title: How to install OpenCV on OS X Lion using brew
body: <p>i'm trying to install opencv libraries using brew.
  i tried:</p>
  
  <pre><code>sudo brew install opencv
  </code></pre>
  
  <p>this is the output:</p>
  
  <pre><code>user$ sudo brew install opencv
  sudo: /var/db/sudo writable by non-owner (040777), should be mode 0700
  
  WARNING: Improper use of the sudo command could lead to data loss
  or the deletion of important system files. Please double-check your
  typing when using sudo. Type "man sudo" for more information.
  
  To proceed, enter your password, or type Ctrl-C to abort.
  
  Password:
  /usr/local/Library/Homebrew/global.rb:64: warning: Insecure world writable dir /opt/local in PATH, mode 040777
  /usr/local/bin/brew:74: warning: Insecure world writable dir /opt/local in PATH, mode 040777
  Warning: It appears you have MacPorts or Fink installed.
  Software installed with other package managers causes known problems for
  Homebrew. If a formula fails to build, uninstall MacPorts/Fink and try again.
  /usr/local/Library/Homebrew/build.rb:7: warning: Insecure world writable dir /opt/local in PATH, mode 040777
  ==&gt; Downloading http://sourceforge.net/projects/opencvlibrary/files/opencv-unix/2.3.1/OpenCV-2.3.1a.tar.bz2
  File already downloaded in /Library/Caches/Homebrew
  ==&gt; Patching
  patching file modules/highgui/src/grfmt_exr.hpp
  ==&gt; cmake . -DCMAKE_INSTALL_PREFIX='/usr/local/Cellar/opencv/2.3.1a' -DCMAKE_BUILD_TYPE=None -Wno-dev -DPYTHON_LIBRARY='/System/Library/Frameworks/Python.framework/Versions/2.7/Python' -DP
  ==&gt; make
  Scanning dependencies of target opencv_core
  [  1%] [  1%] Building CXX object modules/core/CMakeFiles/opencv_core.dir/src/arithm.o
  Building CXX object modules/core/CMakeFiles/opencv_core.dir/src/alloc.o
  [  1%] Building CXX object modules/core/CMakeFiles/opencv_core.dir/src/array.o
  [  1%] Building CXX object modules/core/CMakeFiles/opencv_core.dir/src/cmdparser.o
  [  1%] Building CXX object modules/core/CMakeFiles/opencv_core.dir/src/convert.o
  [  2%] Building CXX object modules/core/CMakeFiles/opencv_core.dir/src/copy.o
  [  2%] Building CXX object modules/core/CMakeFiles/opencv_core.dir/src/datastructs.o
  [  2%] Building CXX object modules/core/CMakeFiles/opencv_core.dir/src/drawing.o
  [  2%] Building CXX object modules/core/CMakeFiles/opencv_core.dir/src/dxt.o
  [  3%] Building CXX object modules/core/CMakeFiles/opencv_core.dir/src/lapack.o
  [  3%] Building CXX object modules/core/CMakeFiles/opencv_core.dir/src/mathfuncs.o
  [  3%] Building CXX object modules/core/CMakeFiles/opencv_core.dir/src/matmul.o
  [  3%] Building CXX object modules/core/CMakeFiles/opencv_core.dir/src/matop.o
  [  4%] Building CXX object modules/core/CMakeFiles/opencv_core.dir/src/matrix.o
  [  4%] Building CXX object modules/core/CMakeFiles/opencv_core.dir/src/out.o
  [  4%] Building CXX object modules/core/CMakeFiles/opencv_core.dir/src/persistence.o
  [  4%] Building CXX object modules/core/CMakeFiles/opencv_core.dir/src/precomp.o
  [  5%] Building CXX object modules/core/CMakeFiles/opencv_core.dir/src/rand.o
  [  5%] Building CXX object modules/core/CMakeFiles/opencv_core.dir/src/stat.o
  [  5%] Building CXX object modules/core/CMakeFiles/opencv_core.dir/src/system.o
  [  5%] Building CXX object modules/core/CMakeFiles/opencv_core.dir/src/tables.o
  Linking CXX shared library ../../lib/libopencv_core.dylib
  [  5%] Built target opencv_core
  Scanning dependencies of target opencv_flann
  [  6%] Building CXX object modules/flann/CMakeFiles/opencv_flann.dir/src/flann.o
  Scanning dependencies of target opencv_imgproc
  [  6%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/accum.o
  In file included from /tmp/homebrew-opencv-2.3.1a-dWXV/OpenCV-2.3.1/modules/flann/src/flann.cpp:29:
  In file included from /tmp/homebrew-opencv-2.3.1a-dWXV/OpenCV-2.3.1/modules/flann/src/precomp.hpp:17:
