Figure 1.

The graphical description of different metrics. Box A denotes the ground truth; box B denotes the predicted bounding box. $v=\frac{4}{{\pi }^2}{(arctan\frac{w_A}{h_A}-arctan\frac{w_B}{h_B})}^2$, $\alpha =\frac{v}{(1-IoU)+v}$.