4.2 RK3399项目开发实录-案例开发之OpenCV 编译和安装（wulianjishu666）

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3.3. OpenCV 编译和安装

不少客户遇到OpenCV的问题多集中在如何获取mipi摄像头的数据。因为OpenCV使用的V4l2协议和Rockchip编写的mipi摄像头驱动协议不同，所以不能直接使用OpenCV的摄像头API。本节讲述如何编译Opencv并添加GStreamer API支持。

3.3.1. 要求

OS： Ubuntu18.04 / Debian 10
OpenCV version： 3.4.15
Board: RK3399

3.3.2. 编译和安装

搭建python3.7虚拟环境

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# 依次安装gcc和cmake等编译环境
# 安装python3.7-tk 和 python3.7-dev
# 安装virtualenv虚拟环境
sudo apt install gcc cmake git build-essential \
python3-tk python3.7-dev \
virtualenv

创建python3.7虚拟环境

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virtualenv -p /usr/bin/python3.7m /home/firefly/venv
# 使用虚拟环境，如果想退出可以在终端输入 deactivate
source /home/firefly/venv/bin/activate

安装Opencv所需的环境包

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# 安装编译环境、gtk包和相关编解码库
sudo apt install cmake build-essential libgtk2.0-dev pkg-config libavcodec-dev libavformat-dev libswscale-dev libtbb2 libtbb-dev libjpeg-dev libpng-dev libtiff-dev libdc1394-22-dev libjasper-dev

# 注意！如果安装了rknn_toolkit(or lite)则不需要再安装Python-numpy，否则会导致rknn_toolkit(or lite)无法使用
sudo apt install python-numpy

下载Opencv

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# 创建文件夹
mkdir opencv
cd opencv

# 下载 opencv-3.4.15.zip
wget https://github.com/opencv/opencv/archive/refs/tags/3.4.15.zip
unzip opencv-3.4.15.zip

配置

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mkdir build
cd build

# 让 OpenCV 和 Python3 之间建立联系
cmake -D CMAKE_BUILD_TYPE=RELEASE \
-D 	PYTHON_DEFAULT_EXECUTABLE=$(python -c "import sys; print(sys.executable)")\
-D PYTHON3_EXECUTABLE=$(python -c "import sys; print(sys.executable)")  \
-D PYTHON3_NUMPY_INCLUDE_DIRS=$(python -c "import numpy; print (numpy.get_include())")  \
-D PYTHON3_PACKAGES_PATH=$(python -c "from distutils.sysconfig import get_python_lib; print(get_python_lib())")  \
../opencv-3.4.15

如需支持Gstreamer API，则进行以下配置操作否则跳过

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sudo apt install libgstreamer1.0-dev libgstreamer-plugins-base1.0-dev
cmake -D WITH_GSTREAMER=ON ../opencv-3.4.15

编译安装

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# 如果板子内存不超过2G，建议不超过-j4
make -j6
# 安装的过程需要sudo权限
sudo make install

3.3.3. 测试

测试

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source /home/firefly/venv/bin/activate
git clone https://gitlab.com/firefly-linux/test_code/rkisp-v4l2.git
cd mipi_video_demo/OpenCV_Python
python3 opencv_gst_test.py

opencv_gst_test.py 代码

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import numpy as np
import cv2 as cv
import os
import time

cap = cv.VideoCapture('v4l2src device=/dev/video1 ! video/x-raw, format=NV12, width=640, height=480, framerate=30/1 ! videoconvert ! appsink', cv.CAP_GSTREAMER)

if not cap.isOpened():
    print("Cannot capture from camera. Exiting.")
    os._exit()
last_time = time.time()

while(True):

    ret, frame = cap.read()
    this_time = time.time()
    print (str((this_time-last_time)*1000)+'ms')
    last_time = this_time;
    cv.imshow('frame', frame)

    if cv.waitKey(1) & 0xFF == ord('q'):
        break

cap.release()
cv.destroyAllWindows()