Cross compile opencv project on Ubuntu for Raspberry Pi

Question

I'm struggling with this for 2 days now and don't get it to work.

What I've done so far:

• built opencv 2.4.8 from source on Ubuntu 12.04 LTS --> OpenCV projects compile and run on ubuntu

• built opencv 2.4.8 from source on the Raspberry Pi Raspian --> OpenCV projects compile and run on the Raspberry Pi

• built a cross compiler for the Raspberry Pi with crosstools-ng (http://www.bootc.net/archives/2012/05/26/how-to-build-a-cross-compiler-for-your-raspberry-pi/) --> c++ programs built on Ubuntu with the crosscompiler run on the Raspberry Pi

---

What are my problems:

OpenCV programs don't compile with the cross compiler

|2|fatal error: opencv2/highgui/highgui.hpp: No such file or directory|

I think I need to cross compile OpenCV as well on ubuntu. From my cross compiler I also have a toolchain

# this one is important
SET(CMAKE_SYSTEM_NAME Linux)
#this one not so much
SET(CMAKE_SYSTEM_VERSION 1)

# specify the cross compiler
SET(CMAKE_C_COMPILER
/home/christian/Programming/x-tools/arm-unknown-linux-gnueabi/bin/arm-unknown-linux-gnueabi-gcc)

SET(CMAKE_CXX_COMPILER
/home/christian/Programming/x-tools/arm-unknown-linux-gnueabi/bin/arm-unknown-linux-gnueabi-g++)

# where is the target environment
SET(CMAKE_FIND_ROOT_PATH
/home/christian/Programming/x-tools/arm-unknown-linux-gnueabi)

# search for programs in the build host directories
SET(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
# for libraries and headers in the target directories
SET(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
SET(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)

with this toolchain I tried to cross compile OpenCV with this command:

cmake -DCMAKE_TOOLCHAIN_FILE=../Toolchain-RaspberryPi.cmake ../

After the make command it compiles until 27%. There it stops with this error

[ 27%] Building CXX object modules/highgui/CMakeFiles/opencv_highgui.dir/src/cap_ffmpeg.cpp.o
In file included from /home/christian/Downloads/opencv-2.4.8/modules/highgui/src/cap_ffmpeg_impl.hpp:60:0,
                 from /home/christian/Downloads/opencv-2.4.8/modules/highgui/src/cap_ffmpeg.cpp:45:
/home/christian/Downloads/opencv-2.4.8/modules/highgui/src/ffmpeg_codecs.hpp:81:36: fatal error: libavformat/avformat.h: No such file or directory
   #include <libavformat/avformat.h>
                                    ^
compilation terminated.
make[2]: *** [modules/highgui/CMakeFiles/opencv_highgui.dir/src/cap_ffmpeg.cpp.o] Error 1
make[1]: *** [modules/highgui/CMakeFiles/opencv_highgui.dir/all] Error 2
make: *** [all] Error 2

I tried to copy the OpenCV headers and libs compiled on the Raspberry Pi to my ubuntu computer and link them. I get loads of errors while compiling

