由于最近工作需要将实现的图像识别算法，封装到安卓机器上进行测试。因此，初步考虑在公司Windows 7 旗舰版 64位系统中，利用VirtualBox安装Ubuntu系统；然后，在Ubuntu系统中，编译OpenCV和Tesseract-OCR。 具体步骤如下：

一、 安装VirtualBox

• 下载安装VirtualBox
• 安装增强扩展程序VirtualBox 5.1.8 Oracle VM VirtualBox Extension Pack

二、安装Ubuntu

• 下载Ubuntu16.04 64位
• 利用VirtualBox安装Ubuntu16.04

三、编译安装OpenCV

$ sudo apt-get update
$ sudo apt-get upgrade
$ sudo apt-get install build-essential cmake pkg-config
$ sudo apt-get install libjpeg8-dev libtiff5-dev libjasper-dev libpng12-dev
$ sudo apt-get install libavcodec-dev libavformat-dev libswscale-dev libv4l-dev
$ sudo apt-get install libxvidcore-dev libx264-dev
$ sudo apt-get install libgtk-3-dev
$ sudo apt-get install libatlas-base-dev gfortran
$ sudo apt-get install python2.7-dev python3.5-dev

• 下载OpenCV文件

$ cd ~
$ wget -O opencv.zip https://github.com/Itseez/opencv/archive/3.1.0.zip
$ unzip opencv.zip
$ wget -O opencv_contrib.zip https://github.com/Itseez/opencv_contrib/archive/3.1.0.zip
$ unzip opencv_contrib.zip

• 设置Python环境

$ cd ~
$ wget https://bootstrap.pypa.io/get-pip.py
$ sudo python get-pip.py
$ sudo pip install virtualenv virtualenvwrapper
$ sudo rm -rf ~/get-pip.py ~/.cache/pip

修改~/.bashrc

$ echo -e "\n# virtualenv and virtualenvwrapper" >> ~/.bashrc
$ echo "export WORKON_HOME=$HOME/.virtualenvs" >> ~/.bashrc
$ echo "source /usr/local/bin/virtualenvwrapper.sh" >> ~/.bashrc
$ source ~/.bashrc

如果你用python2

$ mkvirtualenv cv -p python2
(cv)$ pip install numpy
(cv)$ cd ~/opencv-3.1.0/
(cv)$ mkdir build
(cv)$ cd build
(cv)$ cmake -D CMAKE_BUILD_TYPE=RELEASE \
    -D CMAKE_INSTALL_PREFIX=/usr/local \
    -D INSTALL_PYTHON_EXAMPLES=ON \
    -D INSTALL_C_EXAMPLES=OFF \
    -D OPENCV_EXTRA_MODULES_PATH=~/opencv_contrib-3.1.0/modules \
    -D PYTHON_EXECUTABLE=~/.virtualenvs/cv/bin/python \
    -D BUILD_EXAMPLES=ON ..

需要的请下载ippicv_linux_20151201.tgz

需要的请下载protobuf-cpp-3.1.0.tar.gz

Make sure Python 2 section includes valid paths to the Interpreter , Libraries , numpy , and packages path.

(cv)$ make -j4 # 4 表示处理器核数目
(cv)$ sudo make install
(cv)$ sudo ldconfig
(cv)$ ls -l /usr/local/lib/python2.7/site-packages/
(cv)$ cd ~/.virtualenvs/cv/lib/python2.7/site-packages/
(cv)$ ln -s /usr/local/lib/python2.7/site-packages/cv2.so cv2.so

如果你用python3

$ mkvirtualenv cv -p python3
(cv) $ pip install numpy
(cv)$ cd ~/opencv-3.1.0/
(cv)$ mkdir build
(cv)$ cd build
(cv)$ cmake -D CMAKE_BUILD_TYPE=RELEASE \
    -D CMAKE_INSTALL_PREFIX=/usr/local \
    -D INSTALL_PYTHON_EXAMPLES=ON \
    -D INSTALL_C_EXAMPLES=OFF \
    -D OPENCV_EXTRA_MODULES_PATH=~/opencv_contrib-3.1.0/modules \
    -D PYTHON_EXECUTABLE=~/.virtualenvs/cv/bin/python \
    -D BUILD_EXAMPLES=ON ..

需要的请下载ippicv_linux_20151201.tgz

需要的请下载protobuf-cpp-3.1.0.tar.gz

Make sure Python 3 section includes valid paths to the Interpreter , Libraries , numpy , and packages path.

