I need OpenCV3.0 since it supports some new functions which I need. I used the following code for installation (I had successfully installed OpenCV 2.4.9 using this code. But for OpenCV 3.0, while doing the cmake section, some error pops up due to mismatch of MD5 checksum)

mkdir OpenCV
cd OpenCV
echo "Removing any pre-installed ffmpeg and x264"
sudo apt-get -qq remove ffmpeg x264 libx264-dev
echo "Installing Dependenices"
sudo apt-get -qq install libopencv-dev build-essential checkinstall cmake pkg-config yasm libjpeg-dev libjasper-dev libavcodec-dev libavformat-dev libswscale-dev libdc1394-22-dev libxine-dev libgstreamer0.10-dev libgstreamer-plugins-base0.10-dev libv4l-dev python-dev python-numpy libtbb-dev libqt4-dev libgtk2.0-dev libfaac-dev libmp3lame-dev libopencore-amrnb-dev libopencore-amrwb-dev libtheora-dev libvorbis-dev libxvidcore-dev x264 v4l-utils ffmpeg
echo "Installing OpenCV" $version
unzip OpenCV-3.0.zip #i manually installed opencv3.0 zipfile for linux from https://github.com/Itseez/opencv/archive/3.0.0-alpha.zip
cd opencv-3.0.0-alpha
mkdir build
cd build
cmake -D CMAKE_BUILD_TYPE=RELEASE -D CMAKE_INSTALL_PREFIX=/usr/local -D WITH_TBB=ON -D BUILD_NEW_PYTHON_SUPPORT=ON -D WITH_V4L=ON -D INSTALL_C_EXAMPLES=ON -D INSTALL_PYTHON_EXAMPLES=ON -D BUILD_EXAMPLES=ON -D WITH_QT=ON -D WITH_OPENGL=ON ..
make -j2
sudo checkinstall
sudo sh -c 'echo "/usr/local/lib" > /etc/ld.so.conf.d/opencv.conf'
sudo ldconfig
echo "OpenCV 3.0 ready to be used"
 

When I execute the cmake command, I encounter errors. The output is shown below:

