Algorithm 1. Vessel Shadow Augmentation

1: input: Training image $Xs$

2: hyperparameters: Range of shadow factor S, size of shadow width W″

3: output: Augment image $Xau$

4: Function vessel shadow augmentation $\left(Xs\right)$

5: Shadow width range $\left(W^{″},X{s}_{width}-W^{″}\right)$

6: Shadow height $X{s}_{height}$

7: Shadow mask Shadow width, Shadow height)

8: Shadow mask (Shadow mask × 1/S)

9: $Xs$ × shadow mask

10: end