Cam-e-lot - Round 3 - Man vs OpenCV

Hello everybody

For my project I need to make some analysis on the images captured by RaspiCam, so the next step is to install the OpenCV libraries and try to get images from RaspiCam inside a C program.

So here are the steps for this round (this tutorial has been adapted from the tutorial published by Pierre on Think RPI | Creative Raspberry Pi Area)

1. Install RaspiCam. Installation procedure is very well described on Raspberry official site http://www.raspberrypi.org/archives/3890 Once installed, test it with this command:

raspistill -t 10000

2. Download the MMAL library aspivid/Raspistill source code from https://github.com/raspberrypi/userland .

3. Unzip the file and copy the directory userlan-master in /opt/vc. I also renamed the directory as "userland"

4.  Go to /opt/vc/userland and type

     sed -i ‘s/if (DEFINED CMAKE_TOOLCHAIN_FILE)/if (NOT DEFINED CMAKE_TOOLCHAIN_FILE)/g’ makefiles/cmake/arm-linux.cmake

5. create a build directory...

     sudo mkdir build

     cd build

6. ... and compile

     sudo cmake -DCMAKE_BUILD_TYPE=Release ..
     sudo make
     sudo make install

7. go to /opt/vc/bin and test one file typing : ./raspistill -t 3000

OK... now I'm ready to create a new project

1. create a new folder (/home/pi/vc) in your home directory

     mkdir cv
     cd cv

2. copy all raspicam apps source code

     cp /opt/vc/userland/host_applications/linux/apps/raspicam/*  .

     mv RaspiStill.c camcv.c

     sudo chmod 777 camcv.c

3. remove then content of CMakeLists.txt and replace with :
     cmake_minimum_required(VERSION 2.8)
     project( camcv )
     SET(COMPILE_DEFINITIONS -Werror)
     include_directories(/opt/vc/userland/host_applications/linux/libs/bcm_host/include)
     include_directories(/opt/vc/userland/interface/vcos)
     include_directories(/opt/vc/userland)
     include_directories(/opt/vc/userland/interface/vcos/pthreads)
     include_directories(/opt/vc/userland/interface/vmcs_host/linux)
     include_directories(/opt/vc/userland/interface/khronos/include)

     include_directories(/opt/vc/userland/interface/khronos/common)

     add_executable(camcv RaspiCamControl.c RaspiCLI.c RaspiPreview.c camcv.c RaspiText.c RaspiTexUtil.c gl_scenes/teapot.c gl_scenes/models.c gl_scenes/square.c gl_scenes/mirror.c gl_scenes/yuv.c gl_scenes/sobel.c tga.c)
     target_link_libraries(camcv /opt/vc/lib/libmmal_core.so /opt/vc/lib/libmmal_util.so /opt/vc/lib/libmmal_vc_client.so /opt/vc/lib/libvcos.so /opt/vc/lib/libbcm_host.so /opt/vc/lib/libGLESv2.so /opt/vc/lib/libEGL.so)

4. delete CMakeFiles directory if it exits
5. compile & test
     cmake .
     make
     ./camcv -t 1000

Great!!!

We are now ready to install OpenCV

1. install both dev lib and python lib. Even if I'm going to use pure C for development, Python is still useful for small scripts, so I recommend to install it.

     sudo apt-get update

     sudo apt-get install libopencv-dev
     sudo apt-get install python-opencv

2. to test if OpenCv library is well installed, write this test software. It just displays a picture using imread and imshow functions. You will need to provide a sample .jpg file. To compile using OpenCv lib, create a CMakeLists.txt file with the following lines

     cmake_minimum_required(VERSION 2.8)
     project( displayimage )
     find_package( OpenCV REQUIRED )
     add_executable( displayimage display_image.cpp )
     target_link_libraries( displayimage ${OpenCV_LIBS} )

3. compile and execute

     cmake .
     make
     ./displayimage

4. Modify your CMakeFiles.txt to include OpenCV library

     project( camcv )

     SET(COMPILE_DEFINITIONS -Werror)

     #OPENCV
     find_package( OpenCV REQUIRED )

     include_directories(/opt/vc/userland/host_applications/linux/libs/bcm_host/include)

     include_directories(/opt/vc/userland/interface/vcos)
     include_directories(/opt/vc/userland)
     include_directories(/opt/vc/userland/interface/vcos/pthreads)
     include_directories(/opt/vc/userland/interface/vmcs_host/linux)
     include_directories(/opt/vc/userland/interface/khronos/include)

     include_directories(/opt/vc/userland/interface/khronos/common)

     add_executable(camcv RaspiCamControl.c RaspiCLI.c RaspiPreview.c camcv.c RaspiText.c RaspiTexUtil.c gl_scenes/teapot.c gl_scenes/models.c gl_scenes/square.c gl_scenes/mirror.c gl_scenes/yuv.c gl_scenes/sobel.c tga.c)
     target_link_libraries(camcv /opt/vc/lib/libmmal_core.so /opt/vc/lib/libmmal_util.so /opt/vc/lib/libmmal_vc_client.so /opt/vc/lib/libvcos.so /opt/vc/lib/libbcm_host.so /opt/vc/lib/libGLESv2.so /opt/vc/lib/libEGL.so ${OpenCV_LIBS})

5. Recompile. It should be ok, because we didn't change anything in the source code

     make
     ./camcv

I'm sorry this has been a very boring post with a little more than some shell scripting... In next post I will make a basic application that can capture an image from RaspiCam and make some video processing using the power of the OpenCV library

Stay tuned!