[email protected]:~/OpenCV/opencv-3.0.0-alpha/build$ cmake -D WITH_TBB=ON -D BUILD_NEW_PYTHON_SUPPORT=ON -D WITH_V4L=ON -D INSTALL_C_EXAMPLES=ON -D INSTALL_PYTHON_EXAMPLES=ON -D BUILD_EXAMPLES=ON -D WITH_QT=ON -D WITH_OPENGL=ON ..
-- The CXX compiler identification is GNU
-- The C compiler identification is GNU
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working C compiler: /usr/bin/gcc
-- Check for working C compiler: /usr/bin/gcc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detected version of GNU GCC: 46 (406)
-- Performing Test HAVE_CXX_FSIGNED_CHAR
-- Performing Test HAVE_CXX_FSIGNED_CHAR - Success
-- Performing Test HAVE_C_FSIGNED_CHAR
-- Performing Test HAVE_C_FSIGNED_CHAR - Success
-- Performing Test HAVE_CXX_W
-- Performing Test HAVE_CXX_W - Success
-- Performing Test HAVE_C_W
-- Performing Test HAVE_C_W - Success
-- Performing Test HAVE_CXX_WALL
-- Performing Test HAVE_CXX_WALL - Success
-- Performing Test HAVE_C_WALL
-- Performing Test HAVE_C_WALL - Success
-- Performing Test HAVE_CXX_WERROR_RETURN_TYPE
-- Performing Test HAVE_CXX_WERROR_RETURN_TYPE - Success
-- Performing Test HAVE_C_WERROR_RETURN_TYPE
-- Performing Test HAVE_C_WERROR_RETURN_TYPE - Success
-- Performing Test HAVE_CXX_WERROR_NON_VIRTUAL_DTOR
-- Performing Test HAVE_CXX_WERROR_NON_VIRTUAL_DTOR - Success
-- Performing Test HAVE_C_WERROR_NON_VIRTUAL_DTOR
-- Performing Test HAVE_C_WERROR_NON_VIRTUAL_DTOR - Success
-- Performing Test HAVE_CXX_WERROR_ADDRESS
-- Performing Test HAVE_CXX_WERROR_ADDRESS - Success
-- Performing Test HAVE_C_WERROR_ADDRESS
-- Performing Test HAVE_C_WERROR_ADDRESS - Success
-- Performing Test HAVE_CXX_WERROR_SEQUENCE_POINT
-- Performing Test HAVE_CXX_WERROR_SEQUENCE_POINT - Success
-- Performing Test HAVE_C_WERROR_SEQUENCE_POINT
-- Performing Test HAVE_C_WERROR_SEQUENCE_POINT - Success
-- Performing Test HAVE_CXX_WFORMAT
-- Performing Test HAVE_CXX_WFORMAT - Success
-- Performing Test HAVE_C_WFORMAT
-- Performing Test HAVE_C_WFORMAT - Success
-- Performing Test HAVE_CXX_WERROR_FORMAT_SECURITY
-- Performing Test HAVE_CXX_WERROR_FORMAT_SECURITY - Success
-- Performing Test HAVE_C_WERROR_FORMAT_SECURITY
-- Performing Test HAVE_C_WERROR_FORMAT_SECURITY - Success
-- Performing Test HAVE_CXX_WMISSING_DECLARATIONS
-- Performing Test HAVE_CXX_WMISSING_DECLARATIONS - Success
-- Performing Test HAVE_C_WMISSING_DECLARATIONS
-- Performing Test HAVE_C_WMISSING_DECLARATIONS - Success
-- Performing Test HAVE_CXX_WMISSING_PROTOTYPES
-- Performing Test HAVE_CXX_WMISSING_PROTOTYPES - Failed
-- Performing Test HAVE_C_WMISSING_PROTOTYPES
-- Performing Test HAVE_C_WMISSING_PROTOTYPES - Success
-- Performing Test HAVE_CXX_WSTRICT_PROTOTYPES
-- Performing Test HAVE_CXX_WSTRICT_PROTOTYPES - Failed
-- Performing Test HAVE_C_WSTRICT_PROTOTYPES
-- Performing Test HAVE_C_WSTRICT_PROTOTYPES - Success
-- Performing Test HAVE_CXX_WUNDEF
-- Performing Test HAVE_CXX_WUNDEF - Success
-- Performing Test HAVE_C_WUNDEF
-- Performing Test HAVE_C_WUNDEF - Success
-- Performing Test HAVE_CXX_WINIT_SELF
-- Performing Test HAVE_CXX_WINIT_SELF - Success
-- Performing Test HAVE_C_WINIT_SELF
-- Performing Test HAVE_C_WINIT_SELF - Success
-- Performing Test HAVE_CXX_WPOINTER_ARITH
-- Performing Test HAVE_CXX_WPOINTER_ARITH - Success
-- Performing Test HAVE_C_WPOINTER_ARITH
-- Performing Test HAVE_C_WPOINTER_ARITH - Success
-- Performing Test HAVE_CXX_WSHADOW
-- Performing Test HAVE_CXX_WSHADOW - Success
-- Performing Test HAVE_C_WSHADOW
-- Performing Test HAVE_C_WSHADOW - Success
-- Performing Test HAVE_CXX_WSIGN_PROMO
-- Performing Test HAVE_CXX_WSIGN_PROMO - Success
-- Performing Test HAVE_C_WSIGN_PROMO
-- Performing Test HAVE_C_WSIGN_PROMO - Failed
-- Performing Test HAVE_CXX_WNO_NARROWING
-- Performing Test HAVE_CXX_WNO_NARROWING - Failed
-- Performing Test HAVE_C_WNO_NARROWING
