install opencv error: ../../lib/libopencv_dnn.so.3.1.0: undefined reference to `google::protobuf:

 Error info:

Linking CXX executable ../../bin/example_dnn_caffe_googlenet

../../lib/libopencv_dnn.so.3.1.0: undefined reference to `google::protobuf::......so on

Solution:

Method 1: reinstall protobuf or upgrade.

  sudo apt-get install --upgrade libprotobuf-dev

 if false,please get into method 2.

Method 2: install protobuf by source,you need choose suitable version 

url https://github.com/google/protobuf/releases

decompression and enter directory

input command:

    ./autogen.sh

    ./configure --prefix=

    make

    sudo make install

Get into your install path

add bin/  /include /lib to environment variables

or copy

    sudo cp bin/protoc /usr/bin

    sudo cp -r include/google /usr/include

    sudo cp -r lib/* /usr/lib