Table 2.
Features extracted from the divided regions
| ID | Reference | Feature description | Category description | Region |
|---|---|---|---|---|
| 1–4 | [26–28] | Area, perimeter, circularity, and shape factor | Mass Shape and margin |
|
| 5–9 | [27–29] | NRL mean, NRL standard deviation, NRL entropy, NCPS, ratio of standard deviation of NRL and average RL |
NRL | |
| 10–12 | [26, 30] | Gradient mean, gradient standard deviation, and gradient skewness | Margin gradient | |
| 13–19 | [26, 30, 31] | Mean of mass, standard deviation of mass, smoothness of mass, skewness of mass, entropy of mass, uniformity of mass, and kurtosis of mass |
Gray-level histogram | |
| 20–21 | [30] | Fluctuation mean of ROI and fluctuation standard deviation of ROI | Pixel value fluctuation | ROI |
| 22–28 | [26, 28, 30] | Mean of background, standard deviation of background, smoothness of background, skewness of background, entropy of background, uniformity of background and kurtosis of background |
Gray-level histogram | Background |
| 29–32 | [30, 32] | Fluctuation mean of background, region conspicuity, fluctuation standard deviation of background and average gray value difference of mass and background |
Pixel value fluctuation |
NRL normalized radial length, NCPS normalized central position shift, RL radial length, ROI region of interest