-- Performing Test HAVE_C_WNO_NARROWING - Failed
-- Performing Test HAVE_CXX_WNO_DELETE_NON_VIRTUAL_DTOR
-- Performing Test HAVE_CXX_WNO_DELETE_NON_VIRTUAL_DTOR - Failed
-- Performing Test HAVE_C_WNO_DELETE_NON_VIRTUAL_DTOR
-- Performing Test HAVE_C_WNO_DELETE_NON_VIRTUAL_DTOR - Failed
-- Performing Test HAVE_CXX_WNO_UNNAMED_TYPE_TEMPLATE_ARGS
-- Performing Test HAVE_CXX_WNO_UNNAMED_TYPE_TEMPLATE_ARGS - Failed
-- Performing Test HAVE_C_WNO_UNNAMED_TYPE_TEMPLATE_ARGS
-- Performing Test HAVE_C_WNO_UNNAMED_TYPE_TEMPLATE_ARGS - Failed
-- Performing Test HAVE_CXX_FDIAGNOSTICS_SHOW_OPTION
-- Performing Test HAVE_CXX_FDIAGNOSTICS_SHOW_OPTION - Success
-- Performing Test HAVE_C_FDIAGNOSTICS_SHOW_OPTION
-- Performing Test HAVE_C_FDIAGNOSTICS_SHOW_OPTION - Success
-- Performing Test HAVE_CXX_WNO_LONG_LONG
-- Performing Test HAVE_CXX_WNO_LONG_LONG - Success
-- Performing Test HAVE_C_WNO_LONG_LONG
-- Performing Test HAVE_C_WNO_LONG_LONG - Success
-- Performing Test HAVE_CXX_PTHREAD
-- Performing Test HAVE_CXX_PTHREAD - Success
-- Performing Test HAVE_C_PTHREAD
-- Performing Test HAVE_C_PTHREAD - Success
-- Performing Test HAVE_CXX_FOMIT_FRAME_POINTER
-- Performing Test HAVE_CXX_FOMIT_FRAME_POINTER - Success
-- Performing Test HAVE_C_FOMIT_FRAME_POINTER
-- Performing Test HAVE_C_FOMIT_FRAME_POINTER - Success
-- Performing Test HAVE_CXX_MSSE
-- Performing Test HAVE_CXX_MSSE - Success
-- Performing Test HAVE_C_MSSE
-- Performing Test HAVE_C_MSSE - Success
-- Performing Test HAVE_CXX_MSSE2
-- Performing Test HAVE_CXX_MSSE2 - Success
-- Performing Test HAVE_C_MSSE2
-- Performing Test HAVE_C_MSSE2 - Success
-- Performing Test HAVE_CXX_MSSE3
-- Performing Test HAVE_CXX_MSSE3 - Success
-- Performing Test HAVE_C_MSSE3
-- Performing Test HAVE_C_MSSE3 - Success
-- Performing Test HAVE_CXX_FFUNCTION_SECTIONS
-- Performing Test HAVE_CXX_FFUNCTION_SECTIONS - Success
-- Performing Test HAVE_C_FFUNCTION_SECTIONS
-- Performing Test HAVE_C_FFUNCTION_SECTIONS - Success
-- Performing Test HAVE_CXX_FVISIBILITY_HIDDEN
-- Performing Test HAVE_CXX_FVISIBILITY_HIDDEN - Success
-- Performing Test HAVE_C_FVISIBILITY_HIDDEN
-- Performing Test HAVE_C_FVISIBILITY_HIDDEN - Success
-- Performing Test HAVE_CXX_FVISIBILITY_INLINES_HIDDEN
-- Performing Test HAVE_CXX_FVISIBILITY_INLINES_HIDDEN - Success
-- Performing Test HAVE_C_FVISIBILITY_INLINES_HIDDEN
-- Performing Test HAVE_C_FVISIBILITY_INLINES_HIDDEN - Failed
-- Looking for pthread.h
-- Looking for pthread.h - found
-- Check if the system is big endian
-- Searching 16 bit integer
-- Looking for sys/types.h
-- Looking for sys/types.h - found
-- Looking for stdint.h
-- Looking for stdint.h - found
-- Looking for stddef.h
-- Looking for stddef.h - found
-- Check size of unsigned short
-- Check size of unsigned short - done
-- Using unsigned short
-- Check if the system is big endian - little endian
-- Found ZLIB: /usr/lib/x86_64-linux-gnu/libz.so (found suitable version "1.2.3.4", required is "1.2.3")
-- Found TIFF: /usr/lib/x86_64-linux-gnu/libtiff.so 
-- Found JPEG: /usr/lib/x86_64-linux-gnu/libjpeg.so 
-- Performing Test HAVE_C_WNO_UNUSED_VARIABLE
-- Performing Test HAVE_C_WNO_UNUSED_VARIABLE - Success
-- Performing Test HAVE_C_WNO_SHADOW
-- Performing Test HAVE_C_WNO_SHADOW - Success
-- Performing Test HAVE_C_WNO_MAYBE_UNINITIALIZED
-- Performing Test HAVE_C_WNO_MAYBE_UNINITIALIZED - Failed
-- Found Jasper: /usr/lib/x86_64-linux-gnu/libjasper.so 
-- Found ZLIB: /usr/lib/x86_64-linux-gnu/libz.so (found version "1.2.3.4")
-- Found PNG: /usr/lib/x86_64-linux-gnu/libpng.so 
-- Looking for /usr/include/libpng/png.h
-- Looking for /usr/include/libpng/png.h - found
-- Found OpenEXR: /usr/lib/libIlmImf.so
CMake Warning at cmake/OpenCVFindLibsGUI.cmake:18 (find_package):
  Could not find module FindQt5Core.cmake or a configuration file for package
  Qt5Core.