||=== RPi_Cross_CV, Debug ===|
||warning: libz.so.1, needed by ../../../../Programming/x-tools/usr-local/lib/libopencv_core.so.2.4.8, not found (try using -rpath or -rpath-link)|
||warning: libjpeg.so.8, needed by ../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8, not found (try using -rpath or -rpath-link)|
||warning: libpng12.so.0, needed by ../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8, not found (try using -rpath or -rpath-link)|
||warning: libtiff.so.4, needed by ../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8, not found (try using -rpath or -rpath-link)|
||warning: libjasper.so.1, needed by ../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8, not found (try using -rpath or -rpath-link)|
||warning: libgtk-x11-2.0.so.0, needed by ../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8, not found (try using -rpath or -rpath-link)|
||warning: libgdk-x11-2.0.so.0, needed by ../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8, not found (try using -rpath or -rpath-link)|
||warning: libatk-1.0.so.0, needed by ../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8, not found (try using -rpath or -rpath-link)|
||warning: libgio-2.0.so.0, needed by ../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8, not found (try using -rpath or -rpath-link)|
||warning: libpangoft2-1.0.so.0, needed by ../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8, not found (try using -rpath or -rpath-link)|
||warning: libpangocairo-1.0.so.0, needed by ../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8, not found (try using -rpath or -rpath-link)|
||warning: libgdk_pixbuf-2.0.so.0, needed by ../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8, not found (try using -rpath or -rpath-link)|
||warning: libcairo.so.2, needed by ../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8, not found (try using -rpath or -rpath-link)|
||warning: libpango-1.0.so.0, needed by ../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8, not found (try using -rpath or -rpath-link)|
||warning: libfreetype.so.6, needed by ../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8, not found (try using -rpath or -rpath-link)|
||warning: libfontconfig.so.1, needed by ../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8, not found (try using -rpath or -rpath-link)|
||warning: libgobject-2.0.so.0, needed by ../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8, not found (try using -rpath or -rpath-link)|
||warning: libglib-2.0.so.0, needed by ../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8, not found (try using -rpath or -rpath-link)|
||warning: libgthread-2.0.so.0, needed by ../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8, not found (try using -rpath or -rpath-link)|
||warning: libgstbase-0.10.so.0, needed by ../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8, not found (try using -rpath or -rpath-link)|
||warning: libgstreamer-0.10.so.0, needed by ../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8, not found (try using -rpath or -rpath-link)|
||warning: libgmodule-2.0.so.0, needed by ../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8, not found (try using -rpath or -rpath-link)|
||warning: libxml2.so.2, needed by ../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8, not found (try using -rpath or -rpath-link)|
||warning: libdc1394.so.22, needed by ../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8, not found (try using -rpath or -rpath-link)|
||warning: libv4l1.so.0, needed by ../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8, not found (try using -rpath or -rpath-link)|
||warning: libavcodec.so.53, needed by ../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8, not found (try using -rpath or -rpath-link)|
||warning: libavformat.so.53, needed by ../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8, not found (try using -rpath or -rpath-link)|
||warning: libavutil.so.51, needed by ../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8, not found (try using -rpath or -rpath-link)|
||warning: libswscale.so.2, needed by ../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8, not found (try using -rpath or -rpath-link)|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `TIFFSetWarningHandler@LIBTIFF_3.9'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `png_read_info@PNG12_0'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `g_time_val_add'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `jas_image_writecmpt'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `gtk_widget_queue_draw'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `av_guess_codec@LIBAVFORMAT_53'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `av_rescale_q@LIBAVUTIL_51'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `jpeg_std_error@LIBJPEG_8.0'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `jas_cmprof_destroy'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `png_get_tRNS@PNG12_0'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `g_return_if_fail_warning'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `dc1394_camera_enumerate'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `dc1394_capture_stop'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `compress'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `dc1394_get_image_size_from_video_mode'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `g_timeout_add'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `png_set_packing@PNG12_0'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `v4l2_munmap'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `dc1394_feature_whitebalance_get_value'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `gtk_type_new'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `jas_image_destroy'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `avcodec_close@LIBAVCODEC_53'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `sws_getCachedContext@LIBSWSCALE_2'|
../../../../Programming/x-tools/usr-local/lib/libopencv_core.so.2.4.8||undefined reference to `gzeof'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `gtk_style_attach'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `gtk_widget_get_type'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `gtk_window_resize'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `g_cond_broadcast'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `dc1394_video_get_supported_framerates'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `jpeg_read_header@LIBJPEG_8.0'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `avio_open@LIBAVFORMAT_53'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `TIFFReadEncodedTile@LIBTIFF_3.9'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `uncompress'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `g_type_check_instance_cast'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `g_usleep'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `avcodec_find_decoder@LIBAVCODEC_53'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `g_get_current_time'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `jpeg_set_defaults@LIBJPEG_8.0'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `dc1394_video_get_mode'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `jpeg_start_compress@LIBJPEG_8.0'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `av_free_packet@LIBAVCODEC_53'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `gtk_window_set_geometry_hints'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `gtk_signal_connect_full'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `gdk_draw_rgb_image'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `gtk_widget_queue_resize'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `dc1394_video_set_mode'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `jas_stream_close'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `jpeg_set_quality@LIBJPEG_8.0'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `jas_image_readcmpt'|
../../../../Programming/x-tools/usr-local/lib/libopencv_highgui.so.2.4.8||undefined reference to `gtk_disable_setlocale'|
||More errors follow but not being shown.|
||Edit the max errors limit in compiler options...|
||=== Build finished: 50 errors, 29 warnings ===|

---

So my question is:

How can I get a crosscompiler on ubuntu to work with opencv? I just want to compile on ubuntu, copy the program on the Pi and run it there.

