Improved Resolution and Reduced Clutter in Ultra-Wideband Microwave Imaging Using Cross-Correlated Back Projection : Experimental and Numerical Results

الملخص EN

Microwave breast cancer detection is based on the dielectric contrast between healthy and malignant tissue.

This radar-based imaging method involves illumination of the breast with an ultra-wideband pulse.

Detection of tumors within the breast is achieved by some selected focusing technique.

Image formation algorithms are tailored to enhance tumor responses and reduce early-time and late-time clutter associated with skin reflections and heterogeneity of breast tissue.

In this contribution, we evaluate the performance of the so-called cross-correlated back projection imaging scheme by using a scanning system in phantom experiments.

Supplementary numerical modeling based on commercial software is also presented.

The phantom is synthetically scanned with a broadband elliptical antenna in a mono-static configuration.

The respective signals are pre-processed by a data-adaptive RLS algorithm in order to remove artifacts caused by antenna reverberations and signal clutter.

Successful detection of a 7 mm diameter cylindrical tumor immersed in a low permittivity medium was achieved in all cases.

Selecting the widely used delay-and-sum (DAS) beamforming algorithm as a benchmark, we show that correlation based imaging methods improve the signal-to-clutter ratio by at least 10 dB and improves spatial resolution through a reduction of the imaged peak full-width half maximum (FWHM) of about 40–50%.