Search results for "Red light"

Vision based attitude and altitude estimation for UAVs in dark environments

2011

This paper presents a system dedicated to the real-time estimation of attitude and altitude for unmanned aerial vehicles (UAV) under low light and dark environment. This system consists in a fisheye camera, which allows to cover a large field of view (FOV), and a laser circle projector mounted on a fixed baseline. The approach, close to structured light systems, uses the geometrical information obtained by the projection of the laser circle onto the ground plane and perceived by the camera. We present a theoretical study of the system in which the camera is modelled as a sphere and show that the estimation of a conic on this sphere allows to obtain the attitude and the altitude of the robot…

A Geometrical Approach for Vision Based Attitude and Altitude Estimation for UAVs in Dark Environments

2012

International audience; This paper presents a single camera and laser system dedicated to the realtime estimation of attitude and altitude for unmanned aerial vehicles (UAV) under low illumination conditions to dark environments. The fisheye camera allows to cover a large field of view (FOV). The approach, close to structured light systems, uses the geometrical information obtained by the projection of a laser circle onto the ground plane and perceived by the camera. We propose some experiments based on simulated data and real sequences. The results show good agreement with the ground truth values from the commercial sensors in terms of its accuracy and correctness. The results also prove i…

Phototherapy: Ruthenium-Containing Block Copolymer Assemblies: Red-Light-Responsive Metallopolymers with Tunable Nanostructures for Enhanced Cellular…

2016

SfM Techniques Applied in Bad Lighting and Reflection Conditions: The Case of a Museum Artwork

2019

In recent years, SfM techniques have been widely used especially in the field of Cultural Heritage. Some applications, however, remain undefined in cases where the boundary conditions are not suitable for the technique. Examples of this are instances where there are poor lighting conditions and the presence of glass and reflective surfaces. This paper presents a case study where SfM is applied, using a DSLR camera (Nikon D5200), to the “Head of Hades” inside a glass theca and under a large number of light sources at different distances and of different intensities and sizes. The geometric evaluation has been made comparing the DSLR camera model against the 3D data acquired with structured l…

Near infrared light to promote synaptic resilience to Alzheimer’s Disease neuropathology

Alzheimer’s Disease (AD) is a multifactorial neurodegenerative dementia with no curative therapeutic options. One of the earliest impairments in AD triggering cognitive decline is the synaptic dysfunction induced by the selective targeting and interruption of the synaptic region by the small oligomeric form of amyloid beta (Aβ). Recently, the co-presence of Aβ oligomers (Aβo) and tau oligomers (tau-o) at the synapses has been suggested to exacerbate this dysfunction. Therefore, the development of therapeutics aimed at protecting the synapses from the toxic binding of both proteins at the synapses can preserve synaptic health and cognitive function. With this goal in mind, the present study …

Machine Learning-Based Classification of Vector Vortex Beams.

2020

Structured light is attracting significant attention for its diverse applications in both classical and quantum optics. The so-called vector vortex beams display peculiar properties in both contexts due to the non-trivial correlations between optical polarization and orbital angular momentum. Here we demonstrate a new, flexible experimental approach to the classification of vortex vector beams. We first describe a platform for generating arbitrary complex vector vortex beams inspired to photonic quantum walks. We then exploit recent machine learning methods -- namely convolutional neural networks and principal component analysis -- to recognize and classify specific polarization patterns. O…

Study of ambient light influence for three-dimensional scanners based on structured light

2007

Ambient light in a scene can introduce errors into range data from most commercial three-dimensional range scanners, particularly scanners that are based on projected patterns and structured lighting. We study the effects of ambient light on a specific commercial scanner. We further present a method for characterizing the range accuracy as a function of ambient light distortions. After a brief review of related research, we first describe the capabilities of the scanner we used and define the experimental setup for our study. Then we present the results of the range characterization relative to ambient light. In these results, we note a systematic error source that appears to be an artifact…

The structural effect between the output module and chromophore-binding domain is a two-way street via the hairpin extension.

2022

AbstractSignal transduction typically starts with either ligand binding or cofactor activation, eventually affecting biological activities in the cell. In red light-sensing phytochromes, isomerization of the bilin chromophore results in regulation of the activity of diverse output modules. During this process, several structural elements and chemical events influence signal propagation. In our study, we have studied the full-length bacteriophytochrome from Deinococcus radiodurans as well as a previously generated optogenetic tool where the native histidine kinase output module has been replaced with an adenylate cyclase. We show that the composition of the output module influences the stabi…

INVESTIGATION OF THE INDENTATION BEHAVIOUR OF FOAM CORED LIGHTWEIGHT COMPOSITE SANDWICHES

2011

Near-infrared imaging and structured light ranging for automatic catheter insertion

2006

Vein localization and catheter insertion constitute the first and perhaps most important phase of many medical procedures. Currently, catheterization is performed manually by trained personnel. This process can prove problematic, however, depending upon various physiological factors of the patient. We present in this paper initial work for localizing surface veins via near-infrared (NIR) imaging and structured light ranging. The eventual goal of the system is to serve as the guidance for a fully automatic (i.e., robotic) catheterization device. Our proposed system is based upon near-infrared (NIR) imaging, which has previously been shown effective in enhancing the visibility of surface vein…