1、Win7 Qt4.8.5+QtCreator2.8.0+mingw环境参考前博文先搭建
2、下载Cmake2.8.11.2版本，安装。运行
【项目】那编译器选择：MinGW4.4。另外，重新编译OpenCV要使用MinGW4.4编译。 把 “<Qt_directory>mingwin”添加到环境变量PATH中。
在cmd中 gcc -v 看到4.4版本。
3. 编译OpenCV，并测试例子（按照下面例子测试成功）
qt creator2.4.0 + qt4.7.4 + mingw + opencv2.2(win7-32位)配置 http://www.xuebuyuan.com/2162023.html
本实验中2.3.1没有下载成功，所以采用了opencv2.2的版本。
或：OPencv库编译也可参考此文：https://dotuyau.wordpress.com/2014/04/25/opencv_qt_windows/
主要参考下面英文文章：
Steps to build OpenCV 2.3.1 with Qt and MinGW:
1. Install Qt SDK with the C++ compiler option (MinGW). You can download it here.
2. Add “D:QtSDKmingwin” to the system PATH.
3. Download and install CMake (2.8.5).
4. Download and install OpenCV2.3.1 (OpenCV-2.3.1-win-superpack.exe).
5. Run CMake GUI.
6. Set the source code: “D:OpenCV2.3.1_src"
7. Set where to build binaries to: “D:OpenCV2.3.1_out”.
8. Press Configure
9. Let CMake create the new folder.
10. Specify the generator: MinGW Makefiles.
11. Select “Specify Native Compilers” and click Next.
12. For C set: “D:QtSDKmingwingcc.exe”
13. For C++ set: “D:QtSDKmingwing++.exe”
14. Click Finish
15. In the configuration screen type in “DEBUG” (or “RELEASE” if you want to build a release version) for CMAKE_BUILD_TYPE. Check BUILD_EXAMPLES if you want. Check WITH_QT.
16. Click configure again.
17. The configure screen will make you specify the "CUDA_TOOLKIT_ROOT_DIR" path.
set CUDA_TOOLKIT_ROOT_DIR to : "D:/QtSDK/Desktop/Qt/4.7.3/mingw/bin"
18. Click configure again. Click generate. Close CMake.
19. Go to "D:OpenCV2.3.1_out" DIR and type “mingw32-
make” and hit enter (this might take some time).