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- 2015
- Calibration process of OSL detectors
- Iodine-131
- OSL-BeO
- Dosimetry of staff and patients
- Optically Stimulated Luminescence (OSL)
- Akdeniz University
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[IEEE 2017 IEEE International Symposium on Medical Measurements and Applications (MeMeA) - Rochester, MN, USA (2017.5.7-2017.5.10)] 2017 IEEE International Symposium on Medical Measurements and Applications (MeMeA) - The calibration of targeting errors for an ultrasound-guided high-intensity focused ultrasound system
摘要： Accurate targeting is one indispensable feature of image-guided high-intensity focused ultrasound (HIFU) systems for treatment safety and efficacy. In our previously developed ultrasound-guided phased-array HIFU system, a rotatable imaging probe was mounted into the central hole of applicator for targeting and monitoring. Two-dimensional image sequence of different imaging planes can be obtained by rotation of the probe. The misalignment between the spots predetermined in the image and the spots sonicated in the tissue can result in the ablation of normal tissue outside the targeting volume, and thus targeting error is unavoidable. An acrylic plate internally placing two flat-head bolts was constructed to measure and calibrate the targeting error. The imaging planes were switched from ?90° to 90° with a 30° step, and the targeting errors were measured 12 times for each of these planes before and after calibration. The targeting errors in other imaging planes could be estimated by linear interpolation using the measured errors in the nearest two imaging planes. The coordinates of the spots to be sonicated were corrected in consideration of the targeting errors in the selected imaging plane. After calibration, the mean targeting errors were reduced to 0.30~0.68 mm from 0.86~1.74 mm. Besides, in the ex vivo experiment the needle-thermocouple tip was used as the target which could be identified in the image. The temperature rise measured by the thermocouple during sonication was in accordance with the theoretical result. In conclusion, the calibration of targeting errors is effective for our system, and the targeting accuracy is also capable to ensure safe sonication.
关键词： Phased-array,Ultrasound-guided high-intensity focused ultrasound (USgHIFU),Targeting accuracy,Calibration
更新于2025-09-04 15:30:14
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Quantitative Determination of Fluorine Content in Blends of Polylactide (PLA)–Talc Using Near Infrared Spectroscopy
摘要： Near-infrared spectroscopy (NIRS) has been widely used for quantitative and/or qualitative determination of a wide range of matrices. The objective of this study was to develop a NIRS method for the quantitative determination of fluorine content in polylactide (PLA)-talc blends. A blending profile was obtained by mixing different amounts of PLA granules and talc powder. The calibration model was built correlating wet chemical data (alkali digestion method) and NIR spectra. Using FT (Fourier Transform)-NIR technique, a Partial Least Squares (PLS) regression model was set-up, in a concentration interval of 0 ppm of pure PLA to 800 ppm of pure talc. Fluorine content prediction (R2 cal = 0.9498; standard error of calibration, SEC = 34.77; standard error of cross-validation, SECV = 46.94) was then externally validated by means of a further 15 independent samples (R2 EX.V = 0.8955; root mean standard error of prediction, RMSEP = 61.08). A positive relationship between an inorganic component as fluorine and NIR signal has been evidenced, and used to obtain quantitative analytical information from the spectra.
关键词： quantitative calibration,fluorine,PLA,polylactide,blends,talc,near infrared spectroscopy
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE 14th International Conference on Automation Science and Engineering (CASE) - Munich, Germany (2018.8.20-2018.8.24)] 2018 IEEE 14th International Conference on Automation Science and Engineering (CASE) - CKF-based Fast Error Compensation Filter Design for IR-UWB Indoor Positioning System for Building Automation
摘要： Recently, impulse radio-ultra wideband is widely used for highly accurate location estimation of robots and objects in indoor space for building automation. For their accurate positioning, calibration must be performed after the positioning system is installed, and a compensation technique of the multipath signals should be performed in real-time. In this paper, a real-time calibration and error compensation method is proposed. A filter that estimates channel common error and channel-specific error sequentially is designed based on cubature Kalman filter and the fast and accurate estimation performance of this filter is verified experimentally.
