Mac下使用opencv（2020）

背景

因为工作需求,本人要在MAC端使用OpenCV实现一些视觉功能,配置环境成了最大的阻碍,网上查了很多相关资料和博客,都因为版本环境问题屡试屡败,不过经历重重尝试,笔者最终还是配置成功并运行了自己的源码.当然成功的关键还是因为笔者站在了巨人的肩膀上,借鉴了很多网上的教程

安装opencv

可以通过源码安装，但mac上使用brew安装更加方便

brew search opencv
# 最新版本是opencv4，这里安装openc@2
brew install opencv@2
#安装成功后查看
brew info opencv@2

显示相应信息

opencv@2: stable 2.4.13.7 (bottled) [keg-only]
Open source computer vision library
https://opencv.org/
/usr/local/Cellar/opencv@2/2.4.13.7_11 (278 files, 35.1MB)
  Poured from bottle on 2020-08-14 at 15:44:38
From: https://github.com/Homebrew/homebrew-core/blob/HEAD/Formula/opencv@2.rb
License: BSD-3-Clause
==> Dependencies
Build: cmake ✔, pkg-config ✔
Required: eigen ✔, ffmpeg ✔, jpeg ✔, libpng ✔, libtiff ✔, numpy@1.16 ✔, openexr ✔
==> Requirements
Required: macOS is required ✔
==> Caveats
opencv@2 is keg-only, which means it was not symlinked into /usr/local,
because this is an alternate version of another formula.

If you need to have opencv@2 first in your PATH run:
  echo 'export PATH="/usr/local/opt/opencv@2/bin:$PATH"' >> /Users/tang/.bash_profile

For compilers to find opencv@2 you may need to set:
  export LDFLAGS="-L/usr/local/opt/opencv@2/lib"
  export CPPFLAGS="-I/usr/local/opt/opencv@2/include"

For pkg-config to find opencv@2 you may need to set:
  export PKG_CONFIG_PATH="/usr/local/opt/opencv@2/lib/pkgconfig"

Demo

main.cpp

#include <iostream>
#include <opencv2/opencv.hpp>
using namespace cv;
using std::string;


int main(int argc, const char * argv[]) {
    string path = "/Users/*/Desktop/test.jpg";
    Mat image = imread(path);
    namedWindow("origin");
    imshow("origin", image);
    
    Mat gray;
    cvtColor(image, gray, COLOR_RGBA2GRAY);
    namedWindow("gray");
    imshow("gray", gray);
    waitKey(0);

    return 0;
}

Build

xcode失败

参考了https://www.jianshu.com/p/564c8b352c7f

使用xcode，在Header Search Paths里输入:/usr/local/include 在Library Search Paths里输入:/usr/local/lib

但是build失败。

Build

1	g++ main.cpp

提示

1 2	main.cpp:9:10: fatal error: 'opencv2/opencv.hpp' file not found #include <opencv2/opencv.hpp>

1	g++ -o main main.cpp -L/usr/local/opt/opencv@2/lib -I/usr/local/opt/opencv@2/include

提示

1 2	ld: symbol(s) not found for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation)

pkg-config

后参考https://www.cnblogs.com/zhonghuasong/p/5975975.html

1	g++ $(pkg-config --cflags --libs opencv) main.cpp

任然失败。后来查看brew info opencv@2,提示

1 2	For pkg-config to find opencv@2 you may need to set: export PKG_CONFIG_PATH="/usr/local/opt/opencv@2/lib/pkgconfig"

所以先export

export PKG_CONFIG_PATH="/usr/local/opt/opencv@2/lib/pkgconfig"
#此时 可以查看具体引用库
pkg-config --cflags --libs opencv

# build
g++ $(pkg-config --cflags --libs opencv) main.cpp

这样就成功了。效果如下

Demo2

下面代码可以打开摄像头，读取视频信息。

#include <iostream>
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/opencv.hpp>


using namespace std;
using namespace cv;

IplImage* doCanny(IplImage* image_input,
                  double lowThresh,
                  double highThresh,
                  double aperture)
{
    if(image_input->nChannels != 1)
        return (0);

    IplImage* image_output = cvCreateImage(cvGetSize(image_input),
                                           image_input->depth,
                                           image_input->nChannels);

    cvCanny(image_input,image_output,lowThresh,highThresh,aperture);

    return(image_output);
}


int main(int argc, char* argv[])
{
    cvNamedWindow("Camera" , CV_WINDOW_AUTOSIZE );

    CvCapture* capture = cvCreateCameraCapture(CV_CAP_ANY);

    assert(capture != NULL);

    IplImage *frame = 0;
    frame = cvQueryFrame(capture);

    IplImage *frame_edge = cvCreateImage(cvGetSize(frame),
                                         IPL_DEPTH_8U,
                                         1);
    while(1)
    {
        frame = cvQueryFrame(capture);
        if(!frame) break;

        cvConvertImage(frame,frame_edge,0);
        frame = cvCloneImage(frame_edge);

        frame_edge = doCanny(frame_edge,70,90,3);

        cvShowImage("Camera",frame_edge);
        char c = cvWaitKey(15);
        if(c == 27)  break;
    }

    cvReleaseCapture(&capture);
    cvReleaseImage( &frame_edge );
    cvReleaseImage( &frame);


    return (int)0;
}

参考文章

OpenCV：mac上安装和配置

MAC下配置OpenCV的具体方法(2016年最新)

Mac下用g++编译opencv程序报错