Where is opencv in JetPack 4.4?

According to NVIDIA documentation JetPack 4.4 contains opencv 4.1.1. That seems to be confirmed below:

dpkg -l | grep libopencv
ii  libopencv                                     4.1.1-2-gd5a58aa75                               arm64        Open Computer Vision Library
ii  libopencv-dev                                 4.1.1-2-gd5a58aa75                               arm64        Development files for Open Source Computer Vision Library
ii  libopencv-python                              4.1.1-2-gd5a58aa75                               arm64        Python bindings for Open Source Computer Vision Library
ii  libopencv-samples                             4.1.1-2-gd5a58aa75                               arm64        Samples for Open Source Computer Vision Library

But where is it ? pkg-config does not know…

pkg-config opencv --libs
Package opencv was not found in the pkg-config search path.
Perhaps you should add the directory containing `opencv.pc'
to the PKG_CONFIG_PATH environment variable
No package 'opencv' found

I got the following output via python:

python
Python 2.7.17 (default, Sep 30 2020, 13:38:04) 
[GCC 7.5.0] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import cv2
>>> print cv2.getBuildInformation()

General configuration for OpenCV 4.1.1 =====================================
  Version control:               4.1.1-2-gd5a58aa75

  Platform:
    Timestamp:                   2019-12-13T17:25:11Z
    Host:                        Linux 4.9.140-tegra aarch64
    CMake:                       3.10.2
    CMake generator:             Unix Makefiles
    CMake build tool:            /usr/bin/make
    Configuration:               Release

  CPU/HW features:
    Baseline:                    NEON FP16
      required:                  NEON
      disabled:                  VFPV3

  C/C++:
    Built as dynamic libs?:      YES
    C++ Compiler:                /usr/bin/c++  (ver 7.4.0)
    C++ flags (Release):         -fsigned-char -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wundef -Winit-self -Wpointer-arith -Wshadow -Wsign-promo -Wuninitialized -Winit-self -Wsuggest-override -Wno-delete-non-virtual-dtor -Wno-comment -Wimplicit-fallthrough=3 -Wno-strict-overflow -fdiagnostics-show-option -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections    -fvisibility=hidden -fvisibility-inlines-hidden -O3 -DNDEBUG  -DNDEBUG
    C++ flags (Debug):           -fsigned-char -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wundef -Winit-self -Wpointer-arith -Wshadow -Wsign-promo -Wuninitialized -Winit-self -Wsuggest-override -Wno-delete-non-virtual-dtor -Wno-comment -Wimplicit-fallthrough=3 -Wno-strict-overflow -fdiagnostics-show-option -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections    -fvisibility=hidden -fvisibility-inlines-hidden -g  -O0 -DDEBUG -D_DEBUG
    C Compiler:                  /usr/bin/cc
    C flags (Release):           -fsigned-char -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self -Wpointer-arith -Wshadow -Wuninitialized -Winit-self -Wno-comment -Wimplicit-fallthrough=3 -Wno-strict-overflow -fdiagnostics-show-option -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections    -fvisibility=hidden -O3 -DNDEBUG  -DNDEBUG
    C flags (Debug):             -fsigned-char -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self -Wpointer-arith -Wshadow -Wuninitialized -Winit-self -Wno-comment -Wimplicit-fallthrough=3 -Wno-strict-overflow -fdiagnostics-show-option -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections    -fvisibility=hidden -g  -O0 -DDEBUG -D_DEBUG
    Linker flags (Release):      -Wl,--gc-sections  
    Linker flags (Debug):        -Wl,--gc-sections  
    ccache:                      NO
    Precompiled headers:         NO
    Extra dependencies:          dl m pthread rt
    3rdparty dependencies:

  OpenCV modules:
    To be built:                 calib3d core dnn features2d flann gapi highgui imgcodecs imgproc ml objdetect photo python2 python3 stitching ts video videoio
    Disabled:                    world
    Disabled by dependency:      -
    Unavailable:                 java js
    Applications:                tests perf_tests examples apps
    Documentation:               NO
    Non-free algorithms:         NO

