1. Replace the update source and download source

Using the command lsb_release -a view the current raspberry pie system version. The code of this version is "buster"

pi@raspberrypi:~ $ lsb_release -a
No LSB modules are available.
Distributor ID:	Raspbian
Description:	Raspbian GNU/Linux 10 (buster)
Release:	10
Codename:	buster

Replace mirror source

sudo nano /etc/apt/sources.list

Add a # at the beginning of the first line and copy the following contents to the last line, as shown in the figure:

deb http://mirrors.tuna.tsinghua.edu.cn/raspbian/raspbian/ stretch main contrib non-free rpi
deb-src http://mirrors.tuna.tsinghua.edu.cn/raspbian/raspbian/ stretch main contrib non-free rpi

Check the address of the image source. The version code used is "stretch"

Then change the corresponding "stretch" to "buster"

First press ctrl+o on the keyboard, then press enter to save, and then press ctrl+x to exit the nano editor and return to the command line interface

Then enter the following command to update the latest software list of image source of Tsinghua University

sudo apt-get update

Then restart the raspberry pie

sudo reboot

2. Install numpy

Open the command line interface and enter the following command to install the Python scientific computing library numpy

sudo pip3 install numpy

3. Expand the root directory to the entire SD card in the raspberry pie setting

Enter the command in the command line interface to enter the raspberry pie configuration interface, and use the up and down keys and left and right keys to switch the cursor position

sudo raspi-config

Select Advanced Options

Select expand file system and expand the root directory to the SD card to make full use of the storage space of the SD card. If this step is not carried out, the subsequent commands will be stuck. Exit the setup interface and restart raspberry pie

sudo reboot

4. Install the library required by OpenCV

Run the following eight commands

sudo apt-get install build-essential git cmake pkg-config -y
sudo apt-get install libjpeg8-dev -y
sudo apt-get install libtiff5-dev -y
sudo apt-get install libjasper-dev -y
sudo apt-get install libpng12-dev -y
sudo apt-get install libavcodec-dev libavformat-dev libswscale-dev libv4l-dev -y
sudo apt-get install libgtk2.0-dev -y
sudo apt-get install libatlas-base-dev gfortran -y

5. Download OpenCV

Enter the following three commands on the command line and download two compressed packages to the / home/pi/Downloads directory of raspberry pie. The first compression package is 86.8MB, and the second compression package is 54.5MB:

cd /home/pi/Downloads
wget https://github.com/Itseez/opencv/archive/3.4.0.zip
wget https://github.com/Itseez/opencv_contrib/archive/3.4.0.zip

Unzip the two compressed packages

cd /home/pi/Downloads
unzip opencv-3.4.0.zip
unzip opencv_contrib-3.4.0.zip

6. Set compilation parameters

Set compilation parameters

cd /home/pi/Downloads/opencv-3.4.0
mkdir build
cd build

Set CMAKE parameters

cmake -D CMAKE_BUILD_TYPE=RELEASE -D CMAKE_INSTALL_PREFIX=/usr/local -D INSTALL_C_EXAMPLES=ON -D INSTALL_PYTHON_EXAMPLES=ON -D OPENCV_EXTRA_MODULES_PATH=/home/pi/Downloads/opencv_contrib-3.4.0/modules -D BUILD_EXAMPLES=ON -D WITH_LIBV4L=ON PYTHON3_EXECUTABLE=/usr/bin/python3.5 PYTHON_INCLUDE_DIR=/usr/include/python3.5 PYTHON_LIBRARY=/usr/lib/arm-linux-gnueabihf/libpython3.5m.so PYTHON3_NUMPY_INCLUDE_DIRS=/home/pi/.local/lib/python3.5/site-packages/numpy/core/include ..

Judge whether you have successfully configured CMAKE according to the following figure. If it fails, it may be because the paths of the two compressed packets do not strictly follow the above requirements. If successful, you can start the most important compilation

Failed to configure CMAKE

CMAKE configuration succeeded

7. Compile OpenCV3

Enter the build folder for compilation to prevent ssh disconnection from causing compilation failure. Raspberry pie should ensure sufficient power supply, and it is best not to carry out other operations

cd /home/pi/Downloads/opencv-3.4.0/build
 sudo make -j4 2>&1 | tee make.log

About 18% of the compilation may report fatal error: opencv2 / xfeatures2d / CUDA HPP: there is no such file or directory

This is due to the fact that we installed opencv in Python 2 environment before. We can solve this problem by copying two files: Add / home/pi/Downloads/opencv_contrib-3.4.3/modules/xfeatures2d/include/opencv2 Copy and paste the HPP file into / home/pi/Downloads/opencv-3.4.3/modules/stitching/include/opencv2 directory

When compiling to about 81%, the error build target opencv may be reported_ Tracking [makefile: 163: all] error
This is mainly because the downloaded package is incomplete. Copy the missing files to: home/pi/Downloads/opencv_contrib-3.4.3/modules/xfeatures2d/src/

Missing file download link: https://share.weiyun.com/6gaKPUXf Password: c6myk6

When compiling to about 99%, you may report an error make [2]: * * * [modules / Python 3 / cmakefiles / opencv_python 3. Dir / build. Make: 56: modules / Python 3 / cmakefiles / opencv_python 3. Dir / _ / src2 / CV2. CPP. O] error 1
make[1]: *** [CMakeFiles/Makefile2:21149: modules/python3/CMakeFiles/opencv_python3.dir/all] Error 2
make: *** [Makefile:138: all] Error 2
Find cv2.0 in the path home/pi/Downloads/opencv-3.4.0/modules/python/scr2 CPP this file

texteditor opens and turns to line 885

Add a (char *) before it

Then compile it again. You can pass it after stopping in this place for a long time

8. Install OpenCV3

After compiling, you can proceed to the last step - installation

sudo make install

9. Test OpenCV on Python 3

After installation, enter Python 3 on the command line and press enter

import cv2

enter

cv2.__version__

If the results in the figure below appear, it indicates that OpenCV in Python 3 environment is successfully installed