399 research outputs found
Optical recognition of modern and Roman coins
The recently granted EU project COINS aims to contribute substantially to the fight against illegal trade and theft of coins that appears to be a major part of the illegal antiques market. A central component of the permanent identification and traceability of coins is the underlying image recognition technology. However, currently available algorithms focus basically on the recognition of modern coins. To date, no optical recognition system for ancient coins has been successfully researched. It is a challenging task to work with medieval coins since they are – unlike modern coins – not mass manufactured. In this project, the recognition of coins will be based on new algorithms of pattern recognition and image processing, in a field – classification and identification of medieval coins – as yet unexplored. Since the project recently started, preliminary results and work already performed in this field are presented and discussed
Human Action Recognition in Egocentric Perspective Using 2D Object and Hands Pose
Egocentric action recognition is essential for healthcare and assistive
technology that relies on egocentric cameras because it allows for the
automatic and continuous monitoring of activities of daily living (ADLs)
without requiring any conscious effort from the user. This study explores the
feasibility of using 2D hand and object pose information for egocentric action
recognition. While current literature focuses on 3D hand pose information, our
work shows that using 2D skeleton data is a promising approach for hand-based
action classification, might offer privacy enhancement, and could be less
computationally demanding. The study uses a state-of-the-art transformer-based
method to classify sequences and achieves validation results of 94%,
outperforming other existing solutions. The accuracy of the test subset drops
to 76%, indicating the need for further generalization improvement. This
research highlights the potential of 2D hand and object pose information for
action recognition tasks and offers a promising alternative to 3D-based
methods
Strong Optomechanical Squeezing of Light
We create squeezed light by exploiting the quantum nature of the mechanical
interaction between laser light and a membrane mechanical resonator embedded in
an optical cavity. The radiation pressure shot noise (fluctuating optical force
from quantum laser amplitude noise) induces resonator motion well above that of
thermally driven motion. This motion imprints a phase shift on the laser light,
hence correlating the amplitude and phase noise, a consequence of which is
optical squeezing. We experimentally demonstrate strong and continuous
optomechanical squeezing of 1.7 +/- 0.2 dB below the shot noise level. The peak
level of squeezing measured near the mechanical resonance is well described by
a model whose parameters are independently calibrated and that includes thermal
motion of the membrane with no other classical noise sources.Comment: 12 pages, 8 figure
Improved motion segmentation based on shadow detection
In this paper, we discuss common colour models for background subtraction and problems related to their utilisation are discussed. A novel approach to represent chrominance information more suitable for robust background modelling and shadow suppression is proposed. Our method relies on the ability to represent colours in terms of a 3D-polar coordinate system having saturation independent of the brightness function; specifically, we build upon an Improved Hue, Luminance, and Saturation space (IHLS). The additional peculiarity of the approach is that we deal with the problem of unstable hue values at low saturation by modelling the hue-saturation relationship using saturation-weighted hue statistics. The effectiveness of the proposed method is shown in an experimental comparison with approaches based on RGB, Normalised RGB and HSV
3D Acquisition of Archaeological Ceramics and Web-Based 3D Data Storage
Motivated by the requirements of modern archaeology, we are developing an automated system for archaeological classification and reconstruction of ceramics. The goal is to create a tool that satisfies the criteria of accuracy, performance (findings/hour), robustness, transportability, overall costs, and careful handling of the findings. Following our previous work, we present new achievements on the documentation steps for 3D acquisition, 3D data processing, and 3D reconstruction. We have improved our system so that it can handle large quantities of ceramic fragments efficiently and computes a more robust orientation of a fragment. In order to store the sherd data acquired and hold all the information necessary to reconstruct a complete vessel, a database for archaeological fragments was developed. We will demonstrate practical experiments and results undertaken onsite at different excavations in Israel and Peru
In-Situ Dual-Port Polarization Contrast Imaging of Faraday Rotation in a High Optical Depth Ultracold 87Rb Atomic Ensemble
We study the effects of high optical depth and density on the performance of
a light-atom quantum interface. An in-situ imaging method, a dual-port
polarization contrast technique, is presented. This technique is able to
compensate for image distortions due to refraction. We propose our imaging
method as a tool to characterize atomic ensembles for high capacity spatial
multimode quantum memories. Ultracold dense inhomogeneous Rubidium samples are
imaged and we find a resonant optical depth as high as 680 on the D1 line. The
measurements are compared with light-atom interaction models based on
Maxwell-Bloch equations. We find that an independent atom assumption is
insufficient to explain our data and present corrections due to resonant
dipole-dipole interactions
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