关键词： indoor positioning,impulse radio-ultra wideband,calibration,cubature Kalman filter,error compensation
更新于2025-09-04 15:30:14
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Fast 3D reconstruction of dental cast model based on structured light
摘要： To quickly obtain accurate 3D data of dental cast model, this paper proposes a 3D reconstruction method for dental cast model based on structured light. This method combines the structured light with the motor turntable to obtain a group of 3D data for the dental cast model from multiple angles, and automatically registers the dental 3D data from multiple angles through the ball calibration of turntable. Compared with the real data of the dental cast model, the maximum error of the 3D reconstruction results in this paper is 0.115 mm. The reconstruction time of this process is about 130 s. The experimental results show that the method has high precision and high scanning speed for the 3D reconstruction of the dental cast model.
关键词： ball calibration,structured light,motor turntable,dental cast model,3D reconstruction
更新于2025-09-04 15:30:14
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Using <sup>220</sup> Rn to calibrate liquid noble gas detectors
摘要： In this paper, we describe 220Rn calibration source that was developed for liquid noble gas detectors. The key advantage of this source is that it can provide 212Bi–212Po consecutive events, which enables us to evaluate the vertex resolution of a detector at low energy by comparing low-energy events of 212Bi and corresponding higher-energy α-rays from 212Po. Since 220Rn is a noble gas, a hot metal getter can be used when introduced using xenon as the carrier gas. In addition, no long-life radioactive isotopes are left behind in the detector after the calibration is complete; this has clear advantage over the use of 222Rn which leaves long-life radioactivity, i.e., 210Pb. Using a small liquid xenon test chamber, we developed a system to introduce 220Rn via the xenon carrier gas; we demonstrated the successful introduction of 6 × 102 220Rn atoms in our test environment.
关键词： calibration,vertex resolution,212Bi–212Po consecutive events,220Rn,liquid noble gas detectors
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE Fourth International Conference on Multimedia Big Data (BigMM) - Xi'an (2018.9.13-2018.9.16)] 2018 IEEE Fourth International Conference on Multimedia Big Data (BigMM) - A Deep-Learning Based Multi-Modality Sensor Calibration Method for USV
摘要： The automatic obstacle avoidance and other tasks of the unmanned surface vehicle rely on the fusion of multi-modality onboard sensors. The accurate calibration method is the foundation of sensor fusion. This paper proposes an online calibration method based on the deep learning for visual sensor and depth sensor. Through an end-to-end network, we combine feature extraction, feature matching and global optimization process of sensor calibration. After initial training, the network can continuously calibrate multi-modality sensors. It solves the challenges under USV operating environment. In the simulation environment and realistic environment, we conducted a fast online calibration of the camera, LIDAR and depth camera, which showed the effectiveness of the algorithm.
关键词： multi-modality sensor,calibration,USV,deep learning
更新于2025-09-04 15:30:14
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Impact of MODIS sensor calibration updates on Greenland Ice Sheet surface reflectance and albedo trends
摘要： We evaluate Greenland Ice Sheet (GrIS) surface re?ectance and albedo trends using the newly released Collection 6 (C6) MODIS (Moderate Resolution Imaging Spectroradiometer) products over the period 2001–2016. We ?nd that the correction of MODIS sensor degradation provided in the new C6 data products reduces the magnitude of the surface re?ectance and albedo decline trends obtained from previous MODIS data (i.e., Collection 5, C5). Collection 5 and 6 data product analysis over GrIS is characterized by surface (i.e., wet vs. dry) and elevation (i.e., 500–2000 m, 2000 m and greater) conditions over the summer season from 1 June to 31 August. Notably, the visible-wavelength declining re?ectance trends identi?ed in several bands of MODIS C5 data from previous studies are only slightly detected at reduced magnitude in the C6 versions over the dry snow area. Declining albedo in the wet snow and ice area remains over the MODIS record in the C6 product, albeit at a lower magnitude than obtained using C5 data. Further analyses of C6 spectral re?ectance trends show both re?ectance increases and decreases in select bands and regions, suggesting that several competing processes are contributing to Greenland Ice Sheet albedo change. Investigators using MODIS data for other ocean, atmosphere and/or land analyses are urged to consider similar re-examinations of trends previously established using C5 data.
