- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Recovering distance information in spectral domain interferometry
摘要： This work evaluates the performance of the Complex Master Slave (CMS) method, that processes the spectra at the interferometer output of a spectral domain interferometry device without involving Fourier transforms (FT) after data acquisition. Reliability and performance of CMS are compared side by side with the conventional method based on FT, phase calibration with dispersion compensation (PCDC). We demonstrate that both methods provide similar results in terms of resolution and sensitivity drop-off. The mathematical operations required to produce CMS results are highly parallelizable, allowing real-time, simultaneous delivery of data from several points of different optical path differences in the interferometer, not possible via PCDC.
关键词： distance measurement,spectral domain interferometry,optical coherence tomography,dispersion compensation,phase calibration,Complex Master Slave,Fourier transforms
更新于2025-09-23 15:23:52
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Development of a Laser Pistonphone System to Calibrate the Sensitivity Modulus and Phase of Microphones for Infrasonic Frequencies
摘要： A laser pistonphone system capable of measuring the sensitivity modulus and phase of microphones is proposed. For the primary vibration calibration, the sine-approximation method has been applied which is used to calculate the complex sensitivity of accelerometers. This method is based on a laser interferometer with quadrature output instead of the fringe-counting method that is used in conventional laser pistonphones. Here, the laser pistonphone system based on the sine-approximation method with the quadrature signal is proposed and the measured results are compared to those obtained by the reciprocity method. The measured sensitivity with the proposed method agrees well with the result of the reciprocity method for the infrasound range. However, in case of the phase sensitivity, the discrepancy is relatively high in comparison to the sensitivity modulus. The results show that the proposed system is capable of calibrating the complex sensitivity of microphones. The improvement of the uncertainty and extension of the frequency range can be achieved by modification of the excitation system for obtaining the required stable excitation with long stroke.
关键词： Infrasound calibration,Infrasound,Phase calibration,Laser pistonphone
更新于2025-09-19 17:13:59
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Polinsar and Tomographic Results Over the Gabonese Forest
摘要： The ESA-sponsored AfriSAR campaign took place in Gabon between 2015 and 2016. It was designed to collect data from tropical forests in order to support the future ESA-BIOMASS mission. This paper addresses the potential of P-band PolIn-SAR and tomography for retrieving vegetation parameters from the multi-baseline airborne data acquired by ONERA over the forest of Lopé. It is shown that a correction of phase disturbances (phase screens) is necessary. A correction procedure based on recent works from the litterature is applied. The PolInSAR and tomographic results are presented and compared with the available LIDAR data.
关键词： SAR Tomography,Phase Calibration,Multi-baseline Synthetic Aperture Radar,PolInSAR
更新于2025-09-10 09:29:36
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Phase Error Compensation in Multi-Baseline SAR Tomography
摘要： This paper explores the main issue surrounding the multi-dimensional synthetic aperture radar (SAR) image focusing techniques, suchlike those caused by the atmosphere propagation delays or by residual platform motion. The problem brings unknown contributions to the phases of complex received signal that it is generally independent of acquisitions track to track and leads spreading and defocusing in multi-dimensional space. To deal with these issues, in this paper an auto-focusing procedure based on sharpness optimization of the reconstructed signal has been employed. The main concern about this technique is that sharpness optimization by itself however can introduce unwanted and uncontrollable vertical shifts in the focused image. To tackle this issue, the phase error is estimated by multiple integration of second derivative of the phase with respect to baseline. The estimation of the calibration phase is performed by optimizing contrast or entropy of the vertical profile with the constraint of a zero phase derivative. In this way, unwanted vertical shifts are avoided and the correct height reference is preserved. Experimental results from the proposed method are evaluated by vertical profile reconstruction performance in the controlled conditions by simulated dataset over the forested area and multi-baseline data acquired by ONERA in Guyana in the frame of European space agency’s campaign TROPISAR.
关键词： synthetic aperture radar (SAR),tomography,Phase calibration,volumetric media
更新于2025-09-09 09:28:46