opencv(1)qtcreator下环境配置及常见问题

深藏阁楼爱情的钟 2022-06-08 05:15 204阅读 0赞

标签（空格分隔）： opencv

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兜兜转转一年多，一直想学学opencv，无奈大家都是用cmakelist，我虽然也会编写一点，但是嫌太麻烦，每次想要写些简单的例程却想起来自己不会cmake语言，就只好搁浅  
最后发现直接在qtcreator中修改.pro文件一样可行！  
(≧▽≦)/啦啦啦  
好像发现了新世界  
到底是用c++还是python呢，这个问题实在是太纠结了。

## .pro 对项目进行配置 ##

### 1、建立console application ###

### 2、修改.pro文件 ###

之所以想用.pro文件里设置，是因为它直接可以指定要使用的库。我的安装了多个版本的opencv，/usr/include里不知道安装什么的时候安装了opencv2.4.9，但是我需要opencv3.3，每次用cmakelist写的findopencv package 就会自动链接到opencv2.4.9的头文件，即使我设置了OpenCV\_DIR为opencv3.3所在的文件夹，非常乱

INCLUDEPATH += /usr/local/opencv3.3/include \
    /usr/local/opencv3.3/include/opencv \
    /usr/local/opencv3.3/include/opencv2
    
    LIBS += -L/usr/local/opencv3.3/lib \
            -lopencv_core \
            -lopencv_highgui \
            -lopencv_imgcodecs \
            -lopencv_videoio

[参考][Link 1]

### 3.显示图片 ###

修改完配置文件后不要忘记对项目执行qmake！

#include "opencv2/core/core.hpp"
    #include "opencv2/imgcodecs/imgcodecs.hpp"
    #include "opencv2/highgui/highgui.hpp"
    #include "opencv2/videoio/videoio.hpp"
    #include <iostream>
    
    //using namespace cv;
    //using namespace std;
    
    
    
    int main()
    {
    
      cv::Mat image=cv::imread("/home/lgy/workspace/tf/qt/untitled/lgy.jpg");
      cv::namedWindow("lgy");
      cv::imshow("lgy",image);
      cv::waitKey(2000);
    
      return 1;
    }

## CMakelist.txt 进行配置 ##

如下所示，即使我`SET(OpenCV_DIR "/usr/local/opencv3.3/share/OpenCV")` ，还是会发现`#include "opencv2/highgui/highgui.hpp"`的路径是usr/include  
`#include "opencv2/videoio/videoio.hpp"`的路径是/usr/local/opencv3.3，目前还没有找好合适的解决方法

# cmake needs this line
    cmake_minimum_required(VERSION 2.8)
    
    # Define project name
    project(opencv_example_project)
    
    # Find OpenCV, you may need to set OpenCV_DIR variable
    # to the absolute path to the directory containing OpenCVConfig.cmake file
    # via the command line or GUI
    SET(OpenCV_DIR "/usr/local/opencv3.3/share/OpenCV")
    find_package(OpenCV REQUIRED HINTS ${OpenCV_DIR} NO_DEFAULT_PATH )
    
    # If the package has been found, several variables willhighgui
    # be set, you can find the full list with descriptions
    # in the OpenCVConfig.cmake file.
    # Print some message showing some of them
    message(STATUS "OpenCV library status:")
    message(STATUS "    version: ${OpenCV_VERSION}")
    message(STATUS "    libraries: ${OpenCV_LIBS}")
    message(STATUS "    include path: ${OpenCV_INCLUDE_DIRS}")
    
    
    
    # Declare the executable target built from your sources
    add_executable(opencv_example example.cpp)
    
    # Link your application with OpenCV libraries
    target_link_libraries(opencv_example ${OpenCV_LIBS})

## python opencv ##

尝试在conda的虚拟环境pycharm\_tf下使用opencv，结果发现第一个例子就运行不了，没法读取视频文件。  
cv2.VideoCapture失效  
参考[aiz][]的回答，解决方案是用另一个python库skvideo.io来替代cv的这个函数，具体怎么使用这个库函数我还没研究过。以下代码错误

import numpy as np
    import cv2
    import skvideo.io
    
    cap = skvideo.io.VideoCapture('/home/lgy/PycharmProjects/untitled/test.avi')
    
    
    while(1):
        ret, frame = cap.read()
        # gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
    
        cv2.imshow('frame',frame)
        if cv2.waitKey(1) & 0xFF == ord('q'):
            break
    
    cap.release()
    cv2.destroyAllWindows()

用python获取摄像头的视频流倒是可以运行，参考python-opencv 3.0 [tutorial][]中high-gui的使用

这几个例子都比较基础  
相对而言，官方文档给出的[c++的tutorail][c_tutorail] 对我这种基础的小白来说实在是太难消化了，短时间内get不了啊啊啊啊

每个版本的document/mainpage里都有opencv tutorial 和opencv python tutorial

#### 参考 ####

[qt编程指南][qt]

[Link 1]: http://www.cnblogs.com/tornadomeet/archive/2012/07/10/2584702.html
[aiz]: https://github.com/ContinuumIO/anaconda-issues/issues/121
[tutorial]: http://docs.opencv.org/3.0-beta/doc/py_tutorials/py_tutorials.html
[c_tutorail]: http://docs.opencv.org/master/d9/df8/tutorial_root.html
[qt]: https://qtguide.ustclug.org/