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oe1(光电查) - 科学论文

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出版时间
  • 2015
研究主题
  • Calibration process of OSL detectors
  • Iodine-131
  • OSL-BeO
  • Dosimetry of staff and patients
  • Optically Stimulated Luminescence (OSL)
应用领域
机构单位
  • Akdeniz University
316 条数据
?? 中文（中国） ▾

  • [IEEE 2018 48th European Microwave Conference (EuMC) - Madrid, Spain (2018.9.23-2018.9.27)] 2018 48th European Microwave Conference (EuMC) - A Unified, Wave-Based Calibration Framework for Vector Network Analyzers

    摘要： The state of the art in Vector Network Analyzer calibrations shows the existence of a separate calibration method and algorithm for each possible combination of standards used during the calibration. In this work, we propose a single, uni?ed calibration framework that can handle most current calibrations using one framework and one algorithm only. The method uses raw wave measurements only, which enables the integration of any potential calibration element and a subsequent power and/or phase calibration as is required for nonlinear VNA measurements.

    关键词： Vector network analyzer,RF-measurements,S-parameters,Voltage waves,Calibration

    更新于2025-09-09 09:28:46

  • Workshop on Lunar Calibration for Satellite Remote Sensing

    摘要： Tracking climate variables at the levels of precision and accuracy required to detect global change requires satellite sensors to make highly consistent measurements that can be compared to measurements made at different times and with different instruments. Gaps in climate data records, such as those resulting from launch delay or instrument failure, and inconsistencies in radiometric scales between satellites can introduce unnecessary measurement error and thus undermine the credibility of fundamental climate data records. To address these issues, leading experts in satellite remote sensing and lunar observation and modeling assembled at the National Institute of Standards and Technology from 12-15 May 2012 for a workshop to discuss the utility of and strategies for using the Moon to calibrate satellite remote sensing measurements. This report summarizes the outcome of the workshop, including suggested steps to maximize the value of the Moon as an exoatmospheric calibration source for satellite remote sensing.

    关键词： lunar spectral irradiance,remote sensing,calibration,moon,radiometry

    更新于2025-09-09 09:28:46

  • An effective method for camera calibration in defocus scene with circular gratings

    摘要： Conventional camera calibrations with circular patterns always require sharp target images and thus fail if the images are blurred. In this paper, we present an effective calibration approach using three circular gratings, which can be employed in defocus scene. Rather than using the concentric circles as the targets, the proposed method utilizes circular gratings generated by phase-shifting methods. The intrinsic parameters of the camera can be obtained with the images of circular points, and it works even if the camera is out-of-focus. Numerical simulation and real data experiments have been carried out to validate the method. And the results show that our method can calibrate the camera effectively even under severe defocus. Moreover, the entire process requires no metric measurement of the test pattern, which is very flexible to implement and suitable for people who are not familiar with computer vision.

    关键词： Phase-shifting,Camera calibration,Defocus,Concentric circles

    更新于2025-09-09 09:28:46

  • Towards a new image processing system at Wendelstein 7-X: From spatial calibration to characterization of thermal events

    摘要： Wendelstein 7-X (W7-X) is the most advanced fusion experiment in the stellarator line and is aimed at proving that the stellarator concept is suitable for a fusion reactor. One of the most important issues for fusion reactors is the monitoring of plasma facing components when exposed to very high heat loads, through the use of visible and infrared (IR) cameras. In this paper, a new image processing system for the analysis of the strike lines on the inboard limiters from the first W7-X experimental campaign is presented. This system builds a model of the IR cameras through the use of spatial calibration techniques, helping to characterize the strike lines by using the information given by real spatial coordinates of each pixel. The characterization of the strike lines is made in terms of position, size, and shape, after projecting the camera image in a 2D grid which tries to preserve the curvilinear surface distances between points. The description of the strike-line shape is made by means of the Fourier Descriptors.

    关键词： fusion reactor,infrared cameras,Fourier Descriptors,stellarator,Wendelstein 7-X,strike lines,image processing,spatial calibration

    更新于2025-09-09 09:28:46

  • A quad polarimetric SAR calibration algorithm using rotation symmetry

    摘要： Polarimetric calibration, precisely deciphering the polarimetric information hidden in the polarized characteristics of a radar scene, is the core step before applying quad polarimetric synthetic aperture radar (PolSAR) data for ground parameter inversion and classification. The previously published techniques for polarimetric calibration generally use at least one known point calibration target to completely determine the polarimetric distortions (cross-talks and channel imbalances) between the various polarized channels. This paper describes a novel method that solely relies on the image itself with the property of rotation symmetry. The algorithm derives the entire cross-talk and channel imbalance parameters using an iterative operation to circularly modify the observed average covariance matrix, which is independent on the known point calibration targets in the illuminated scene. The proposed method is validated to be reliable and efficient through polarimetric calibration experiments using the airborne C-band and RadarSat-2 quad polarimetric SAR images. The experimental results indicate that the new technique achieves similar calibration precision to the Ainsworth algorithm but without using any known calibration point target.

