torch.meshgrid()函数解析:https://blog.youkuaiyun.com/weixin_39504171/article/details/106356977
def _create_grid_offsets(size, stride, offset, device):
'''
Argument:
size:turple,value=(h,w),特征图大小
stride:步伐,即原图缩小了stride倍,变成了(h,w)大小
offset:偏移值,BorderDet的offset=0
device:cuda() or cpu
'''
grid_height, grid_width = size
shifts_start