Using OpenCV on iPhone

This source repository does NOT include pre-compiled OpenCV library or headers! It helps you building yours, from OpenCV source code. More documents you can see on this article, but it is kinda old now. As far as I can see, the original repo is not maintained anymore. I'm not sure to let the XCode project in future release, it is more noise than anything in the repo. If anyone is annoyed by this, please tell me!

Build every versions in one pass

Build support script opencv_cmake.sh has some options to build OpenCV with iOS SDK. Try --help option to get the all options of it. By default, the iOS SDK 5.0 is used. It supposed you use XCode 4.2, situated in directory /Developer

Script make_all.sh uses opencv_cmake.sh to build the simulator version, the device version and the universal version (both i386 and armv6/7) in one pass. Just give it the OpenCV version as a parameter. You must have the OpenCV archive in the same directory. BE CAREFUL with last version 2.3.1a, the last a breaks the script, so please, rename the archive as OpenCV-2.3.1.tar.bz2. This script uses make -j 4 specifying that 4 building jobs are run simultaneously. You should probably adapt this to your own configuration.

Modifications to the original sources

To be usable to use the whole library both on the simulator and on the device, I had to remove some parts of highgui like Cocoa and QuickTime support. Removing the whole highgui package prevents you to build on the simulator with some libraries linked.

Here is the list of all the files I've changed (see the patch for further details):

1. into features2d/oneway.cpp

    - OneWayDescriptor::Save() does not save image anymore ;
    - function loadPCAFeatures() does not extractPatches() as before, this is probably a problem if you use it...
   

2. into objdetect/latentsvmdetector.cpp

    - function cvLatentSvmDetectObjects() does not swap red and blue components before and after its process.
   

3. into objdetect/latentsvm.cpp

    - functions showRootFilterBoxes(), showPartFilterBoxes() and showBoxes() does not show image anymore.
   

4. into contrib/chamfermatching.cpp

    - function ChamferMatcher::Template::show() does not show image anymore.
   

If you know some way to recover these functionalities without breaking the build, you can propose a different patch.

After these modifications, I've produced the patch with the command:

		diff -crB OpenCV-VERSION ../OpenCV-VERSION > OpenCV-VERSION.patch

with ../OpenCV-VERSION the directory containing the modified version.

Building Static Link Version of OpenCV

If you want to build it from source code, you can do by next steps.

1. Building OpenCV requires CMake. You can easily install it by using Homebrew or MacPorts.

   # Using Homebrew
   % brew install cmake
   # Using MacPorts
   % sudo port install cmake
   

2. Clone this project from github.com, then move into the project directory

   % git clone git://github.com/stephanepechard/iphone_opencv_test.git
   

3. Getting source code from sourceforge. I tested with OpenCV-2.3.1.tar.bz2.

4. Extract downloaded archive on the top of demo project directory

   % tar xjvf OpenCV-2.3.1.tar.bz2
   

5. Apply patch for iPhone SDK

   % cd OpenCV-2.3.1
   % patch -p1 < ../OpenCV-2.3.1.patch
   

6. Following next steps to build OpenCV static library for simulator. All files are installed into opencv_simulator directory. When running make command, you've better assign -j option and number according to number of your CPU cores. Without -j option, it takes a long time.

   % cd ..
   % mkdir build_simulator
   % cd build_simulator
   % ../opencv_cmake.sh Simulator ../OpenCV-2.3.1
   % make -j 4
   % make install
   

7. Following next steps to build OpenCV static library for device All files are installed into opencv_device directory.

   % cd ..
   % mkdir build_device
   % cd build_device
   % ../opencv_cmake.sh Device ../OpenCV-2.3.1
   % make -j 4
   % make install
   

Change Log

• 12/07/2011 - Support OpenCV 2.3.1 + iOS SDK 5.0.1 + XCode 4.2.1 + Mac OS X 10.7 Cleaner make_all.sh script. Allows building highgui with some removed functionalities.
• 09/23/2011 - Support OpenCV 2.3.1 + iOS SDK 5.0 + XCode 4 [first stephanepechard commit]
• 04/11/2011 - Support OpenCV 2.2.0 + iOS SDK 4.3 + XCode 4
• 10/30/2010 - Support iOS SDK 4.1
• 08/22/2010 - Support OpenCV 2.1.0 + iOS SDK 4.0
• 12/21/2009 - Support Snow Leopard + iPhone SDK 3.1.2, Thank you Hyon!
• 11/15/2009 - Support OpenCV to 2.0.0 + iPhone SDK 3.x
• 03/14/2009 - Release this project with OpenCV 1.0.0 + iPhone SDK 2.x