    关键词： Polarimetric calibration,cross-talk,channel imbalance,quad polarimetric SAR,rotation symmetry

    更新于2025-09-09 09:28:46

  • The Warm Electron Beam Ion Trap (WEBIT): An instrument for ground calibration of space-borne x-ray spectrometers

    摘要： The warm electron beam ion trap (WEBIT) at Lawrence Livermore National Laboratory is being developed as a pre-launch, ground calibration source for space-borne, high-throughput, high-resolution x-ray spectrometers, such as the x-ray imaging and spectroscopy mission Resolve quantum calorimeter. Historically, calibration sources for calorimeter spectrometers have relied on characteristic line emission from x-ray tubes, fluorescing metals, and radioactive sources. The WEBIT, by contrast, relies on emission from x-ray transitions in highly charged ions, for example, hydrogen-like and helium-like ions, whose energies are well known and whose line shapes are relatively simple. The WEBIT can create astrophysically relevant ions whose x-ray emission falls in the 0.3-12 keV science bandpass of Resolve and has a portable design advantageous for a calibration source. The WEBIT will be used to help calibrate Resolve’s instrumental line shape and gain scale as a function of various operational parameters during both detector subsystem level testing and instrumental level testing.

    关键词： calibration source,highly charged ions,x-ray spectrometers,electron beam ion trap,WEBIT

    更新于2025-09-09 09:28:46

  • [IEEE 2018 IEEE 3rd Optoelectronics Global Conference (OGC) - Shenzhen, China (2018.9.4-2018.9.7)] 2018 IEEE 3rd Optoelectronics Global Conference (OGC) - Large Field of View Binocular Stereo Vision Sensor Calibration Method Based on 3D Virtual Target

    摘要： In this paper, to address the problem of high calibration accuracy for the binocular stereo vision sensor of large field of view, a binocular stereo vision sensor calibration method using a three-dimensional virtual target constructed by a precision two-axis turntable, laser tracker and a single calibration reference point is studied. The precision two-axis turntable drives the camera capturing a fixed single optical reference point to make two-dimensional rotation, which construct a precise reference control field and achieve calibration. The internal and external reference calibration of the binocular stereo vision sensor is automatically and efficiently completed by the program control, so the method does not need to adjust or know the positional relationship between the reference point and the camera or the turntable. The error simulation analysis and calibration experiments verify that the calibration method proposed in this paper has high reliability and calibration accuracy.

    关键词： binocular stereo vision sensor,large field of view calibration,precision two-axis turntable,laser tracker,3D virtual target

    更新于2025-09-09 09:28:46

  • A Novel Channel Calibration Method for Bistatic ISAR Imaging System

    摘要： In practical bistatic inverse synthetic aperture radar (ISAR) imaging systems, the echo signals are modulated by non-ideal amplitude and phase characteristics of the transmitting and receiving channels, which seriously distorts image quality. However, the conventional channel calibration method based on a transponder is not applicable to bistatic ISAR imaging systems, since the baseline of the system is up to hundreds of kilometers. A channel calibration method only using calibration satellite echo information is proposed for the system, with a linear frequency modulation (LFM) waveform. Firstly, echoes of the calibration satellite are collected by tracking the satellite and multi-period echoes are aligned in the time domain, according to the pulse compression result. Then, the signal to noise ratio (SNR) is improved by accumulating multi-period echoes coherently in the time domain and the calibration coef?cient is constructed based on the accumulated signal. Finally, spectrum of the echo signal is multiplied with the calibration coef?cient to compensate the in?uence of channel characteristics. The effectiveness of the proposed method is veri?ed by the simulation experiment with real satellite echoes.

    关键词： channel calibration,bistatic inverse synthetic aperture radar,external calibration,coherent accumulation

    更新于2025-09-04 15:30:14

  • Imager-to-radiometer in-flight cross calibration: RSP radiometric comparison with airborne and satellite sensors

    摘要： This work develops a method to compare the radiometric calibration between a radiometer and imagers hosted on aircraft and satellites. The radiometer is the airborne Research Scanning Polarimeter (RSP), which takes multi-angle, photo-polarimetric measurements in several spectral channels. The RSP measurements used in this work were coincident with measurements made by the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS), which was on the same aircraft. These airborne measurements were also coincident with an overpass of the Landsat 8 Operational Land Imager (OLI). First we compare the RSP and OLI radiance measurements to AVIRIS since the spectral response of the multispectral instruments can be used to synthesize a spectrally equivalent signal from the imaging spectrometer data. We then explore a method that uses AVIRIS as a transfer between RSP and OLI to show that radiometric traceability of a satellite-based imager can be used to calibrate a radiometer despite differences in spectral channel sensitivities. This calibration transfer shows agreement within the uncertainty of both the various instruments for most spectral channels.

    关键词： cross calibration,Landsat 8 OLI,radiometric calibration,AVIRIS,RSP

    更新于2025-09-04 15:30:14

  • Product-Specific Nonlinear Characterization and Instrument for Illumination Angle Measurement With Manufacturing Defects

    摘要： Popular sensors that detect the quadrant of the illumination directions are often inadequate for advanced control systems, e.g., solar trackers and heliostats. We propose a theoretical and technical framework for some sensor-specific characterization tools together with an optical instrument, which makes possible the accurate measurements in terms of the illumination angle and its angular velocity at the presence of the manufacturing errors due to rough manufacturing processes (e.g., forging and casting). In particular, a parameter identification approach is employed to identify four uncertain incline angles of sensor products with the aid of an ingenious and controllable calibration device. The angular velocity of illumination is approximately derived through a one-step backward difference function together with finite impulse response filters to reject the disturbances. The experimental results show that the sensor-specific nonlinear characteristic functions improve the accuracy of the illumination angle measurement yielded by the general nonlinear characteristic functions for the ideal sensors up to 96%, where the measurement precision with 0.07° is achieved.

    关键词： parameter estimation,optical sensor,characteristic function,nonlinear optimization,Calibration

    更新于2025-09-04 15:30:14