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Proceedings Paper

Image processing algorithm of equiarm delay line in SAIL
Author(s): Nan Xu; Liren Liu; Wei Lu
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Paper Abstract

The phase errors due to the nonlinear chirp of a tunable laser reduce the range resolution in Synthetic Aperture Imaging Ladar (SAIL). The analogue and digital image processing algorithms were developed, and all the image processing algorithms employed matched or nonmatched optical delay line. In this paper a theory of equiarm delay line to compensate the nonlinear chirp phase errors is proposed. This image processing algorithm includes three methods with different compensation precision and implementation difficulties, and promotes the application flexibility. Firstly, we derive the theory that the impact of the nonlinear chirp is suppressed with decreasing the delay time difference of the echo signal and the LO signal. Based on the theory, we propose three methods to establish the equiarm delay line: establishing matched target LO path, establishing reference path and dual coherent detections, establishing reference path and phase shifting calculation. Then the construction of the signal processing system and the mathematical flow of the algorithm are established. The simulations of the airborne synthetic aperture imaging ladar model approve that three methods suppress the phase errors of the nonlinear chirp to various extent, and improve the range resolution. The characteristics and the applicabilities of three methods are discussed finally.

Paper Details

Date Published: 8 September 2010
PDF: 7 pages
Proc. SPIE 7797, Optics and Photonics for Information Processing IV, 779710 (8 September 2010); doi: 10.1117/12.859791
Show Author Affiliations
Nan Xu, Shanghai Institute of Optics and Fine Mechanics (China)
Liren Liu, Shanghai Institute of Optics and Fine Mechanics (China)
Wei Lu, Shanghai Institute of Optics and Fine Mechanics (China)


Published in SPIE Proceedings Vol. 7797:
Optics and Photonics for Information Processing IV
Abdul Ahad Sami Awwal; Khan M. Iftekharuddin; Scott C. Burkhart, Editor(s)

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