  In file included from /tmp/homebrew-opencv-2.3.1a-dWXV/OpenCV-2.3.1/modules/flann/include/opencv2/flann/all_indices.h:42:
  /tmp/homebrew-opencv-2.3.1a-dWXV/OpenCV-2.3.1/modules/flann/include/opencv2/flann/lsh_index.h:89:81: error: no matching constructor for initialization of 'cvflann::LshIndexParams'
      LshIndex(const Matrix&lt;ElementType&gt;&amp; input_data, const IndexParams&amp; params = LshIndexParams(),
                                                                                  ^
  /tmp/homebrew-opencv-2.3.1a-dWXV/OpenCV-2.3.1/modules/flann/include/opencv2/flann/lsh_index.h:59:5: note: candidate constructor not viable: requires 3 arguments, but 0 were provided
      LshIndexParams(unsigned int table_number, unsigned int key_size, unsigned int multi_probe_level)
      ^
  /tmp/homebrew-opencv-2.3.1a-dWXV/OpenCV-2.3.1/modules/flann/include/opencv2/flann/lsh_index.h:57:8: note: candidate constructor (the implicit copy constructor) not viable: requires 1 argument, but 0 were provided
  struct LshIndexParams : public IndexParams
         ^
  In file included from /tmp/homebrew-opencv-2.3.1a-dWXV/OpenCV-2.3.1/modules/flann/src/flann.cpp:29:
  In file included from /tmp/homebrew-opencv-2.3.1a-dWXV/OpenCV-2.3.1/modules/flann/src/precomp.hpp:10:
  In file included from /tmp/homebrew-opencv-2.3.1a-dWXV/OpenCV-2.3.1/modules/flann/include/opencv2/flann/index_testing.h:39:
  In file included from /tmp/homebrew-opencv-2.3.1a-dWXV/OpenCV-2.3.1/modules/flann/include/opencv2/flann/nn_index.h:39:
  In file included from /tmp/homebrew-opencv-2.3.1a-dWXV/OpenCV-2.3.1/modules/flann/include/opencv2/flann/params.h:33:
  /tmp/homebrew-opencv-2.3.1a-dWXV/OpenCV-2.3.1/modules/flann/include/opencv2/flann/any.h:88:67: error: call to function 'operator&lt;&lt;' that is neither visible in the template definition nor found by argument-dependent lookup
      virtual void print(std::ostream&amp; out, void* const* src) { out &lt;&lt; *reinterpret_cast&lt;T const*&gt;(*src); }
                                                                    ^
  /tmp/homebrew-opencv-2.3.1a-dWXV/OpenCV-2.3.1/modules/flann/include/opencv2/flann/any.h:136:44: note: in instantiation of member function 'cdiggins::anyimpl::big_any_policy&lt;cdiggins::anyimpl::empty_any&gt;::print' requested here
      static typename choose_policy&lt;T&gt;::type policy;
                                             ^
  /tmp/homebrew-opencv-2.3.1a-dWXV/OpenCV-2.3.1/modules/flann/include/opencv2/flann/any.h:159:18: note: in instantiation of function template specialization 'cdiggins::anyimpl::get_policy&lt;cdiggins::anyimpl::empty_any&gt;' requested here
          : policy(anyimpl::get_policy&lt;anyimpl::empty_any&gt;()), object(NULL)
                   ^
  /tmp/homebrew-opencv-2.3.1a-dWXV/OpenCV-2.3.1/modules/flann/include/opencv2/flann/any.h:276:22: note: 'operator&lt;&lt;' should be declared prior to the call site or in namespace 'cdiggins::anyimpl'
  inline std::ostream&amp; operator &lt;&lt;(std::ostream&amp; out, const any&amp; any_val)
                       ^
  2 errors generated.
  make[2]: *** [modules/flann/CMakeFiles/opencv_flann.dir/src/flann.o] Error 1
  make[1]: *** [modules/flann/CMakeFiles/opencv_flann.dir/all] Error 2
  make[1]: *** Waiting for unfinished jobs....
  [  7%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/approx.o
  [  7%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/canny.o
  [  7%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/color.o
  [  7%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/contours.o
  [  8%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/convhull.o
  [  8%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/corner.o
  [  8%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/cornersubpix.o
  [  8%] [  9%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/deriv.o
  Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/distransform.o
