Calibration of Visibility Samples for Real-Time Passive Millimeter Wave Imaging
A Ka-band 1024-channel passive millimeter wave (PMMW) imager with 1 GHz bandwidth called BHU-1024 has been developed by Beihang University for security screening. BHU-1024 uses linear phased array to obtain resolution in the horizontal direction and uses aperture synthesis to obtain resolution in th...
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doaj-cb78bfac14d64de9916d94f0decc0dfa2021-08-09T23:00:09ZengIEEEIEEE Access2169-35362021-01-01910644110645010.1109/ACCESS.2021.31001029496610Calibration of Visibility Samples for Real-Time Passive Millimeter Wave ImagingYan Zhao0https://orcid.org/0000-0001-5363-0098Anyong Hu1https://orcid.org/0000-0003-0006-7590Weikang Si2Xiangzhou Guo3Jungang Miao4https://orcid.org/0000-0002-8772-7602School of Electronics and Information Engineering, Beihang University, Beijing, ChinaSchool of Electronics and Information Engineering, Beihang University, Beijing, ChinaSchool of Electronics and Information Engineering, Beihang University, Beijing, ChinaSchool of Electronics and Information Engineering, Beihang University, Beijing, ChinaSchool of Electronics and Information Engineering, Beihang University, Beijing, ChinaA Ka-band 1024-channel passive millimeter wave (PMMW) imager with 1 GHz bandwidth called BHU-1024 has been developed by Beihang University for security screening. BHU-1024 uses linear phased array to obtain resolution in the horizontal direction and uses aperture synthesis to obtain resolution in the vertical direction. The non-ideal characteristics of the hardware cause the decrease of system sensitivity and always blur the reconstructed image, hampering applications where high resolution and accurate recognition are emphasized. Hence, effective calibration is a prerequisite to ensure the quality of the millimeter wave image. In this paper, the overall calibration approach is presented, focusing on the main errors relevant to the BHU-1024 instrument design: The basic correlator counts are preprocessed to correct for comparators offset and quadrature error. The residual offset is estimated by continuously sweeping the local oscillator (LO) phase. And for the baseline error, a novel and effective calibration approach, which makes use of an external noise source mounted on the metal frame, is proposed to tackle this problem. The results of simulation and measurement demonstrate the validity of the overall calibration approach. Finally, the actual calibrated data is used to reconstruct the millimeter wave image, which further validates the calibration process.https://ieeexplore.ieee.org/document/9496610/Calibration of visibility sampleshardware imperfectionspassive millimeter wave imagingsecurity screening |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Yan Zhao Anyong Hu Weikang Si Xiangzhou Guo Jungang Miao |
spellingShingle |
Yan Zhao Anyong Hu Weikang Si Xiangzhou Guo Jungang Miao Calibration of Visibility Samples for Real-Time Passive Millimeter Wave Imaging IEEE Access Calibration of visibility samples hardware imperfections passive millimeter wave imaging security screening |
author_facet |
Yan Zhao Anyong Hu Weikang Si Xiangzhou Guo Jungang Miao |
author_sort |
Yan Zhao |
title |
Calibration of Visibility Samples for Real-Time Passive Millimeter Wave Imaging |
title_short |
Calibration of Visibility Samples for Real-Time Passive Millimeter Wave Imaging |
title_full |
Calibration of Visibility Samples for Real-Time Passive Millimeter Wave Imaging |
title_fullStr |
Calibration of Visibility Samples for Real-Time Passive Millimeter Wave Imaging |
title_full_unstemmed |
Calibration of Visibility Samples for Real-Time Passive Millimeter Wave Imaging |
title_sort |
calibration of visibility samples for real-time passive millimeter wave imaging |
publisher |
IEEE |
series |
IEEE Access |
issn |
2169-3536 |
publishDate |
2021-01-01 |
description |
A Ka-band 1024-channel passive millimeter wave (PMMW) imager with 1 GHz bandwidth called BHU-1024 has been developed by Beihang University for security screening. BHU-1024 uses linear phased array to obtain resolution in the horizontal direction and uses aperture synthesis to obtain resolution in the vertical direction. The non-ideal characteristics of the hardware cause the decrease of system sensitivity and always blur the reconstructed image, hampering applications where high resolution and accurate recognition are emphasized. Hence, effective calibration is a prerequisite to ensure the quality of the millimeter wave image. In this paper, the overall calibration approach is presented, focusing on the main errors relevant to the BHU-1024 instrument design: The basic correlator counts are preprocessed to correct for comparators offset and quadrature error. The residual offset is estimated by continuously sweeping the local oscillator (LO) phase. And for the baseline error, a novel and effective calibration approach, which makes use of an external noise source mounted on the metal frame, is proposed to tackle this problem. The results of simulation and measurement demonstrate the validity of the overall calibration approach. Finally, the actual calibrated data is used to reconstruct the millimeter wave image, which further validates the calibration process. |
topic |
Calibration of visibility samples hardware imperfections passive millimeter wave imaging security screening |
url |
https://ieeexplore.ieee.org/document/9496610/ |
work_keys_str_mv |
AT yanzhao calibrationofvisibilitysamplesforrealtimepassivemillimeterwaveimaging AT anyonghu calibrationofvisibilitysamplesforrealtimepassivemillimeterwaveimaging AT weikangsi calibrationofvisibilitysamplesforrealtimepassivemillimeterwaveimaging AT xiangzhouguo calibrationofvisibilitysamplesforrealtimepassivemillimeterwaveimaging AT jungangmiao calibrationofvisibilitysamplesforrealtimepassivemillimeterwaveimaging |
_version_ |
1721213464827920384 |