###### tags: `東京威力 TEL`

# I. 影像辨識 OpenCV
>OpenCV 是拿來處理影響辨識的，用Python環境寫在環境設置上比較方便。
>但考慮算力問題、程式執行效率對影像延遲問題，我先用 C++ 編寫。

:::spoiler
C++和Python實際上在影像延遲的差距仍不確定，待測。
:::

## <font color="orange"> 01. VS Code x Cpp x OpenCV</font>

### <font color="pink">1-1. 安裝 OpenCV</font>

點 [這裡](https://github.com/huihut/OpenCV-MinGW-Build)，下載 `OpenCV-4.5.5-x604`。


下載後將檔案們解壓縮到<font color="yellow">某個自己知道是哪裡</font>的地方。

### <font color="pink">1-2. 安裝 Mingw 64</font>
參考 [之前寫的筆記](https://hackmd.io/@925/By2l-6oU9/%2Fs%2F0kISXK7XQwyYUWtWAKW-9A#-2-2-mingw64-%E5%AE%89%E8%A3%9D) 即可。

### <font color="pink">1-3. 檔案路徑設置</font>
接下來要設定環境變數和 VS Code的 json 檔案，剛下載的資料夾可以放在自己喜歡的地方，但要注意檔案對應的路徑要和下方一樣。

首先，進入「進階系統設定」調整「環境變數」。


接著將下方圖示框起來的兩個資料夾新增到「系統變數」的「Path」中。


:::info
Mingw_openCV是我自己建立的資料夾，檔案具體上要放哪裡依照自己習慣即可，只要注意後續路徑對應的資料夾(也就是剛下載的檔案)是相同的即可。
:::

### <font color="pink">1-4. json 檔案設置</font>

:::warning
注意以下的 json 路徑設置要自行修改成對應的檔案路徑。
:::

在 `.vscode` 資料夾內新增或修改以下幾個檔案 <font color="yellow">（檔名不可修改）</font>，完成後會如下所示：


:::info
開一個獨立的OpenCV資料夾，然後以這個資料夾為工作區打開（如上圖所示）會比較安全。
因為OpenCV要用的編譯和平常的程式檔不一樣，如果不熟悉 .json 檔案的話這樣比較不會弄錯。
:::

`c_cpp_properties.json`

// c_cpp_properties.json
{
  "configurations": [
      {
          "name": "Win32",
          "compilerPath": "C:\\msys64\\mingw64\\bin\\g++.exe",
          "includePath": [
              "${workspaceRoot}",
              "C:\\msys64\\mingw64\\include",                
              "C:\\msys64\\mingw64\\lib\\gcc\\x86_64-w64-mingw32\\11.2.0\\include",
              "C:\\msys64\\mingw64\\include\\c++",
              "D:\\Mingw_openCV\\OpenCV-MinGW-Build-OpenCV-4.5.5-x64\\include"
          ],
          "defines": [
              "_DEBUG",
              "UNICODE",
              "__GNUC__=5",
              "__cdecl=__attribute__((__cdecl__))"
          ],
          "intelliSenseMode": "clang-x64",
          "browse": {
              "path": [
                  "${workspaceRoot}",
                  "C:\\msys64\\mingw64\\include",                
                  "C:\\msys64\\mingw64\\lib\\gcc\\x86_64-w64-mingw32\\11.2.0\\include",
                  "C:\\msys64\\mingw64\\include\\c++"

              ],
              "limitSymbolsToIncludedHeaders": true,
              "databaseFilename": ""
          }
      }
  ],
  "version": 4
}

