先下载编译好的opencv4.5.5的库文件

windows_OpenCV_MinGW_lib_4.5.5.zip-图像处理文档类资源-CSDN下载window10OpenCV4.5.5编译开发库文件，QT可以配置更多下载资源、学习资料请访问CSDN下载频道.https://download.csdn.net/download/rong11417/85692877

​ 最后将install\x64\mingw\bin目录加入环境变量

3 qt配置

INCLUDEPATH += $$PWD/Dev/include

LIBS += -L $$PWD/Dev/x64/mingw/lib/libopencv_*.dll.a

测试程序

.pro文件添加

INCLUDEPATH += $$PWD/Dev/include
LIBS += -L $$PWD/Dev/x64/mingw/lib/libopencv_*.dll.a

#include <iostream>
#include <opencv2/opencv.hpp>
#include <opencv2/core/core.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <QImage>
#include <QPixmap>
#include <QLabel>
#include <QString>
using namespace std;
using namespace cv;



Mat srcImg = imread("D:/test.jpeg");//随便准备一个图片路径，路径不要有中文。
imshow("img",srcImg);//参数一：界面标题，参数二：图片显示对象
cvtColor(srcImg,srcImg,COLOR_BGR2RGB);
Mat fp;
srcImg.convertTo(fp, CV_32F);
QImage disImage2 = QImage((const unsigned char *)(fp.data),fp.cols,fp.rows,QImage::Format_RGB888);
ui->label->setPixmap(QPixmap::fromImage(disImage2.scaled(ui->label->size(),Qt::KeepAspectRatio)));