模型是在tensorflow r1.12中訓練的，所以使用tensorflow r1.12的源碼編譯libtensorflow_inference.so來配套移植到Android端，結果報了以下兩個錯誤：
1. Op type not registered 'NonMaxSuppressionV3' in binary running on localhost. Make sure the Op and Kernel are registered in the binary running in this process.
參考：https://www.jianshu.com/p/056ba3cbf02a
2. No OpKernel was registered to support Op 'DenseToDenseSetOperation' with these attrs. Registered devices: [CPU], Registered kernels:
1) 在tensorflow/contrib/makefile/tf_op_files.txt中添加set_kernels.cc
2) 在tensorflow/core/kernels/BUILD中找到：
filegroup(
name = "android_extended_ops_group2",
srcs = [
]
在srcs裏面加上set_kernels.cc
3) 重新編譯libtensorflow_inference.so