树莓派4b安装qt5_树莓派4B安装QT与配置OpenCV（最新QT与OpenCV4）
我的环境是官方最新系统即9月份更新的
终端输入：(自动安装最新版本qt)
sudo apt-get update
sudo apt-get install qt5-default qtcreator
配置系统路径
sudo nano /etc/bash.bashrc
在文件的最后添加如下内容
export QTDIR=/opt/Qt5.12.0/5.12.0/gcc_64
export PATH=$QTDIR/bin:$PATH
export LD_LIBRARY_PATH=$QTDIR/lib:$LD_LIBRARY_PATH5_:
然后ctrl+o保存然后ctrl+x退出
source /etc/bash.bashrc
测试配置
echo $PATH
输出如下内容
/opt/Qt5.12.0/5.12.0/gcc_64/bin:/opt/ros/melodic/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin5446722
然后QT就算安装完成
接下来是OpenCV
下载Opencv4.1.0
配置前先下载cmake
sudo apt-get install build-essential
sudo apt-get install cmake git libgtk2.0-dev pkg-config libavcodec-dev libavformat-dev libswscale-dev
sudo apt-get update
sudo apt-get install python-dev python-numpy libtbb2 libtbb-dev libjpeg-dev libpng-dev libtiff-dev libjasper-dev libdc1394-22-dev
QT+Opencv配置：(在opencv文件夹中打开终端)https://docs.opencv.org/4.1.0/d7/d9f/tutorial_linux_install.html
mkdir build
cd build
cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/usr/local ..
make -j4
sudo make install
sudo make
sudo make install
sudo nano /etc/ld.so.conf.d/opencv.conf
加入
/usr/local/lib
然后ctrl+o保存然后ctrl+x退出
sudo ldconfig
接着配置环境变量：
sudo nano /etc/bash.bashrc
写入
PKG_CONFIG_PATH=$PKG_CONFIG_PATH:/usr/local/lib/pkgconfig
export PKG_CONFIG_PATH
然后ctrl+o保存然后ctrl+x退出
sudo ldconfig
终端输入：
sudo cp /usr/local/include/opencv4/opencv2 /usr/local/include -r
到这里为止就完成了，然后测试下：
.pro文件改成下面的内容：
TEMPLATE = app
CONFIG += console c++11
CONFIG -= app_bundle
CONFIG -= qt
SOURCES += main.cpp
INCLUDEPATH += /usr/local/include \
/usr/local/include/opencv
/usr/local/include/opencv2
LIBS += /usr/local/lib/libopencv_calib3d.so.4.1 \
/usr/local/lib/libopencv_core.so.4.1 \
/usr/local/lib/libopencv_features2d.so.4.1 \
/usr/local/lib/libopencv_highgui.so.4.1 \
/usr/local/lib/libopencv_imgcodecs.so.4.1 \
/usr/local/lib/libopencv_imgproc.so.4.1 \
/usr/local/lib/libopencv_ml.so.4.1 \
/usr/local/lib/libopencv_objdetect.so.4.1 \
/usr/local/lib/libopencv_photo.so.4.1 \
/usr/local/lib/libopencv_stitching.so.4.1 \
/usr/local/lib/libopencv_video.so.4.1 \
/usr/local/lib/libopencv_imgcodecs.so.4.1
测试能否调用摄像头：(前提是你有摄像头且配置好了，这个网上很多教程，如果是USB接口的摄像头可能要把VideoCapture capture (0);改成VideoCapture capture (1);或者改成2试试，没有摄像头可以用一张图片试下，就是打开一张图片
下面是.cpp文件内容
#include
#include
#include
#include
using namespace std;
using namespace cv;
int main()
{
VideoCapture capture (0);
Mat src;
while(1)
{
capture >> src;
imshow("11",src);
char(key)=(char)waitKey(1);
if(key==27)
break;
}
return 0;
}