  [  9%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/emd.o
  [  9%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/featureselect.o
  [  9%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/featuretree.o
  [ 10%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/filter.o
  [ 10%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/floodfill.o
  [ 10%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/geometry.o
  [ 10%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/grabcut.o
  [ 11%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/histogram.o
  [ 11%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/hough.o
  [ 11%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/imgwarp.o
  [ 11%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/inpaint.o
  [ 12%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/kdtree.o
  [ 12%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/linefit.o
  [ 12%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/lsh.o
  [ 12%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/matchcontours.o
  [ 12%] [ 13%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/moments.o
  Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/morph.o
  [ 13%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/precomp.o
  [ 13%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/pyramids.o
  [ 13%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/pyrsegmentation.o
  [ 14%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/rotcalipers.o
  [ 14%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/samplers.o
  [ 14%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/segmentation.o
  [ 14%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/shapedescr.o
  [ 15%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/smooth.o
  [ 15%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/spilltree.o
  [ 15%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/subdivision2d.o
  [ 15%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/sumpixels.o
  [ 16%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/tables.o
  [ 16%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/templmatch.o
  [ 16%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/thresh.o
  [ 16%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/undistort.o
  [ 17%] Building CXX object modules/imgproc/CMakeFiles/opencv_imgproc.dir/src/utils.o
  Linking CXX shared library ../../lib/libopencv_imgproc.dylib
  [ 17%] Built target opencv_imgproc
  make: *** [all] Error 2
  CMakeCache.txt was copied to /Users/turchijacopo/Library/Logs/Homebrew
  ==&gt; Exit Status: 2
  http://github.com/mxcl/homebrew/blob/master/Library/Formula/opencv.rb#L76
  ==&gt; Environment
  HOMEBREW_VERSION: 0.8.1
  HEAD: 3b771d09e48f4dfa88ef4c5d32f3b84ca2ae18ec
  HOMEBREW_PREFIX: /usr/local
  HOMEBREW_CELLAR: /usr/local/Cellar
  Hardware: dual-core 64-bit penryn
  OS X: 10.7.3
  Kernel Architecture: x86_64
  Xcode: 4.3.1
  GCC-4.0: N/A
  GCC-4.2: N/A
  LLVM: build 2336
  Clang: 3.0 build 211
  MacPorts or Fink? /opt/local/bin/port
  X11: /usr/X11
  System Ruby: 1.8.7-249
  /usr/bin/ruby =&gt; /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby
  Which Perl:   /usr/bin/perl
  Which Python: /usr/bin/python
  Which Ruby:   /usr/bin/ruby =&gt; /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby
  ==&gt; Build Flags
  CC: /usr/bin/clang
  CXX: /usr/bin/clang++ =&gt; /usr/bin/clang
  LD: /usr/bin/clang
  CFLAGS: -Os -w -pipe -march=native -Qunused-arguments
  CXXFLAGS: -Os -w -pipe -march=native -Qunused-arguments
  MAKEFLAGS: -j2
  
  Error: Failed executing: make 
  These existing issues may help you:
      https://github.com/mxcl/homebrew/issues/10862
  Otherwise, please report the bug:
      https://github.com/mxcl/homebrew/wiki/checklist-before-filing-a-new-issue
  </code></pre>
  
  <p>what can i do ?</p>