Update edge_detection.py
Update edge_detection.py
HuimingCheng/AutoGrading,HuimingCheng/AutoGrading,Hubert51/AutoGrading,HuimingCheng/AutoGrading,Hubert51/AutoGrading,Hubert51/AutoGrading,Hubert51/AutoGrading,HuimingCheng/AutoGrading,HuimingCheng/AutoGrading,Hubert51/AutoGrading