opencv undefined reference to imread with CMake on windows10 VS Code - c++

Question

I want to run OpenCV on VS Code IDE with CMake, but it shows undefined reference to cv::imread(). I've tried several ways (e.g edit PATH variables...) to solve the problem, however it still can link to the opencv library.
Here is my CMakelists.txt
# cmake needs this line
cmake_minimum_required(VERSION 2.8)
# Enable C++11
set(CMAKE_CXX_STANDARD 11)
set(CMAKE_CXX_STANDARD_REQUIRED TRUE)
# Define project name
project(cvtest)
# Find OpenCV, you may need to set OpenCV_DIR variable
# to the absolute path to the directory containing OpenCVConfig.cmake file
# via the command line or GUI
find_package(OpenCV REQUIRED)
set(OpenCV_INCLUDE_DIRS "C:/opencv/build/include")
include_directories(${OpenCV_INCLUDE_DIRS})
# If the package has been found, several variables will
# be set, you can find the full list with descriptions
# in the OpenCVConfig.cmake file.
# Print some message showing some of them
message(STATUS "OpenCV library status:")
message(STATUS " version: ${OpenCV_VERSION}")
message(STATUS " libraries: ${OpenCV_LIBS}")
message(STATUS " include path: ${OpenCV_INCLUDE_DIRS}")
# Declare the executable target built from your sources
add_executable(cvtest cvtest.cpp)
# Link your application with OpenCV libraries
target_link_libraries(cvtest ${OpenCV_LIBS})
After finishing CMake settings, I run $ cmake -G "MinGW Makefiles".
-- OpenCV library status:
-- version: 2.4.13.6
-- libraries: opencv_videostab;opencv_video;opencv_ts;opencv_superres;opencv_stitching;opencv_photo;opencv_ocl;opencv_objdetect;opencv_nonfree;opencv_ml;opencv_legacy;opencv_imgproc;opencv_highgui;opencv_gpu;opencv_flann;opencv_features2d;opencv_core;opencv_contrib;opencv_calib3d
-- include path: C:/opencv/build/include
At last, I run $ mingw32-make, but it came out with some errors
Scanning dependencies of target cvtest
[ 50%] Building CXX object CMakeFiles/cvtest.dir/cvtest.cpp.obj
[100%] Linking CXX executable cvtest.exe
CMakeFiles\cvtest.dir/objects.a(cvtest.cpp.obj):cvtest.cpp:(.text+0x63):
undefined reference to cv::imread(std::string const&, int)'
CMakeFiles\cvtest.dir/objects.a(cvtest.cpp.obj):cvtest.cpp:(.text+0x87):
undefined reference to cv::_InputArray::_InputArray(cv::Mat const&)'
CMakeFiles\cvtest.dir/objects.a(cvtest.cpp.obj):cvtest.cpp:(.text+0xc1):
undefined reference to cv::imshow(std::string const&, cv::_InputArray const&)'
c:/mingw/bin/../lib/gcc/mingw32/4.8.1/../../../../mingw32/bin/ld.exe:
CMakeFiles\cvtest.dir/objects.a(cvtest.cpp.obj): bad reloc address 0xf in section `.text$_ZN2cv3MatD1Ev[__ZN2cv3MatD1Ev]'
c:/mingw/bin/../lib/gcc/mingw32/4.8.1/../../../../mingw32/bin/ld.exe:
final link failed: Invalid operation
collect2.exe: error: ld returned 1 exit status
CMakeFiles\cvtest.dir\build.make:104: recipe for target 'cvtest.exe' failed
mingw32-make[2]: *** [cvtest.exe] Error 1
CMakeFiles\Makefile2:71: recipe for target 'CMakeFiles/cvtest.dir/all' failed
mingw32-make[1]: *** [CMakeFiles/cvtest.dir/all] Error 2
Makefile:82: recipe for target 'all' failed
mingw32-make: *** [all] Error 2
Here is cvtest.cpp
#include <cstdio>
#include <iostream>
#include <opencv2/opencv.hpp>
using namespace cv;
using namespace std;
int main(int argc, char *argv[]) {
Mat img = imread("lena.bmp", CV_LOAD_IMAGE_COLOR);
imshow("lena", img);
}
Did I misunderstanding something I should know and how can I correct it ? Thanks !