Using opencv in Qt

, ,
1

hi ,
i am using
Qt5.12.11 ,
opencv-4.5.2-vc14_vc15
windows10
I want to write a program to display an image or video from a webcam using Qt and Open CV.
But I was not able to add Open CV to QT. When I used the following link, I encountered these errors in CMake.

https://wiki.qt.io/How_to_setup_Qt_and_openCV_on_Windows

In cmake, I selected the source and destination, but after clicking the configure button, I encountered these errors:

Performing Test HAVE_CXX_WNO_ENUM_COMPARE_SWITCH - Failed
Could NOT find JNI (missing: JAVA_AWT_LIBRARY JAVA_JVM_LIBRARY JAVA_INCLUDE_PATH JAVA_INCLUDE_PATH2 JAVA_AWT_INCLUDE_PATH)
VTK is not found. Please set -DVTK_DIR in CMake to VTK build directory, or to VTK install subdirectory with VTKConfig.cmake file
ADE: Download: v0.1.1f.zip
Try 1 failed
CMake Warning at cmake/OpenCVDownload.cmake:202 (message):
ADE: Download failed: 35;"SSL connect error"

For details please refer to the download log file:

C:/Qt/opencv_cv2/opencv/Release/CMakeDownloadLog.txt

Call Stack (most recent call first):
modules/gapi/cmake/DownloadADE.cmake:5 (ocv_download)
modules/gapi/cmake/init.cmake:19 (include)
cmake/OpenCVModule.cmake:298 (include)
cmake/OpenCVModule.cmake:361 (_add_modules_1)
modules/CMakeLists.txt:7 (ocv_glob_modules)

OpenCV Python: during development append to PYTHONPATH: C:/Qt/opencv_cv2/opencv/Release/python_loader
Could NOT find PkgConfig (missing: PKG_CONFIG_EXECUTABLE)
FFMPEG: Download: opencv_videoio_ffmpeg.dll
Try 1 failed
CMake Warning at cmake/OpenCVDownload.cmake:202 (message):
FFMPEG: Download failed: 35;"SSL connect error"

For details please refer to the download log file:

C:/Qt/opencv_cv2/opencv/Release/CMakeDownloadLog.txt

Call Stack (most recent call first):
3rdparty/ffmpeg/ffmpeg.cmake:20 (ocv_download)
modules/videoio/cmake/detect_ffmpeg.cmake:14 (download_win_ffmpeg)
modules/videoio/cmake/init.cmake:7 (include)
modules/videoio/cmake/init.cmake:18 (add_backend)
cmake/OpenCVModule.cmake:298 (include)
cmake/OpenCVModule.cmake:361 (_add_modules_1)
modules/CMakeLists.txt:7 (ocv_glob_modules)

FFMPEG: Download: opencv_videoio_ffmpeg_64.dll
Try 1 failed
CMake Warning at cmake/OpenCVDownload.cmake:202 (message):
FFMPEG: Download failed: 35;"SSL connect error"

For details please refer to the download log file:

C:/Qt/opencv_cv2/opencv/Release/CMakeDownloadLog.txt

Call Stack (most recent call first):
3rdparty/ffmpeg/ffmpeg.cmake:20 (ocv_download)
modules/videoio/cmake/detect_ffmpeg.cmake:14 (download_win_ffmpeg)
modules/videoio/cmake/init.cmake:7 (include)
modules/videoio/cmake/init.cmake:18 (add_backend)
cmake/OpenCVModule.cmake:298 (include)
cmake/OpenCVModule.cmake:361 (_add_modules_1)
modules/CMakeLists.txt:7 (ocv_glob_modules)

FFMPEG: Download: ffmpeg_version.cmake
Try 1 failed
CMake Warning at cmake/OpenCVDownload.cmake:202 (message):
FFMPEG: Download failed: 35;"SSL connect error"

For details please refer to the download log file:

C:/Qt/opencv_cv2/opencv/Release/CMakeDownloadLog.txt

Call Stack (most recent call first):
3rdparty/ffmpeg/ffmpeg.cmake:20 (ocv_download)
modules/videoio/cmake/detect_ffmpeg.cmake:14 (download_win_ffmpeg)
modules/videoio/cmake/init.cmake:7 (include)
modules/videoio/cmake/init.cmake:18 (add_backend)
cmake/OpenCVModule.cmake:298 (include)
cmake/OpenCVModule.cmake:361 (_add_modules_1)
modules/CMakeLists.txt:7 (ocv_glob_modules)

please help me to solve these errors

2

cmake is trying to download a couple of things, you need a working, SSL enabled internet connection while running it

3

I have faced the similar issue before. It was because of the proxy settings of my company. Furthermore, in your DownloadADE.cmake
MD5 value or download path might not be valid . This thread may help. Try to download ADE source and change the cmake path for this path.

4

thanks alot,
can you tell how can i use this command in windows 10?
~/ADE$ md5sum v0.1.1f.zip

5

i found that command in windows but i have another question,
How to enter the zip file address in Windows?i used this:
“file:C:/Qt/opencv_cv2/ADE/”
but in cmake I encountered this error:
CMake Warning at cmake/OpenCVDownload.cmake:202 (message):
ADE: Download failed: 3;“URL using bad/illegal format or missing URL”