  Adjust CMAKE_MODULE_PATH to find FindQt5Core.cmake or set Qt5Core_DIR to
  the directory containing a CMake configuration file for Qt5Core.  The file
  will have one of the following names:

    Qt5CoreConfig.cmake
    qt5core-config.cmake

Call Stack (most recent call first):
  CMakeLists.txt:447 (include)


CMake Warning at cmake/OpenCVFindLibsGUI.cmake:19 (find_package):
  Could not find module FindQt5Gui.cmake or a configuration file for package
  Qt5Gui.

  Adjust CMAKE_MODULE_PATH to find FindQt5Gui.cmake or set Qt5Gui_DIR to the
  directory containing a CMake configuration file for Qt5Gui.  The file will
  have one of the following names:

    Qt5GuiConfig.cmake
    qt5gui-config.cmake

Call Stack (most recent call first):
  CMakeLists.txt:447 (include)


CMake Warning at cmake/OpenCVFindLibsGUI.cmake:20 (find_package):
  Could not find module FindQt5Widgets.cmake or a configuration file for
  package Qt5Widgets.

  Adjust CMAKE_MODULE_PATH to find FindQt5Widgets.cmake or set Qt5Widgets_DIR
  to the directory containing a CMake configuration file for Qt5Widgets.  The
  file will have one of the following names:

    Qt5WidgetsConfig.cmake
    qt5widgets-config.cmake

Call Stack (most recent call first):
  CMakeLists.txt:447 (include)


CMake Warning at cmake/OpenCVFindLibsGUI.cmake:21 (find_package):
  Could not find module FindQt5Test.cmake or a configuration file for package
  Qt5Test.

  Adjust CMAKE_MODULE_PATH to find FindQt5Test.cmake or set Qt5Test_DIR to
  the directory containing a CMake configuration file for Qt5Test.  The file
  will have one of the following names:

    Qt5TestConfig.cmake
    qt5test-config.cmake

Call Stack (most recent call first):
  CMakeLists.txt:447 (include)


CMake Warning at cmake/OpenCVFindLibsGUI.cmake:22 (find_package):
  Could not find module FindQt5Concurrent.cmake or a configuration file for
  package Qt5Concurrent.

  Adjust CMAKE_MODULE_PATH to find FindQt5Concurrent.cmake or set
  Qt5Concurrent_DIR to the directory containing a CMake configuration file
  for Qt5Concurrent.  The file will have one of the following names:

    Qt5ConcurrentConfig.cmake
    qt5concurrent-config.cmake

Call Stack (most recent call first):
  CMakeLists.txt:447 (include)


