ENHANCED AND EFFICIENT ISAR IMAGE FOCUSING USING THE DISCRETE GABOR REPRESENTATION IN AN OVERSAMPLING SCHEME

• Published in: Electromagnetic waves (Cambridge, Mass.) Mass.), 2013-06, Vol.138, p.227-244
• Main Authors: Park, Ji-Hoon, Myung, Noh-Hoon
• Format: Article
• Language: English
• Subjects: Algorithms; Image processing; Methods; Properties; Synthetic aperture radar
• ISSN: 1559-8985; 1070-4698; 1559-8985
• DOI: 10.2528/PIER13022004

Inverse synthetic aperture radar (ISAR) imaging is one of the most well-known techniques of radar target recognition. One of the most important issues in ISAR imaging is the improvement of the image smeared by a moving target. In this paper, we propose the discrete Gabor representation (DGR) in an oversampling scheme as an effective means of obtaining a well-focused ISAR image with a short calculation time. In contrast to other linear time-frequency transforms (TFTs), the DGR obtains Gabor coefficients using the analysis window frames derived from the clearly defined Gaussian-type synthesis window. The oversampling scheme of the DGR leads to accurate calculations of the Gabor coefficients, which denote signal time-frequency amplitude. Since each Gabor coefficient is compartmentally assigned to the associated unit cell of the time-frequency grid, the DGR can show an excellent time-frequency concentration and can effectively discriminate the Doppler components of prominent point-scatterers. The application results demonstrate that the DGR not only has enhanced focusing performance but also retains computational efficiency. The DGR in the oversampling scheme is expected to facilitate high-quality ISAR imaging in radar target recognition.