`launch.json`

// launch.json
{
  "version": "0.2.0",
  "configurations": [
      {
          "name": "(gdb) Launch",
          "type": "cppdbg",
          "request": "launch",
          "program": "${workspaceRoot}/${fileBasenameNoExtension}.exe",
          "args": [],
          "stopAtEntry": false,
          "cwd": "${workspaceRoot}",
          "environment": [],
          "externalConsole": true,
          "MIMode": "gdb",
          "miDebuggerPath": "C:\\msys64\\mingw64\\bin\\gdb.exe",
          "setupCommands": [
              {
                  "description": "Enable pretty-printing for gdb",
                  "text": "-enable-pretty-printing",
                  "ignoreFailures": true
              }
          ],
          "preLaunchTask": "build"
      }
  ]
}

`settings.json`

// settings.json
{
    "files.associations": {
        "array": "cpp",
        "atomic": "cpp",
        "bit": "cpp",
        "*.tcc": "cpp",
        "cctype": "cpp",
        "clocale": "cpp",
        "cmath": "cpp",
        "compare": "cpp",
        "concepts": "cpp",
        "cstdarg": "cpp",
        "cstddef": "cpp",
        "cstdint": "cpp",
        "cstdio": "cpp",
        "cstdlib": "cpp",
        "cwchar": "cpp",
        "cwctype": "cpp",
        "deque": "cpp",
        "string": "cpp",
        "unordered_map": "cpp",
        "vector": "cpp",
        "exception": "cpp",
        "algorithm": "cpp",
        "functional": "cpp",
        "iterator": "cpp",
        "memory": "cpp",
        "memory_resource": "cpp",
        "numeric": "cpp",
        "random": "cpp",
        "string_view": "cpp",
        "system_error": "cpp",
        "tuple": "cpp",
        "type_traits": "cpp",
        "utility": "cpp",
        "initializer_list": "cpp",
        "iosfwd": "cpp",
        "iostream": "cpp",
        "istream": "cpp",
        "limits": "cpp",
        "new": "cpp",
        "numbers": "cpp",
        "ostream": "cpp",
        "stdexcept": "cpp",
        "streambuf": "cpp",
        "typeinfo": "cpp"
    }
}

`tasks.json`

// tasks.json
{
    "version": "2.0.0",
    "tasks": [
        {
            "label": "OpenCV",
            "type": "shell",
            "command": "g++",
            "args": [
                "-g",
                "${file}",
                "-o", 
                "${fileDirname}\\${fileBasenameNoExtension}.exe",                
                "-I", "D:\\Mingw_openCV\\OpenCV-MinGW-Build-OpenCV-4.5.5-x64\\include",
                "-L","D:\\Mingw_openCV\\OpenCV-MinGW-Build-OpenCV-4.5.5-x64\\x64\\mingw\\bin",                
                "-llibopencv_calib3d455",
                "-llibopencv_core455",
                "-llibopencv_dnn455",
                "-llibopencv_features2d455",
                "-llibopencv_flann455",
                "-llibopencv_highgui455",
                "-llibopencv_imgcodecs455",
                "-llibopencv_imgproc455",
                "-llibopencv_ml455",
                "-llibopencv_objdetect455",
                "-llibopencv_photo455",
                "-llibopencv_stitching455",
                "-llibopencv_video455",
                "-llibopencv_videoio455"
            ],
            "group": {
                "kind": "build",
                "isDefault": true
            }
        }
    ]
  }

### <font color="pink">1-5. 初步程式測試</font>

新建一個程式檔 `testing.cpp` 如下：

#include <iostream>
#include <cstdlib>
#include <opencv2/opencv.hpp>

using namespace std;
using namespace cv;

int main(){
    Mat image = imread("smile.jpg"); // smile.jpg 為圖片檔名，名字自取。
    
    while(true){
        imshow("live" , image);
        if(waitKey(0) == 'N') //執行程式後，點一下圖片，再輸入 N 就會結束迴圈。
            break;
    }
    return 0;
}

接著隨便將一張照片放到這個工作區內。
建置檔案一樣 `ctrl+shift+B`：


然後拖曳程式執行檔至 pwsh 內再按 `enter`。


有出現圖片就代表成功建置好環境，沒跑出來可以重開 VS Code 試試看。