| Features | Characteristic threshold range |
| Brightness | (110 - 135) |
| Asymmetry | (0.87 - 1) |
| Density | (0.3 - 1.2) |
| Roundness | (1.4 - 3.8) |
| Ellipse fitting | (0 - 0.39) |
| Shape index | (3 - 6.1) |