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Shu S, Fu Y, Liu S, Zhang Y, Zhang T, Wu T, Gao X. A correction method for radial distortion and nonlinear response of infrared cameras. Rev Sci Instrum 2024; 95:034901. [PMID: 38426900 DOI: 10.1063/5.0187807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 02/06/2024] [Indexed: 03/02/2024]
Abstract
The key feature of non-contact temperature measurement provided by infrared (IR) cameras underpins their versatility. However, the accuracy of temperature measurements with IR cameras depends on imaging quality due to their non-contact nature, such as the lens, body temperature, and measurement environment. This paper addresses the correction of radial distortion and nonlinear response issues in IR cameras. To address radial distortion, we have designed a passive checkerboard calibration board specifically for infrared cameras. This board is used to calibrate the IR camera and derive the necessary camera parameters. Subsequently, these parameters are applied during the actual measurement process to rectify radial distortion effectively. Building on the radial distortion correction method mentioned above, we propose a multi-point segmented calibration approach that considers different temperature ranges and imaging regions. This method alleviates the issue of reduced temperature measurement accuracy due to variations in camera responses by computing gain and offset coefficient matrices for each temperature range. Experimental results demonstrate the effectiveness of the calibration board in correcting radial distortion in IR cameras, with a mean reprojection error of less than 0.16 pixels. Regarding the nonlinear response problem, the introduced method significantly reduces the relative error in temperature measurement. In the verification phase, spanning from 100 to 500 °C, the average relative error in temperature measurement decreases by 0.49% from 1.61% before and after correction, which highlights a substantial improvement in temperature measurement accuracy. This work gives a useful reference to improve the imaging quality and temperature measurement accuracy using infrared cameras.
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Affiliation(s)
- Shuangbao Shu
- Anhui Province Key Laboratory of Measuring Theory and Precision Instrument, School of Instrument Science and Opto-electronics Engineering, Hefei University of Technology, Hefei 230009, China
| | - Yufeng Fu
- Anhui Province Key Laboratory of Measuring Theory and Precision Instrument, School of Instrument Science and Opto-electronics Engineering, Hefei University of Technology, Hefei 230009, China
| | - Shenglin Liu
- Anhui Province Key Laboratory of Measuring Theory and Precision Instrument, School of Instrument Science and Opto-electronics Engineering, Hefei University of Technology, Hefei 230009, China
| | - Yuzhong Zhang
- Anhui Province Key Laboratory of Measuring Theory and Precision Instrument, School of Instrument Science and Opto-electronics Engineering, Hefei University of Technology, Hefei 230009, China
| | - Tengda Zhang
- Anhui Province Key Laboratory of Measuring Theory and Precision Instrument, School of Instrument Science and Opto-electronics Engineering, Hefei University of Technology, Hefei 230009, China
| | - Tianqi Wu
- Anhui Province Key Laboratory of Measuring Theory and Precision Instrument, School of Instrument Science and Opto-electronics Engineering, Hefei University of Technology, Hefei 230009, China
| | - Xinyu Gao
- Anhui Province Key Laboratory of Measuring Theory and Precision Instrument, School of Instrument Science and Opto-electronics Engineering, Hefei University of Technology, Hefei 230009, China
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2
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Logan NC, Hu Q, Paz-Soldan C, Nazikian R, Rhodes T, Wilks T, Munaretto S, Bortolon A, Laggner F, Scotti F, Hong R, Wang H. Improved Particle Confinement with Resonant Magnetic Perturbations in DIII-D Tokamak H-Mode Plasmas. Phys Rev Lett 2022; 129:205001. [PMID: 36461991 DOI: 10.1103/physrevlett.129.205001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 07/22/2022] [Accepted: 10/12/2022] [Indexed: 06/17/2023]
Abstract
Experiments on the DIII-D tokamak have identified a novel regime in which applied resonant magnetic perturbations (RMPs) increase the particle confinement and overall performance. This Letter details a robust range of counter-current rotation over which RMPs cause this density pump-in effect for high confinement (H mode) plasmas. The pump in is shown to be caused by a reduction of the turbulent transport and to be correlated with a change in the sign of the induced neoclassical transport. This novel reversal of the RMP induced transport has the potential to significantly improve reactor relevant, three-dimensional magnetic confinement scenarios.
