Proceedings ArticleDOI
Time-frequency transform vs. Fourier transform for radar imaging
V.C. Chen,Shie Qian +1 more
- pp 389-392
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TLDR
By replacing the conventional Fourier transform with the joint time-frequency transform, a 2-D range- doppler Fourier frame becomes a 3-D time-range-Doppler cube and with sampling in time, a sequence of clear 2- D range- Doppler images can be simply reconstructed without using sophisticated motion compensation.Abstract:
Conventional radar imaging systems use the Fourier transform for reconstruction of radar images. To use the Fourier transform adequately, some restrictions must be applied. Due to target's motion and manoeuvring, the reconstructed image by using Fourier transform becomes smeared. Therefore, some sophisticated motion compensation procedures must be applied to produce a clear image. However, the restrictions of Fourier transform can be lifted if a high resolution time-frequency transform can be used to retrieve the Doppler information. By replacing the conventional Fourier transform with the joint time-frequency transform, a 2-D range-Doppler Fourier frame becomes a 3-D time-range-Doppler cube. With sampling in time, a sequence of clear 2-D range-Doppler images can be simply reconstructed without using sophisticated motion compensation.read more
Citations
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Journal ArticleDOI
Joint time-frequency analysis
Shie Qian,Dapang Chen +1 more
TL;DR: This article introduces the so-called model-based (or parametric) time-frequency analysis method, and introduces the basic concepts and well-tested algorithms for joint time- frequencies analysis.
Journal ArticleDOI
Facet Model of Moving Targets for ISAR Imaging and Radar Back-Scattering Simulation
TL;DR: In this article, a facet model of targets is proposed to simulate inverse synthetic aperture radar (ISAR) images and radar back-scattering of moving targets with rigid and nonrigid motions.
Journal ArticleDOI
Range Density Function for Active Sensor Imaging
TL;DR: In this article, a generalised target density function (TDF) is studied for active imaging by sensors such as radar, which is achieved by estimating a new TDF which is called range densityfunction (RDF).
Journal ArticleDOI
ISAR Image Formation Based on Minimum Entropy Criterion and Fractional Fourier Transform
TL;DR: A new JTF-based method is proposed for image formation in inverse synthetic aperture radars (ISAR), which uses minimum entropy criterion for optimum parameter adjustment of JTF algorithms and shows that α-order FrFT with local adjustment has much better performance than the other methods in this category even in low SNR.
Proceedings ArticleDOI
Time-correlation analysis of a class of nonstationary signals with an application to radar imaging
Ta-Hsin Li,Jerry D. Gibson +1 more
TL;DR: A new method of non stationary signal analysis, called time-correlation analysis (TCA), is applied to a class of nonstationary random signals containing time distortion and reveals a relationship between the TCA summary statistics and the distortion and leads to two nonparametric estimators for the distortion function.
References
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Proceedings ArticleDOI
Reconstruction of inverse synthetic aperture radar image using adaptive time-frequency wavelet transform
TL;DR: Adaptive time-frequency wavelet transform is applied to ISAR image reconstruction and a simulation procedure is developed to describe the characteristics of the algorithm.
Journal ArticleDOI
Self-sorting in-place FFT algorithm with minimum working space
Z. Qian,C. Lu,M. An,R. Tolimieri +3 more
TL;DR: This modification of Temperton's (1991) self-sorting, in-place radix-p FFT algorithm reduces the required temporary working space from order of p/sup 2/ to p+1, providing a better match to the limited number of registers in a CPU.
Journal ArticleDOI
Radar ambiguity function, time-varying matched filter, and optimum wavelet correlator
TL;DR: The conventional matched filter can be generalized to a time-varying matched filter, which is equivalent to the optimum time-frequency correlator and can be implemented with wavelet transforms.