-- Looking for Q_WS_X11
-- Looking for Q_WS_X11 - found
-- Looking for Q_WS_WIN
-- Looking for Q_WS_WIN - not found.
-- Looking for Q_WS_QWS
-- Looking for Q_WS_QWS - not found.
-- Looking for Q_WS_MAC
-- Looking for Q_WS_MAC - not found.
-- Found Qt4: /usr/bin/qmake (found version "4.8.1")
-- Looking for XOpenDisplay in /usr/lib/x86_64-linux-gnu/libX11.so;/usr/lib/x86_64-linux-gnu/libXext.so
-- Looking for XOpenDisplay in /usr/lib/x86_64-linux-gnu/libX11.so;/usr/lib/x86_64-linux-gnu/libXext.so - found
-- Looking for gethostbyname
-- Looking for gethostbyname - found
-- Looking for connect
-- Looking for connect - found
-- Looking for remove
-- Looking for remove - found
-- Looking for shmat
-- Looking for shmat - found
-- Looking for IceConnectionNumber in ICE
-- Looking for IceConnectionNumber in ICE - found
-- Found X11: /usr/lib/x86_64-linux-gnu/libX11.so
-- checking for module 'gstreamer-base-1.0'
--   package 'gstreamer-base-1.0' not found
-- checking for module 'gstreamer-video-1.0'
--   package 'gstreamer-video-1.0' not found
-- checking for module 'gstreamer-app-1.0'
--   package 'gstreamer-app-1.0' not found
-- checking for module 'gstreamer-riff-1.0'
--   package 'gstreamer-riff-1.0' not found
-- checking for module 'gstreamer-pbutils-1.0'
--   package 'gstreamer-pbutils-1.0' not found
-- checking for module 'gstreamer-base-0.10'
--   found gstreamer-base-0.10, version 0.10.36
-- checking for module 'gstreamer-video-0.10'
--   found gstreamer-video-0.10, version 0.10.36
-- checking for module 'gstreamer-app-0.10'
--   found gstreamer-app-0.10, version 0.10.36
-- checking for module 'gstreamer-riff-0.10'
--   found gstreamer-riff-0.10, version 0.10.36
-- checking for module 'gstreamer-pbutils-0.10'
--   found gstreamer-pbutils-0.10, version 0.10.36
-- checking for module 'libdc1394-2'
--   found libdc1394-2, version 2.2.0
-- checking for module 'libv4l1'
--   found libv4l1, version 0.8.6
-- Looking for linux/videodev.h
-- Looking for linux/videodev.h - not found
-- Looking for linux/videodev2.h
-- Looking for linux/videodev2.h - found
-- Looking for sys/videoio.h
-- Looking for sys/videoio.h - not found
-- checking for module 'libavcodec'
--   found libavcodec, version 53.35.0
-- checking for module 'libavformat'
--   found libavformat, version 53.21.1
-- checking for module 'libavutil'
--   found libavutil, version 51.22.2
-- checking for module 'libswscale'
--   found libswscale, version 2.1.0
-- Looking for libavformat/avformat.h
-- Looking for libavformat/avformat.h - found
-- Looking for ffmpeg/avformat.h
-- Looking for ffmpeg/avformat.h - not found
-- checking for module 'tbb'
--   found tbb, version 3.0+r018
CMake Warning at 3rdparty/ippicv/downloader.cmake:54 (message):
  ICV: Local copy of ICV package has invalid MD5 hash:
  9a7fea9124cb057264446ab1c7f5841d (expected:
  d80cb24f3a565113a9d6dc56344142f6)
Call Stack (most recent call first):
  3rdparty/ippicv/downloader.cmake:108 (_icv_downloader)
  cmake/OpenCVFindIPP.cmake:212 (include)
  cmake/OpenCVFindLibsPerf.cmake:12 (include)
  CMakeLists.txt:449 (include)


-- ICV: Downloading ippicv_linux_20140513.tgz...
CMake Error at 3rdparty/ippicv/downloader.cmake:71 (file):
  file DOWNLOAD MD5 mismatch

    for file: [/home/clive/OpenCV/opencv-3.0.0-alpha/3rdparty/ippicv/downloads/linux-d80cb24f3a565113a9d6dc56344142f6/ippicv_linux_20140513.tgz]
      expected MD5 sum: [d80cb24f3a565113a9d6dc56344142f6]
        actual MD5 sum: [ad7124f0fc04a24f6c725d2dbbc436db]

Call Stack (most recent call first):
  3rdparty/ippicv/downloader.cmake:108 (_icv_downloader)
  cmake/OpenCVFindIPP.cmake:212 (include)
  cmake/OpenCVFindLibsPerf.cmake:12 (include)
  CMakeLists.txt:449 (include)


CMake Error at 3rdparty/ippicv/downloader.cmake:75 (message):
  ICV: Failed to download ICV package: ippicv_linux_20140513.tgz.
  Status=28;"Timeout was reached"
Call Stack (most recent call first):
  3rdparty/ippicv/downloader.cmake:108 (_icv_downloader)
  cmake/OpenCVFindIPP.cmake:212 (include)
  cmake/OpenCVFindLibsPerf.cmake:12 (include)
  CMakeLists.txt:449 (include)


-- Configuring incomplete, errors occurred!
 

Why are the checksums different? Is it because OpenCV3.0 needs another version of ippicv? I understand that the error comes while downloading ippicv_linux_20140513.tgz (in the 3rd party, ippicv folder).

Can someone help me out here? Any help would be appreciated!

PS. I want to use OpenCV3.0 with Python. OpenCV2.4.9 was working well until I tried to remove it. I actually deleted every file with the name "opencv" from my system. I didn't know how to uninstall it the proper way.