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. Author manuscript; available in PMC: 2020 Apr 13.
Published in final edited form as: Med Phys. 2018 Feb 19;45(3):1178–1190. doi: 10.1002/mp.12763

Figure 2.

Figure 2.

This figure shows a few examples from each density level and mammographic view on how we established the ground truth mask for dense fibroglandular area. Images on the left side of the panel show the original mammograms. Images in the middle show the results after applying manually delineated breast area mask and skin removal using a binary image erosion technique. Then, we applied a thresholding method to get ground truth mask for dense fibroglandular area. We used the mid-point of quartiles, i.e., 12.5, 37.5, 62.5, and 87.5 percentiles, of pixel intensity distribution as thresholds. Then, we assigned any pixels higher than a given threshold as dense fibroglandular area. Note that we selected thresholds in descending order based on each case’s BI-RADS density level. For example, we selected the 87.5 percentile as the threshold for BI-RADS density level 1 cases. Images on the right side of the panel show the results after applying the thresholding method. Also shown are the pixel intensity histograms inside the breast area.