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Affiliation(s)
- N C Logan
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - Q Hu
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - C Paz-Soldan
- General Atomics, San Diego, California 92186, USA
| | - R Nazikian
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - T Rhodes
- University of California, Los Angeles, Los Angeles, California 90095, USA
| | - T Wilks
- Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - S Munaretto
- General Atomics, San Diego, California 92186, USA
| | - A Bortolon
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - F Laggner
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - F Scotti
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - R Hong
- University of California, Los Angeles, Los Angeles, California 90095, USA
| | - H Wang
- General Atomics, San Diego, California 92186, USA
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3
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Liu L, Yu DL, Shi ZB, Zhai WY, Wu N, Gao JM, Huang ZH, Xia F, He XX, Wei YL, Zhang N, Chen WJ, Yang QW. Visible imaging system with changeable field of view on the HL-2A tokamak. Rev Sci Instrum 2022; 93:083512. [PMID: 36050059 DOI: 10.1063/5.0101643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 07/15/2022] [Indexed: 06/15/2023]
Abstract
A new visible imaging system characterizing a flexible optical design and delivering high resolution frames is established on the HL-2A tokamak. It features a modular configuration, consisting of a front-end imaging lens, a set of bilateral telecentric relay lenses, and a camera. To avoid the effects of plasma radiation (x and gamma-rays) and magnetic field variation on the camera, it should be away from the coils. Therefore, the length of the relay lenses determines the total size of the imaging system. The main feature of this imaging system is to realize the variation of field of view (FOV) by interchanging the front-end prime lenses or by using a zoom lens directly rather than designing the optical system afresh, which lowers the cost drastically. The primary purpose of varying FOV is to enrich the versatility of this system, i.e., focusing on a narrow FOV such as gas puff imaging or a wide FOV such as the plasma cross sections. During the HL-2A experiments, this visible imaging system is used to provide high quality pictures of the plasma-wall interaction, divertor detachment, pellet injections, and so on. The frames confirmed that a strong radiation close to the X point is correlated with the completely detached inner target.
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Affiliation(s)
- L Liu
- Southwestern Institute of Physics, Chengdu 610041, China
| | - D L Yu
- Southwestern Institute of Physics, Chengdu 610041, China
| | - Z B Shi
- Southwestern Institute of Physics, Chengdu 610041, China
| | - W Y Zhai
- Southwestern Institute of Physics, Chengdu 610041, China
| | - N Wu
- Southwestern Institute of Physics, Chengdu 610041, China
| | - J M Gao
- Southwestern Institute of Physics, Chengdu 610041, China
| | - Z H Huang
- Southwestern Institute of Physics, Chengdu 610041, China
| | - F Xia
- Southwestern Institute of Physics, Chengdu 610041, China
| | - X X He
- Southwestern Institute of Physics, Chengdu 610041, China
| | - Y L Wei
- Southwestern Institute of Physics, Chengdu 610041, China
| | - N Zhang
- Southwestern Institute of Physics, Chengdu 610041, China
| | - W J Chen
- Southwestern Institute of Physics, Chengdu 610041, China
| | - Q W Yang
- Southwestern Institute of Physics, Chengdu 610041, China
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Dai LL, Zhu YB, Bai RH, Li Q, Tao RY, Liu LC, Ding JB, Ma F, Zhao X, Cheng SK, Huang XL, Liu MS. Time resolved absolute extreme ultraviolet radiation measurement on the ENN XuanLong-50 spherical tokamak. Rev Sci Instrum 2021; 92:083507. [PMID: 34470401 DOI: 10.1063/5.0040648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 07/26/2021] [Indexed: 06/13/2023]
Abstract
A plasma radiation measurement system for a wide spectral range, based on compact Absolute eXtreme UltraViolet (AXUV) silicon photodiodes, has been implemented on the newly constructed ENN XuanLong-50 (EXL-50) spherical tokamak. The system consists of two 16-channel AXUV16ELG arrays and one AXUV63HS1 single-cell detector mounted on ceramic sockets. The two arrays, facing toward the EXL-50 slim central post from two locations inside a top and a side ConFlat 400 port, have 32 view chords covering the interested plasma region in a poloidal cross section at toroidal 330°. The single-cell detector, seated on a retractable feedthrough, could be arranged flexibly with the help of an ultra-high vacuum compatible gate valve. The design details together with considerations on the EXL-50 specific engineering realities and physics requirements are described. Preliminary results from the EXL-50 2020 experimental campaign are presented.
