A High-Frequency Vibration Error Compensation Method for Terahertz SAR Imaging Based on Short-Time Fourier Transform
High-frequency vibration error of a moving radar platform easily introduces a non-negligible phase of periodic modulation in radar echoes and greatly degrades terahertz synthetic aperture radar (THz-SAR) image quality. For solving the problem of THz-SAR image-quality degradation, the paper proposes...
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MDPI AG
2021-11-01
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| Series: | Applied Sciences |
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| Online Access: | https://www.mdpi.com/2076-3417/11/22/10862 |
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| author | Yinwei Li Qi Wu Jiawei Jiang Xia Ding Qibin Zheng Yiming Zhu |
| author_facet | Yinwei Li Qi Wu Jiawei Jiang Xia Ding Qibin Zheng Yiming Zhu |
| author_sort | Yinwei Li |
| collection | DOAJ |
| description | High-frequency vibration error of a moving radar platform easily introduces a non-negligible phase of periodic modulation in radar echoes and greatly degrades terahertz synthetic aperture radar (THz-SAR) image quality. For solving the problem of THz-SAR image-quality degradation, the paper proposes a multi-component high-frequency vibration error estimation and compensation approach based on the short-time Fourier transform (STFT). To improve the robustness of the method against noise effects, STFT is used to extract the instantaneous frequency (IF) of a high-frequency vibration error signal, and the vibration parameters are coarsely obtained by the least square (LS) method. To reduce the influence of the STFT window widths, a method based on the maximum likelihood function (MLF) is developed for determining the optimal window width by a one-dimensional search of the window widths. In the case of high noise, many IF estimation values seriously deviate from the true ones. To avoid the singular values of IF estimation in the LS regression, the random sample consensus (RANSAC) is introduced to improve estimation accuracy. Then, performing the STFT with the optimal window width, the accurate vibration parameters are estimated by LS regression, where the singular values of IF estimation are excluded. Finally, the vibration error is reconstructed to compensate for the non-negligible phase of the platform-induced periodic modulation. The simulation results prove that the error compensation method can meet THz-SAR imaging requirements, even at a low signal-to-noise ratio (SNR). |
| first_indexed | 2024-03-10T05:43:04Z |
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| id | doaj.art-38900a5c84504c37864976b60a8750ec |
| institution | Directory Open Access Journal |
| issn | 2076-3417 |
| language | English |
| last_indexed | 2024-03-10T05:43:04Z |
| publishDate | 2021-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Applied Sciences |
| spelling | doaj.art-38900a5c84504c37864976b60a8750ec2023-11-22T22:20:03ZengMDPI AGApplied Sciences2076-34172021-11-0111221086210.3390/app112210862A High-Frequency Vibration Error Compensation Method for Terahertz SAR Imaging Based on Short-Time Fourier TransformYinwei Li0Qi Wu1Jiawei Jiang2Xia Ding3Qibin Zheng4Yiming Zhu5Terahertz Technology Innovation Research Institute, Terahertz Spectrum and Imaging Technology Cooperative Innovation Center, Shanghai Key Lab of Modern Optical System, University of Shanghai for Science and Technology, Shanghai 200093, ChinaSchool of Optoelectronic Information and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, ChinaSchool of Optoelectronic Information and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, ChinaShanghai Radio Equipment Research Institute, Shanghai 201109, ChinaTerahertz Technology Innovation Research Institute, Terahertz Spectrum and Imaging Technology Cooperative Innovation Center, Shanghai Key Lab of Modern Optical System, University of Shanghai for Science and Technology, Shanghai 200093, ChinaTerahertz Technology Innovation Research Institute, Terahertz Spectrum and Imaging Technology Cooperative Innovation Center, Shanghai Key Lab of Modern Optical System, University of Shanghai for Science and Technology, Shanghai 200093, ChinaHigh-frequency vibration error of a moving radar platform easily introduces a non-negligible phase of periodic modulation in radar echoes and greatly degrades terahertz synthetic aperture radar (THz-SAR) image quality. For solving the problem of THz-SAR image-quality degradation, the paper proposes a multi-component high-frequency vibration error estimation and compensation approach based on the short-time Fourier transform (STFT). To improve the robustness of the method against noise effects, STFT is used to extract the instantaneous frequency (IF) of a high-frequency vibration error signal, and the vibration parameters are coarsely obtained by the least square (LS) method. To reduce the influence of the STFT window widths, a method based on the maximum likelihood function (MLF) is developed for determining the optimal window width by a one-dimensional search of the window widths. In the case of high noise, many IF estimation values seriously deviate from the true ones. To avoid the singular values of IF estimation in the LS regression, the random sample consensus (RANSAC) is introduced to improve estimation accuracy. Then, performing the STFT with the optimal window width, the accurate vibration parameters are estimated by LS regression, where the singular values of IF estimation are excluded. Finally, the vibration error is reconstructed to compensate for the non-negligible phase of the platform-induced periodic modulation. The simulation results prove that the error compensation method can meet THz-SAR imaging requirements, even at a low signal-to-noise ratio (SNR).https://www.mdpi.com/2076-3417/11/22/10862high-frequency vibration errormaximum likelihood function (MLF)short-time Fourier transform (STFT)random sample consensus (RANSAC)terahertz synthetic aperture radar (THz-SAR) |
| spellingShingle | Yinwei Li Qi Wu Jiawei Jiang Xia Ding Qibin Zheng Yiming Zhu A High-Frequency Vibration Error Compensation Method for Terahertz SAR Imaging Based on Short-Time Fourier Transform Applied Sciences high-frequency vibration error maximum likelihood function (MLF) short-time Fourier transform (STFT) random sample consensus (RANSAC) terahertz synthetic aperture radar (THz-SAR) |
| title | A High-Frequency Vibration Error Compensation Method for Terahertz SAR Imaging Based on Short-Time Fourier Transform |
| title_full | A High-Frequency Vibration Error Compensation Method for Terahertz SAR Imaging Based on Short-Time Fourier Transform |
| title_fullStr | A High-Frequency Vibration Error Compensation Method for Terahertz SAR Imaging Based on Short-Time Fourier Transform |
| title_full_unstemmed | A High-Frequency Vibration Error Compensation Method for Terahertz SAR Imaging Based on Short-Time Fourier Transform |
| title_short | A High-Frequency Vibration Error Compensation Method for Terahertz SAR Imaging Based on Short-Time Fourier Transform |
| title_sort | high frequency vibration error compensation method for terahertz sar imaging based on short time fourier transform |
| topic | high-frequency vibration error maximum likelihood function (MLF) short-time Fourier transform (STFT) random sample consensus (RANSAC) terahertz synthetic aperture radar (THz-SAR) |
| url | https://www.mdpi.com/2076-3417/11/22/10862 |
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