Adaptive CLEAN algorithm for millimetre wave synthetic aperture imaging radiometer in near field

High-resolution millimetre wave images of contiguous targets often suffer from the influence of sidelobe artefacts, partial correlation between targets and so on. Owing to the characteristics of near-field synthetic aperture imaging radiometers [such as the changing point spread function (PSF) and slender sideline], the existing CLEAN algorithms are unsuitable for near-field synthetic aperture imaging. This study is devoted to establishing a novel CLEAN algorithm (named adaptive CLEAN) to clean the reconstructed millimetre wave images accurately. First, the characteristics of near-field synthetic aperture imaging are studied. Then, the adaptive CLEAN algorithm is established based on these characteristics. In this study, the authors amend the amplitude of the targets and select the matching PSF for them according to their azimuths. Unlike other CLEAN algorithms, the parameters of this adaptive CLEAN algorithm are calculated by a formula, which is concluded from a lot of simulation experiments. Finally, the effectiveness of the proposed adaptive CLEAN algorithm is tested by several simulation experiments, and the superiority is also demonstrated by comparing it with the existing CLEAN algorithm. The results demonstrate that the proposed method is an efficient, feasible algorithm for cleaning the reconstructed images, irrespective of the point or contiguous targets.

[1]  M. Martín-Neira,et al.  Fringe‐washing function calibration in aperture synthesis microwave radiometry , 2003 .

[2]  B. D. Steinberg,et al.  Reduction of sidelobe and speckle artifacts in microwave imaging: the CLEAN technique , 1988 .

[3]  U. Schwarz.  MATHEMATICAL-STATISTICAL DESCRIPTION OF ITERATIVE BEAM REMOVING TECHNIQUE (METHOD CLEAN) , 1978 .

[4]  L. Yujiri,et al.  Passive Millimeter Wave Imaging , 2003, 2006 IEEE MTT-S International Microwave Symposium Digest.

[5]  Todd Gaier,et al.  Near Field Characterization of the GeoSTAR Demonstrator , 2006, 2006 IEEE International Symposium on Geoscience and Remote Sensing.

[6]  Mabo Robert Ito,et al.  Enhancements to the deconvolution algorithm 'CLEAN' , 1984 .

[7]  Jianfei Chen,et al.  AN ACCURATE IMAGING ALGORITHM FOR MILLIMETER WAVE SYNTHETIC APERTURE IMAGING RADIOMETER IN NEAR-FIELD , 2013 .

[8]  Adriano Camps,et al.  EXTENSION OF THE CLEAN TECHNIQUE TO THE MICROWAVE IMAGING OF CONTINUOUS THERMAL SOURCES BY MEANS OF APERTURE SYNTHESIS RADIOMETERS , 1998 .

[9]  Ranjan Bose.  Lean CLEAN: Deconvolution Algorithm for Radar Imaging of Contiguous Targets , 2011, IEEE Transactions on Aerospace and Electronic Systems.

[10]  Ranjan Bose.  Sequence CLEAN technique using BGA for contiguous radar target images with high sidelobes , 2003 .

[11]  Hai Deng,et al.  Effective CLEAN algorithms for performance-enhanced detection of binary coding radar signals , 2004, IEEE Transactions on Signal Processing.

[12]  J. Högbom,et al.  APERTURE SYNTHESIS WITH A NON-REGULAR DISTRIBUTION OF INTERFEROMETER BASELINES. Commentary , 1974 .

[13]  Li Wu,et al.  Millimetre-wave radiometric imaging for concealed contraband detection on personnel , 2011 .

[14]  R. N. Anderton,et al.  Millimeter-Wave and Submillimeter-Wave Imaging for Security and Surveillance , 2007, Proceedings of the IEEE.

[15]  Ranjan Bose,et al.  Sequence CLEAN: a modified deconvolution technique for microwave images of contiguous targets , 2002 .

[16]  B. G. Clark,et al.  An efficient implementation of the algorithm 'CLEAN' , 1980 .