Fig. 2
From: Breast density classification using frequency-based features in microwave imaging
Average spatial patterns (magnitude) at selected frequencies. Each plot shows the mean magnitude of S21 across receiver positions for a fixed frequency (2, 4, 6, 8 GHz), averaged across multiple representative breasts in each density class (LD, HD). Averages are shown to emphasise typical class behaviour (individual breasts vary). The spatial traces illustrate that HD breasts tend to display richer oscillatory structure across receiver angle whereas LD breasts appear smoother in the averaged response. This difference is confirmed through a quantitative analysis of standard deviation and the coefficient of variation.
