indirect methods associated with optical approaches were evaluated as an alternative to obtain the TLA of the coffee plant. Commercial equipment were used, such as a camera with a fish eye lens and lux meters, associated to the sizes of the canopies were...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Optics; Non-destructive technique; Coffee.
Ano: 2013
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662013000600004