def iou(bbox1, bbox2):
    px1 = bbox1[0]
    py1 = bbox1[1]
    px2 = bbox1[2]
    py2 = bbox1[3]

    gx1 = bbox2[0]
    gy1 = bbox2[1]
    gx2 = bbox2[2]
    gy2 = bbox2[3]

    h = min(py2,gy2) - max(py1,gy1)
    w = min(px2,gx2) - max(px1,gx1)
    w =max(0,w)
    h = max(0,h)
    inter = h*w
    s1 = (px2-px1) * (py2-py1)
    s2 = (gx2-gx1) * (gy2-gy1)
    return inter/(s1+s2-inter)