(cv)$ make -j4 # 4 表示处理器核数目
(cv)$ sudo make install
(cv)$ sudo ldconfig
(cv)$ ls -l /usr/local/lib/python3.5/site-packages/
(cv)$ cd /usr/local/lib/python3.5/site-packages/
(cv)$ sudo mv cv2.cpython-35m-x86_64-linux-gnu.so cv2.so
(cv)$ cd ~/.virtualenvs/cv/lib/python3.5/site-packages/
(cv)$ ln -s /usr/local/lib/python3.5/site-packages/cv2.so cv2.so

$ cd ~
$ workon cv
(cv)$ python
Python 3.5.2 (default, Jul  5 2016, 12:43:10) 
[GCC 5.4.0 20160609] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import cv2
>>> cv2.__version__
'3.1.0'
>>>

四、安装Tesseract-OCR

$ sudo apt-get update
$ sudo apt-get upgrade
$ sudo apt-get install tesseract-ocr

五、测试OpenCV和Tesseract

• tesscv.cpp

// Using Tesseract API with OpenCV

// Tesseract-OCR
#include <tesseract/baseapi.h>

// C++
#include <iostream>
#include <string>
#include <vector>

// OpenCV
#include "opencv2/core/core.hpp"
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"


int main(int argc, char** argv)
{
    // Usage: tesscv image.png
    if (argc != 2)
    {
        std::cout << "Please specify the input image!" << std::endl;
        return -1;
    }

    // Load image
    cv::Mat im = cv::imread(argv[1], 1);
    if (im.empty())
    {
        std::cout << "Cannot open source image!" << std::endl;
        return -1;
    }

    cv::Mat gray;
    cv::cvtColor(im, gray, CV_BGR2GRAY);
    // ...other image pre-processing here...

    // Pass it to Tesseract API
    tesseract::TessBaseAPI tess;
    tess.Init(NULL, "eng", tesseract::OEM_DEFAULT);
    tess.SetPageSegMode(tesseract::PSM_SINGLE_BLOCK);
    tess.SetImage((uchar*)gray.data, gray.cols, gray.rows, 1, gray.cols);

    // Get the text
    const char* out = tess.GetUTF8Text();
    std::cout << out << std::endl;

    return 0;
}

测试图像

• 编译命令

(cv) tzx@ubuntu:~/Project/test$ g++ -o tesscv tesscv.cpp `pkg-config --cflags --libs opencv tesseract`
(cv) tzx@ubuntu:~/Project/test$ ls
418.jpg  418.txt  tesscv  tesscv.cpp
(cv) tzx@ubuntu:~/Project/test$ ./tesscv 418.jpg 
418


(cv) tzx@ubuntu:~/Project/test$

• g++参数执行顺序的大坑

特别注意g++后面参数的顺序，不然，容易导致未引用的错误。
例如：

(cv) tzx@ubuntu:~/Project/test$ g++ `pkg-config --cflags --libs opencv tesseract` -o tesscv tesscv.cpp 
/tmp/ccTkiDPs.o: In function `main':
tesscv.cpp:(.text+0x91): undefined reference to `cv::imread(cv::String const&, int)'
tesscv.cpp:(.text+0x134): undefined reference to `cv::cvtColor(cv::_InputArray const&, cv::_OutputArray const&, int, int)'
/tmp/ccTkiDPs.o: In function `cv::String::String(char const*)':
tesscv.cpp:(.text._ZN2cv6StringC2EPKc[_ZN2cv6StringC5EPKc]+0x4d): undefined reference to `cv::String::allocate(unsigned long)'
/tmp/ccTkiDPs.o: In function `cv::String::~String()':
tesscv.cpp:(.text._ZN2cv6StringD2Ev[_ZN2cv6StringD5Ev]+0x14): undefined reference to `cv::String::deallocate()'
/tmp/ccTkiDPs.o: In function `cv::Mat::~Mat()':
tesscv.cpp:(.text._ZN2cv3MatD2Ev[_ZN2cv3MatD5Ev]+0x39): undefined reference to `cv::fastFree(void*)'
/tmp/ccTkiDPs.o: In function `cv::Mat::release()':
tesscv.cpp:(.text._ZN2cv3Mat7releaseEv[_ZN2cv3Mat7releaseEv]+0x4b): undefined reference to `cv::Mat::deallocate()'
collect2: error: ld returned 1 exit status

• 问题：

  1. tesseract header not found!

     sudo apt-get install tesseract-ocr-dev

  2. lept.pc not found!

     sudo apt-get install libleptonica-dev

  3. libippicv not found!

  sudo apt-get install libippicv-dev 

  如果，libippicv 还是not found！

  (cv) $ cd /usr/local/include
  (cv) $ sudo mkdir ippicv && cd ippicv
  (cv) $ sudo cp ~/opencv-3.1.0/3rdparty/ippicv/unpack/ippicv_lnx/include/* .
  (cv) $ cd ~
  (cv) $ cd /usr/local/lib
  
  # 如果你用的是64位Ubuntu系统
  
  (cv) $ sudo cp ~/opencv-3.1.0/3rdparty/ippicv/unpack/ippicv_lnx/lib/intel64/libippicv.a .
  
  # 如果你是32位系统Ubuntu系统
  
  (cv) $ sudo cp ~/opencv-3.1.0/3rdparty/ippicv/unpack/ippicv_lnx/lib/ia32/libippicv.a .

参考

Ubuntu 16.04: How to install OpenCV

Done!