Using OpenCV on Mac OS X

since: 2013/09/05
update: 2013/12/15
reference:
1. Using OpenCV 2 with OS X – Hello World | Bert Balcaen
2. Homebrew — MacPorts driving you to drink? Try Homebrew!
3. Troubleshooting · mxcl/homebrew Wiki · GitHub

A. 建置環境:
     OS: Mac OS X 10.9
     Xcode: 5.0.2
     OpenCV: 2.4.6

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B. 更新 Java:
     (先安裝 JDK: Java SE Downloads)
     系統偏好設定 > Java > 更新

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C. 更新 / 安裝 Command Line Tools for Xcode:
     Xcode > Preferences... > Downloads > Components >
     Command Line Tools > Install

   如果沒有找到, 就自行下載: (update: 2013/12/15)
    > Downloads for Apple Developers
    > Categories > Developer Tools >
       command_line_tools_os_x_mavericks_for_xcode__late_october_2013.dmg

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D. 安裝 Homebrew package manager:
    打開終端機, 執行以下指令:(一整行)
  //ruby -e "$(curl -fsSL https://raw.github.com/mxcl/homebrew/go)"
    
     (update: 2013/12/15)

       ruby -e "$(curl -fsSL https://raw.github.com/mxcl/homebrew/go/install)"

     > 按 "ENTER" 繼續 ....
   

    > 好了之後, 安裝任何軟體前, 先執行:
       brew doctor
       (說明: brew help)

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E. 安裝 python:
     1. 檢查是否有安裝 python, 如果沒有的話就安裝.
         python -V

     2. 安裝 python: (即使已經有 python 了, 還是建議安裝 homebrew 的 python) 
         brew install python

         (update: 2013/12/15)
         => Setuptools and Pip have been installed. To update them
         pip install --upgrade setuptools
         pip install --upgrade pip
         (update: 2013/12/15)
         => To symlink "Idle" and the "Python Launcher" to ~/Applications
         brew linkapps

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F. 安裝 OpenCV:
     1. 終端機: brew tap homebrew/science

     2. 終端機: brew install opencv

(update: 2013/12/15)
錯誤訊息:
opencv: Unsatisfied dependency: numpy
Brewed Python cannot `import numpy`. Install with:
  pip-2.7 install numpy
Error: An unsatisfied requirement failed this build.

=>  pip-2.7 install numpy
=> brew install opencv

     3. 如果有錯誤訊息的話, 執行: brew doctor
         並參考: Troubleshooting · mxcl/homebrew Wiki · GitHub 的說明.
         (相關指令: brew update, brew doctor, brew --config)
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G. 建立 Xcode 專案:
     1. Xcode > File > New > Project...
         OS X > Application > Command Line Tool

     2. Choose options for your project:
         Product Name: HelloWorld
         Type: C++
          > Next

     3. 幫專案新增一個叫作 OpenCV 的群組: 
         > 並在此群組內, 新增檔案:

         > 先打: / (反斜線), 然後就可以輸入: /usr/local/lib > Go
         > 接著分別選取以下的檔案:
            libopencv_core.dylib
            libopencv_highgui.dylib

         > 並記得勾選: Copy items .... (但原作者說: 不要勾選)
                    及勾選: Add to targets   
         > Add   

        結果如下所示:

         備註: 這是最基本的. 依照使用 OpenCV 不同的功能, 你可能需要其它的檔案.
                   舉例來說, 如果你要作特徵檢測(feature detection), 你會需要:
                    libopencv_features2d.dylib 檔案.

     4. 告訴 Xcode 哪裡可以找到 OpenCV 的標頭檔:
         > 專案 > Build Settings > Search Paths > Header Search Paths :
         > 新增: /usr/local/include

     5. 更改編譯器使用的標準 C++ 函式庫: 
          > 專案 > Build Settings > Apple LLVM compiler 4.2 - Language
          > C++ Standard Library: libstdc++ (GNU C++ standard library)
          (update: 2013/12/15)
          > libc++(LLVM C++ standard library with C++11 support) 預設的

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H. 撰寫 OpenCV 程式:
      1. 開啟 main.cpp 檔案, 修改如下:
#include <iostream>
//@add for OpenCV
#include <opencv2/opencv.hpp>

int main(int argc, const char * argv[])
{

    // insert code here...
    /*
    std::cout << "Hello, World!\n";
    return 0;
    */
   
    //@add for OpenCV
    // load an image
    // make sure you change the path!
    cv::Mat img = cv::imread("/Lanli/RD/Projects/OpenCV_Mac/HelloWorld/pipi.png");
   
    // check if image was loaded
    if (img.data) {
        std::cout << "Image loaded" << std::endl;
    } else {
        std::cout << "Image not loaded" << std::endl;
    }
   
    // create a window and show the image
    cv::imshow("PiPi: a cat", img);
   
    // wait for a key press
    cv::waitKey();
}

      2. 編譯並執行: (按任意鍵結束程式)