关键词： MODIS,sensor calibration,albedo,surface re?ectance,Greenland Ice Sheet
更新于2025-09-04 15:30:14
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New calibration noise suppression techniques for the GLORIA limb imager
摘要： The Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) presents new opportunities for the retrieval of trace gases in the upper troposphere and lower stratosphere. The radiometric calibration of the measured signal is achieved using in-flight measurements of reference blackbody and upward-pointing “deep space” scenes. In this paper, we present techniques developed specifically to calibrate GLORIA data exploiting the instrument’s imaging capability. The algorithms discussed here make use of the spatial correlation of parameters across GLORIA’s detector pixels in order to mitigate the noise levels and artefacts in the calibration measurements. This is achieved by combining a priori and empirical knowledge about the instrument background radiation with noise-mitigating compression methods, specifically low-pass filtering and principal component analysis (PCA). In addition, a new software package for the processing of GLORIA data is introduced which allows us to generate calibrated spectra from raw measurements in a semi-automated data processing chain.
关键词： noise suppression,low-pass filtering,principal component analysis,radiometric calibration,GLORIA
更新于2025-09-04 15:30:14
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Improving the calibration of silicon photodiode pyranometers
摘要： Reliable measurements of global irradiance are essential for research and practical applications. Silicon photodiode pyranometers (SiPs) offer low-cost sensors to measure direct and diffuse irradiance despite their non-uniform spectral response over the 300–1000 nm spectral range. In this study, non-adjusted linear and adjusted calibrations were applied at different times of the year to determine sources of estimated errors in global irradiance due to the two calibration approaches, calibration time, and sensor age. 16 SiPs, along with two standards, measured incident global irradiance over a 5-year period under a range of sky conditions. Sensors performed best in the months in which they were calibrated when using the linear calibration approach. With the solar zenith angle adjusted calibration approach, certain calibration months provide a defendable validation for the following 12 months [ranging an average of 13.5–17.4 W m?2 standard error (SE)], while other calibration months do not provide consistent results and sometimes result in very poor validation (31.1–242.7 W m?2 SE). Older sensors (greater than 6 years) in general become more sensitive to solar zenith angle and their response drifts over time, while newer SiPs performed better than older sensors. Calibrations which accounted for solar zenith angle effects improved global irradiance estimates for older SiPs. For the Lincoln NE location, the appropriate calibration is in spring or late summer, regardless of calibration approach. These results indicate that solar zenith angle correction is not needed for largely diffuse components under cloudy conditions, so that in the future, a “smart” calibration may be possible, where diffuse radiation fractions are known.
关键词： Silicon photodiode pyranometers,Sensor age,Calibration,Solar zenith angle,Global irradiance
更新于2025-09-04 15:30:14
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Visual servoing for low-cost SCARA robots using an RGB-D camera as the only sensor
摘要： Visual servoing with a simple, two-step hand–eye calibration for robot arms in Selective Compliance Assembly Robot Arm configuration, along with the method for simple vision-based grasp planning, is proposed. The proposed approach is designed for low-cost, vision-guided robots, where tool positioning is achieved by visual servoing using marker tracking and depth information provided by an RGB-D camera, without encoders or any other sensors. The calibration is based on identification of the dominant horizontal plane in the camera field of view, and an assumption that all robot axes are perpendicular to the identified plane. Along with the plane parameters, one rotational movement of the shoulder joint provides sufficient information for visual servoing. The grasp planning is based on bounding boxes of simple objects detected in the RGB-D image, which provide sufficient information for robot tool positioning, gripper orientation and opening width. The developed methods are experimentally tested using a real robot arm. The accuracy of the proposed approach is analysed by measuring the positioning accuracy as well as by performing grasping experiments.
关键词： Visual servoing,grasp planning,SCARA,low-cost robot arm,hand–eye calibration
更新于2025-09-04 15:30:14