Search results for "detector"
showing 10 items of 3491 documents
Are simple striate cells analysers of visual signals both in spatial position as well as in spatial frequency?
1984
According to a modern view, simple cells of the cat striate cortex are considered to operate as apart of Fourier analysis system thus leading to the idea that the operational mechanism of the visual cortex is concerned with the analysis of spatial frequencies. Nevertheless if simple cells are really concerned only with the analysis of spatial frequencies there should exist a strict relationship between their spatial frequency selectivity and the spatial organization of their receptive fields. This is because it is the spatial organization of the spatial frequency detector i.e. the cell's receptive field that determines the cell's spatial frequency selectivity. Since the quantitative analysi…
The Athena X-ray Integral Field Unit (X-IFU)
2016
Event: SPIE Astronomical Telescopes + Instrumentation, 2016, Edinburgh, United Kingdom.
Vertical scratches detection based on edge detection for old film
2010
Automatic detection of image damaged regions is the key to automatic video image inpainting. Vertical scratches are the common damages in the old film. In this paper, a vertical scratches detection algorithm based on edge detection is proposed. The proposed algorithm first uses the operator which has the largest response to the vertical edge in Sobel operator to detect edges, and then uses canny operator to detect edges further. Third, we detect vertical lines in the image through probabilistic Hough transform. Finally, we obtain the true locations of the vertical lines scratches through morphology and width constraints. Many experiments show that our method can detect vertical line scratch…
Hand Detection and Tracking Using the Skeleton of the Blob for Medical Rehabilitation Applications
2012
This article presents an image processing application for hand detection and tracking using the 4-connected skeleton of the segmentation mask. The system has been designed to be used with techniques of virtual reality to develop an interactive application for phantom limb pain reduction in therapeutic treatments. One of the major contributions is the design of a fast and accurate skeleton extractor, that has proven to be faster than those available in the literature. The skeleton allows the system to precisely detect the position of all the interest points of the hand (namely the fingers and the hand center). The system, composed of both the hand detector and tracker, and the virtual realit…
The Detector Control of the PANDA Experiment
2014
The PANDA experiment will be built at the antiproton storage ring HESR, a part of the new accelerator facility FAIR in Darmstadt, Germany. PANDA aims amongst other topics for high precision measurements in hadron spectroscopy and search for exotic matter. To guarantee the high resolution of the different components a detector control system (DCS) monitoring temperatures, humidity, pressure, and controlling chillers and power supplies is needed. The DCS of PANDA is built using the open-source software package EPICS (Experimental Physics and Industrial Control System) with a PANDA specific version of Control-System Studio. In this document the general concepts of the PANDA DCS will be discuss…
Ridge-line optimal detector
2000
Image processing techniques have seen many developments in recent years. Starting from the pioneering work of Canny, Deriche developed a second order recursive filter capable of detecting stepped contours. However, there are other contour shapes that those filters struggle to detect. We describe a new optimal filter sensu Canny for detecting ridge-line contours. This is a third order recursive and even filter. It is dependent on three parameters by which detection accuracy is adjusted. The results obtained by applying this filter to (possibly noise- affected) images are compared with those in the work by Ziou. © 2000 Society of Photo-Optical Instrumentation Engineers. (S0091-3286(00)00706-6)
Feature selection using support vector machines and bootstrap methods for ventricular fibrillation detection
2012
Early detection of ventricular fibrillation (VF) is crucial for the success of the defibrillation therapy in automatic devices. A high number of detectors have been proposed based on temporal, spectral, and time-frequency parameters extracted from the surface electrocardiogram (ECG), showing always a limited performance. The combination ECG parameters on different domain (time, frequency, and time-frequency) using machine learning algorithms has been used to improve detection efficiency. However, the potential utilization of a wide number of parameters benefiting machine learning schemes has raised the need of efficient feature selection (FS) procedures. In this study, we propose a novel FS…
ERP qualification exploiting waveform, spectral and time-frequency infomax
2008
The present contribution briefly introduces an event related potential (ERP) detector. The specified detector includes three kinds of features of ERP. They are the ERP waveform feature, ERP spectral feature and ERP time-frequency feature respectively. According to these characteristics, two parameters are defined to reflect the timing feature of ERP. The mismatch negativity (MMN) is taken as the example to design an exact qualification detector. The experiment validates that the computer can automatically detect the raw trace to reflect the quality of the dataset, qualify the filtered trace to test whether the artifacts have been filtered out, and select the ERP-like component to reject art…
Effects of high pressure on the optical absorption spectrum of scintillating PbWO4 crystals
2006
The pressure behavior of the absorption edge of PbWO4 was studied up to 15.3 GPa. It red-shifts at -71 meV/GPa below 6.1 GPa, but at 6.3 GPa the band-gap collapses from 3.5 eV to 2.75 eV. From 6.3 GPa to 11.1 GPa, the absorption edge moves with a pressure coefficient of -98 meV/GPa, undergoing additional changes at 12.2 GPa. The results are discussed in terms of the electronic structure of PbWO4 which attribute the behavior of the band-gap to changes in the local atomic structure. The changes observed at 6.3 GPa and 12.2 GPa are attributed to phase transitions.
Bulk sensitive photo emission spectroscopy of C1b compounds
2006
This work reports about bulk-sensitive, high energy photoelectron spectroscopy from the valence band of CoTiSb excited by photons from 1.2 to 5 keV energy. The high energy photoelectron spectra were taken at the KMC-1 high energy beamline of BESSY II employing the recently developed Phoibos 225 HV analyser. The measurements show a good agreement to calculations of the electronic structure using the LDA scheme. It is shown that the high energy spectra reveal the bulk electronic structure better compared to low energy XPS spectra.