Radar-Based Microwave Imaging Sample Clauses

Radar-Based Microwave Imaging. ‌ Microwave radar imaging reconstructs the image using the reflected wave from objects. It uses the reflection that arises due to the difference in the electrical dielectric properties of normal and malignant breast tissues, when microwaves transmit the internal breast with a tumour. This approach, which was first developed as a military ground-penetrating application, is applied to the human body. It was designed in the late 1990s by Xxxxxxx at Wisconsin University, and Xxxxxxxx at Bristol University [62–67]. Researchers at the National University of Ireland, Galway, Tianjin University in China and Hiroshima University are also working on this subject [10, 14, 68–79]. Recently, Goethe University of Frankfurt and the University of Bristol have developed experimental phantom-based imaging on 3D printing technology that was one step closer to the development of standard breast phantoms [80]. Microwave imaging via space–time (MIST) beamforming uses finite impulse response (FIR) filters to compensate for the frequency-dependent time delay, such as dispersion and fractional time delay. The microwave image is formed by summing the filtered signals. Microwave breast cancer imaging uses a generalised likelihood ratio test (GLRT), which is a hypothesis testing problem for each voxel, with the null hypothesis representing the tumour-free case. Reference [68] shows the image formation equations. However, most of those methods have suffered from performance degradation used with dense breast. Thus, at the National University of Ireland, Galway, they used a preprocessing filter to compensate the path-dependent attenuation and phase effects. In addition, they investigated the focal quality metrics to estimate average dielectric properties to enhance tumour detection [81]. The University of Bristol also presented a time-domain wideband adaptive beamforming to reduce clutter [82]. The approach uses an adapted equalisation filter that adapts a calculated estimation of averaging dielectric properties of the breast.