OpenCV4入门教程004：显示测试

测试

编译完成之后，需要确定编译结果是可以使用的。（安装完成之后也想要测试一下）

最简单的就是写个测试代码验证一下。

本部分代码不需要理解，只需要按照要求可以运行。

为了方便编译运行，我们使用Makefile文件进行快速编译

file = none
CXX = g++
INCPATH = -I. -isystem /usr/include/opencv4
LIBS = -L/usr/lib \
       -lopencv_alphamat -lopencv_aruco -lopencv_bgsegm -lopencv_bioinspired\
       -lopencv_calib3d -lopencv_ccalib -lopencv_core -lopencv_cvv -lopencv_datasets \
       -lopencv_dnn_objdetect -lopencv_dnn_superres -lopencv_dnn -lopencv_dpm \
       -lopencv_face -lopencv_features2d -lopencv_flann -lopencv_freetype -lopencv_fuzzy \
       -lopencv_gapi -lopencv_hdf -lopencv_hfs -lopencv_highgui -lopencv_img_hash -lopencv_imgcodecs\
       -lopencv_imgproc -lopencv_intensity_transform -lopencv_line_descriptor -lopencv_ml \
       -lopencv_objdetect -lopencv_optflow -lopencv_phase_unwrapping -lopencv_photo -lopencv_plot \
       -lopencv_quality -lopencv_rapid -lopencv_reg -lopencv_rgbd -lopencv_saliency -lopencv_shape \
       -lopencv_stitching -lopencv_structured_light -lopencv_superres -lopencv_surface_matching \
       -lopencv_text -lopencv_tracking -lopencv_video -lopencv_videoio -lopencv_videostab -lopencv_viz \
       -lopencv_xfeatures2d -lopencv_ximgproc -lopencv_xobjdetect -lopencv_xphoto 

all:
    $(CXX) -c $(INCPATH) $(file).cpp
    $(CXX) -o $(file) $(file).o $(LIBS)
    rm *.o

将上述文本保存为MakeFile文件，使用时输入make file=filename就可以了。

file可以写死想要编译的文件名，也可以编译时指定。库文件位置根据实际指定。

或者使用CMake

cmake_minimum_required(VERSION 3.10)

project(yolov3)

set(OpenCV_DIR $ENV{OPENCV_PATH})
find_package(OpenCV REQUIRED)
include_directories(${OpenCV_INCLUDE_DIRS})

add_executable(${PROJECT_NAME} "main.cpp")

target_link_libraries(${PROJECT_NAME} ${OpenCV_LIBS})

输出版本号

#include <iostream>
#include <opencv2/opencv.hpp> //头文件
using namespace cv; //包含cv命名空间

int main()
{
    std::cout<<OPENCV_VERSION<<std::endl
    return 0;
}

将以上代码保存为filename.cpp（比如说version.cpp），然后用MakeFile编译

$ make file=version
g++ -c -I. -isystem /usr/include/opencv4 version.cpp
g++ -o version version.o -L/usr/lib -lopencv_core -lopencv_highgui -lopencv_videoio -lopencv_imgcodecs -lopencv_imgproc -lopencv_ml
rm *.o

这里就是编译时指定需要编译的文件名，不需要文件后缀。

执行以后

1 2	`$ ./version 4.2.0`

显示图片

#include <opencv2/opencv.hpp> //头文件
using namespace cv; //包含cv命名空间

int main()
{
    Mat img=imread("./img/1.jpg");// 【1】读入一张图片
    imshow("test",img);// 【2】在窗口中显示载入的图片
    waitKey(6000);// 【3】等待6000ms后窗口自动关闭
}