SAIT distance imaging speckle effect suppression method

A technology of synthetic aperture laser and imaging radar, applied in instruments, measuring devices, utilizing re-radiation, etc., can solve the problems affecting SAIL imaging quality, affecting detection signal-to-noise ratio, etc.

Active Publication Date: 2014-07-16
SHANGHAI INST OF OPTICS & FINE MECHANICS CHINESE ACAD OF SCI
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Problems solved by technology

The impact of speckle effect on synthetic aperture laser imaging radar is mainly manifested in affecting the signal-to-noise ratio of optical heterodyne detection and affecting the image quality of SAIL

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  • SAIT distance imaging speckle effect suppression method
  • SAIT distance imaging speckle effect suppression method
  • SAIT distance imaging speckle effect suppression method

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Embodiment Construction

[0025] The present invention will be described in further detail below in conjunction with the accompanying drawings and embodiments, but the protection scope of the present invention should not be limited thereby.

[0026] A method for suppressing speckle effect in range-directed imaging of synthetic aperture laser imaging radar, characterized in that the chirped pulse signal emitted by the laser, that is, the bandwidth of the chirped pulse signal is N (N ≥ 2) times the bandwidth required for the design resolution, and the The echo signal and the local oscillator signal are detected by optical heterodyne, and the obtained data is divided into N parts, which are independently imaged and processed, and the final image output is an incoherent superposition of N images.

[0027] Described chirp signal and optical heterodyne sampling process are as figure 1 shown. The pulse starts from the laser trigger signal t=t0 and lasts until t=t end Cut-off, that is, the pulse width of the...

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Abstract

Provided is an SAIT distance imaging speckle effect suppression method. The bandwidth of linear frequency-modulation pulse signals emitted by a laser device is expanded to N (N is larger than or equal to 2) times of the bandwidth needed by resolution ratio design, and optical heterodyne detection is carried out on echo signals and local oscillator signals to obtain light current data needed for imaging. When data processing is carried out, imaging data obtained after bandwidth expanding are divided into N parts in the distance direction, distance dechirping and orientation focusing imaging are carried out on the data, and ultimately N relatively independent data are produced. Incoherent superposition average is conducted on the N relatively independent target images, and finally images are output. Compared with speckle suppression after uniformization, average strength and contrast of the images are improved to some extent. The method plays a certain role in reducing the speckle effect in an SAIT.

Description

technical field [0001] The invention relates to a synthetic aperture laser imaging radar, which is a method for suppressing the range imaging speckle effect of the synthetic aperture laser imaging radar. Background technique [0002] Synthetic Aperture Lidar Imaging Radar (hereinafter referred to as SAIL) is the application of microwave synthetic aperture radar (hereinafter referred to as SAR) in the optical band. means. SAIL uses near-infrared lasers as radiation sources, and its working wavelength is 3 to 6 orders of magnitude shorter than the radio frequency band of SAR. While achieving higher imaging resolution than SAR, SAIL is also inevitably affected by speckle effects due to the high coherence of laser light. The impact of speckle effect on synthetic aperture lidar is mainly manifested in affecting the signal-to-noise ratio of optical heterodyne detection and affecting the imaging quality of SAIL. [0003] Refer to the following literature: [0004] (1) Robert L....

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01S7/495G01S17/89
CPCG01S7/483G01S17/90
Inventor 许倩孙建锋周煜刘立人孙志伟张宁卢智勇
Owner SHANGHAI INST OF OPTICS & FINE MECHANICS CHINESE ACAD OF SCI
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