  GUI: 
    GTK+:                        YES (ver 2.24.32)
      GThread :                  YES (ver 2.56.4)
      GtkGlExt:                  NO

  Media I/O: 
    ZLib:                        /usr/lib/aarch64-linux-gnu/libz.so (ver 1.2.11)
    JPEG:                        /usr/lib/aarch64-linux-gnu/libjpeg.so (ver 80)
    WEBP:                        build (ver encoder: 0x020e)
    PNG:                         /usr/lib/aarch64-linux-gnu/libpng.so (ver 1.6.34)
    TIFF:                        /usr/lib/aarch64-linux-gnu/libtiff.so (ver 42 / 4.0.9)
    JPEG 2000:                   build (ver 1.900.1)
    HDR:                         YES
    SUNRASTER:                   YES
    PXM:                         YES
    PFM:                         YES

  Video I/O:
    FFMPEG:                      YES
      avcodec:                   YES (57.107.100)
      avformat:                  YES (57.83.100)
      avutil:                    YES (55.78.100)
      swscale:                   YES (4.8.100)
      avresample:                NO
    GStreamer:                   YES (1.14.5)
    v4l/v4l2:                    YES (linux/videodev2.h)

  Parallel framework:            TBB (ver 2017.0 interface 9107)

  Trace:                         YES (with Intel ITT)

  Other third-party libraries:
    Lapack:                      NO
    Eigen:                       YES (ver 3.3.4)
    Custom HAL:                  YES (carotene (ver 0.0.1))
    Protobuf:                    build (3.5.1)

  Python 2:
    Interpreter:                 /usr/bin/python2.7 (ver 2.7.15)
    Libraries:                   /usr/lib/aarch64-linux-gnu/libpython2.7.so (ver 2.7.15+)
    numpy:                       /usr/lib/python2.7/dist-packages/numpy/core/include (ver 1.13.3)
    install path:                lib/python2.7/dist-packages/cv2/python-2.7

  Python 3:
    Interpreter:                 /usr/bin/python3 (ver 3.6.9)
    Libraries:                   /usr/lib/aarch64-linux-gnu/libpython3.6m.so (ver 3.6.9)
    numpy:                       /usr/lib/python3/dist-packages/numpy/core/include (ver 1.13.3)
    install path:                lib/python3.6/dist-packages/cv2/python-3.6

  Python (for build):            /usr/bin/python2.7

  Java:                          
    ant:                         NO
    JNI:                         NO
    Java wrappers:               NO
    Java tests:                  NO

  Install to:                    /usr

The last line says it is installed to /usr. Indeed opencv2 is found in /usr/include/opencv4, so I would expect the libraries to be in /usr/lib, but I can’t find any trace. Where are the libraries and why doesn’t pkg-config know the build flags and libraries for opencv ?

OpenCV 4 does not support pkg-config by default.

TO Activate pkg-config, you can build and install it by yourself.
Add “OPENCV_GENERATE_PKGCONFIG=ON” option while cmake.

Installed OpenCV could be found;
dpkg -L opencv-dev

1 Like

Thanks for that. Any idea where the JetPack install of OpenCV 4 does put it’s library ?

My Jetson nano devkit has R32.4.3 L4T.
And ‘dpkg -L libopencv-dev’ returns as follow;

/usr/lib/aarch64-linux-gnu/libopencv_calib3d.so
/usr/lib/aarch64-linux-gnu/libopencv_core.so
/usr/lib/aarch64-linux-gnu/libopencv_dnn.so

Header files are here;

/usr/include/opencv4/opencv2


modified,

you can run pkg-config command like this;
pkg-config --libs opencv4

@MtHiker thanks, that solved the problem and I found the libraries. I was typing opencv instead of opencv4.