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Affiliation(s)
- L L Dai
- Hebei Key Laboratory of Compact Fusion, Langfang 065001, China
| | - Y B Zhu
- Hebei Key Laboratory of Compact Fusion, Langfang 065001, China
| | - R H Bai
- Hebei Key Laboratory of Compact Fusion, Langfang 065001, China
| | - Q Li
- Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
| | - R Y Tao
- Hebei Key Laboratory of Compact Fusion, Langfang 065001, China
| | - L C Liu
- Hebei Key Laboratory of Compact Fusion, Langfang 065001, China
| | - J B Ding
- Hebei Key Laboratory of Compact Fusion, Langfang 065001, China
| | - F Ma
- Hebei Key Laboratory of Compact Fusion, Langfang 065001, China
| | - X Zhao
- Hebei Key Laboratory of Compact Fusion, Langfang 065001, China
| | - S K Cheng
- Hebei Key Laboratory of Compact Fusion, Langfang 065001, China
| | - X L Huang
- Hebei Key Laboratory of Compact Fusion, Langfang 065001, China
| | - M S Liu
- Hebei Key Laboratory of Compact Fusion, Langfang 065001, China
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Yang Z, Wang Y, Zhang C, He P, Shu S, Zhang J, Tang B. Techniques Used for Registration and Reconditioning of Infrared Images of the Experimental Advanced Superconducting Tokamak (EAST) Divertor. J Fusion Energ 2020. [DOI: 10.1007/s10894-020-00251-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Chen M, Yang X, Gong X, Gan K, Zhang B, Yang Z. Integrated infrared and visible tangential wide-angle viewing systems for surface temperature measurement and discharge monitoring in EAST. Fusion Engineering and Design 2020. [DOI: 10.1016/j.fusengdes.2019.111415] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Samuell CM, Allen SL, Meyer WH, Isler RC, Briesemeister A, Wilcox RS, Lasnier CJ, Mclean AG, Howard J. Verification of Doppler coherence imaging for 2D ion velocity measurements on DIII-D. Rev Sci Instrum 2018; 89:093502. [PMID: 30278733 DOI: 10.1063/1.5039367] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 08/17/2018] [Indexed: 06/08/2023]
Abstract
Coherence Imaging Spectroscopy (CIS) has emerged as a powerful tool for investigating complex ion phenomena in the boundary of magnetically confined plasma devices. The combination of Fourier-transform interferometry and high-resolution fast-framing cameras has made it possible to make sensitive velocity measurements that are also spatially resolved. However, this sensitivity makes the diagnostic vulnerable to environmental effects including thermal drifts, vibration, and magnetic fields that can influence the velocity measurement. Additionally, the ability to provide an absolute calibration for these geometries can be impacted by differences in the light-collection geometry between the plasma and reference light source, spectral impurities, and the presence of thin-films on in-vessel optics. This paper discusses the mitigation of these effects and demonstration that environmental effects result in less than 0.5 km/s error on the DIII-D CIS systems. A diagnostic comparison is used to demonstrate agreement between CIS and traditional spectroscopy once tomographic artifacts are accounted for.