Thanks a lot

Answer 1

I realize this is an old question but for the record I was able to cross compile my OpenCV project from Ubuntu.

In my case I used the the pre-built raspberry pi toolchain on github: https://github.com/raspberrypi/tools on Ubuntu 12.0.4. I took the approach of copying the native libraries (with OpenCV and PiCamera libraries installed) from the target Raspberry Pi system to the Ubuntu instance and using the CMAKE_TOOLCHAIN_FILE support like you mention in your post.

However, there were certain issues I had to overcome, which I cover in this post: https://solderspot.wordpress.com/2016/02/04/cross-compiling-for-raspberry-pi-part-ii

The key points were:

1. CMAKE_FIND_ROOT_PATH had not effect. I had to use CMAKE_SYSROOT.

2. In my CMakeLists.txt file I still had to explicitly prepend any paths with the path to the folder where I had copied over the native file system.

3. I also needed to explicitly specify the dynamic library link paths from within CMAKE_TOOLCHAIN_FILE as the toolchain does not correctly parser the /usr/etc/ld.so.conf file.

The only current issue I could not solve yet was to do with the Jessie release of Raspbian, as OpenCV uses an gcc/g++ 4.9 feature that is not supported by the gcc/g++ 4.8 version of the toolchain. It looks like the toolchain will be augmented to support 4.9 in the near future.

My final CMAKE_TOOLCHAIN_FILE was:

SET(CMAKE_SYSTEM_NAME Linux)
SET(CMAKE_SYSTEM_VERSION 1)

SET(DEVROOT $ENV{HOME}/pidev)
SET(PIROOT ${DEVROOT}/piroot)
SET(PITOOLS ${DEVROOT}/pitools)

SET(TOOLROOT ${PITOOLS}/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian-x64)

# specify the cross compiler
SET(CMAKE_C_COMPILER   ${TOOLROOT}/bin/arm-linux-gnueabihf-gcc)
SET(CMAKE_CXX_COMPILER ${TOOLROOT}/bin/arm-linux-gnueabihf-g++)

SET(FLAGS "-Wl,-rpath-link,${PIROOT}/opt/vc/lib -Wl,-rpath-link,${PIROOT}/lib/arm-linux-gnueabihf -Wl,-rpath-link,${PIROOT}/usr/lib/arm-linux-gnueabihf -Wl,-rpath-link,${PIROOT}/usr/local/lib")

UNSET(CMAKE_C_FLAGS CACHE)
UNSET(CMAKE_CXX_FLAGS CACHE)

SET(CMAKE_CXX_FLAGS ${FLAGS} CACHE STRING "" FORCE)
SET(CMAKE_C_FLAGS ${FLAGS} CACHE STRING "" FORCE)

SET(CMAKE_SYSROOT ${PIROOT})
SET(CMAKE_FIND_ROOT_PATH ${PIROOT})


# search for programs in the build host directories
SET(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
# for libraries and headers in the target directories
SET(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
SET(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)

Where I had a pidev folder in my home directory and under that piroot had a copy of /usr /opt /etc and /lib from my pi host, and pitools is a clone of the toolchain from GitHub I reference above.

My CMakeLists.txt file for my project was:

cmake_minimum_required(VERSION 2.8)
project( PiCamCVTest )
SET(COMPILE_DEFINITIONS -Werror)

include_directories(SYSTEM ${PIROOT}/opt/vc/include ${PIROOT}/opt/vc/include/interface/vcos/pthreads ${PIROOT}/opt/vc/include/interface/vmcs_host/linux )
link_directories( ${PIROOT}/opt/vc/lib )
add_executable(PiCamCVTest main.cpp camera.cpp cameracontrol.cpp graphics.cpp)

target_link_libraries(PiCamCVTest libmmal_core.so libmmal_util.so libmmal_vc_client.so libvcos.so librt.so libbcm_host.so GLESv2 EGL libopencv_core.so libopencv_imgproc.so)

Hope this helps.