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Affiliation(s)
- C M Samuell
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - S L Allen
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - W H Meyer
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - R C Isler
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
| | - A Briesemeister
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
| | - R S Wilcox
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
| | - C J Lasnier
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - A G Mclean
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - J Howard
- Australian National University, Canberra, ACT 0200, Australia
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Bortolon A, Maingi R, Mansfield D, Nagy A, Roquemore A, Baylor L, Commaux N, Jackson G, Lunsford R, Lasnier C, Makowski M, Nazikian R, Osborne T, Shiraki D. Mitigation of divertor heat flux by high-frequency ELM pacing with non-fuel pellet injection in DIII-D. Nuclear Materials and Energy 2017. [DOI: 10.1016/j.nme.2017.01.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Granstedt EM, Petrov P, Knapp K, Cordero M, Patel V. Fast imaging diagnostics on the C-2U advanced beam-driven field-reversed configuration device. Rev Sci Instrum 2016; 87:11D416. [PMID: 27910382 DOI: 10.1063/1.4960169] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The C-2U device employed neutral beam injection, end-biasing, and various particle fueling techniques to sustain a Field-Reversed Configuration (FRC) plasma. As part of the diagnostic suite, two fast imaging instruments with radial and nearly axial plasma views were developed using a common camera platform. To achieve the necessary viewing geometry, imaging lenses were mounted behind re-entrant viewports attached to welded bellows. During gettering, the vacuum optics were retracted and isolated behind a gate valve permitting their removal if cleaning was necessary. The axial view incorporated a stainless-steel mirror in a protective cap assembly attached to the vacuum-side of the viewport. For each system, a custom lens-based, high-throughput optical periscope was designed to relay the plasma image about half a meter to a high-speed camera. Each instrument also contained a remote-controlled filter wheel, set between shots to isolate a particular hydrogen or impurity emission line. The design of the camera platform, imaging performance, and sample data for each view is presented.
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Affiliation(s)
- E M Granstedt
- Tri Alpha Energy, P.O. Box 7010, Rancho Santa Margarita, California 92688, USA
| | - P Petrov
- Tri Alpha Energy, P.O. Box 7010, Rancho Santa Margarita, California 92688, USA
| | - K Knapp
- Tri Alpha Energy, P.O. Box 7010, Rancho Santa Margarita, California 92688, USA
| | - M Cordero
- Tri Alpha Energy, P.O. Box 7010, Rancho Santa Margarita, California 92688, USA
| | - V Patel
- Tri Alpha Energy, P.O. Box 7010, Rancho Santa Margarita, California 92688, USA
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Pace D, Van Zeeland M, Fishler B, Murphy C. Consideration of neutral beam prompt loss in the design of a tokamak helicon antenna. Fusion Engineering and Design 2016. [DOI: 10.1016/j.fusengdes.2016.07.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Scotti F, Soukhanovskii VA. A dual wavelength imaging system for plasma-surface interaction studies on the National Spherical Torus Experiment Upgrade. Rev Sci Instrum 2015; 86:123103. [PMID: 26724002 DOI: 10.1063/1.4935609] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A two-channel spectral imaging system based on a charge injection device radiation-hardened intensified camera was built for studies of plasma-surface interactions on divertor plasma facing components in the National Spherical Torus Experiment Upgrade (NSTX-U) tokamak. By means of commercially available mechanically referenced optical components, the two-wavelength setup images the light from the plasma, relayed by a fiber optic bundle, at two different wavelengths side-by-side on the same detector. Remotely controlled filter wheels are used for narrow bandpass and neutral density filters on each optical path allowing for simultaneous imaging of emission at wavelengths differing in brightness up to 3 orders of magnitude. Applications on NSTX-U will include the measurement of impurity influxes in the lower divertor strike point region and the imaging of plasma-material interaction on the head of the surface analysis probe MAPP (Material Analysis and Particle Probe). The diagnostic setup and initial results from its application on the lithium tokamak experiment are presented.
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Affiliation(s)
- F Scotti
- Lawrence Livermore National Laboratory, Livermore, California 94551, USA
| | - V A Soukhanovskii
- Lawrence Livermore National Laboratory, Livermore, California 94551, USA
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