Brokerless ZeroMq to share live image/video data stream from Raspberry PI B+ (Uses OpenCV)

Makes sure you have the following :

  1. OpenCV 3.x compiled and installed on Rasbperry Pi
  2. Raspberry Pi B+ with Raspbian and a USB webcam attached

ZeroMQ

Read through ZeroMQ in 100 words for a brief description

zmq

Installationhttp://zeromq.org/bindings:python

 

Code

Now lets go through the simple code I wrote for publishing and subscribing to live webcam stream from a raspberry PI to a workstation.

 

Make sure you have the dependencies and imports as below

import os, sys, datetime
import json, base64

import cv2
import zmq
import numpy as np
import imutils
from imutils.video import FPS

 

“”” Publish “””

  • In this piece of code we are creating a Zero MQ context preparing to send data to ‘tcp://localhost:5555’
  • The opencv API for camera is used to capture a frame from the device in 640×480 size
  • FPS module is used from opencv to estimate the frame rate for this capture
  • The byte buffer read from the webcam is encoded and sent as a string over the Zero MQ TCP socket connection
  • Continue to send each buffer out on the TCP socket
def pubVideo(config):
    context = zmq.Context()
    footage_socket = context.socket(zmq.PUB)
    # 'tcp://localhost:5555'
    ip = "127.0.0.1"
    port = 5555
    target_address = "tcp://{}:{}".format(ip, port) 
    print("Publish Video to ", target_address)
    footage_socket.connect(target_address)
    impath = 0 # For the first USB camera attached
    camera = cv2.VideoCapture(impath)  # init the camera
    camera.set(cv2.CAP_PROP_FRAME_WIDTH, 640)
    camera.set(cv2.CAP_PROP_FRAME_HEIGHT, 480)
    print("Start Time: ", datetime.datetime.now())
    fps = FPS().start()
    while True:
        try:
            buffer = capture(config, camera)
            if not isinstance(buffer, (list, tuple, np.ndarray)):
                break
            buffer_encoded = base64.b64encode(buffer)
            footage_socket.send_string(buffer_encoded.decode('ascii'))
            # Update the FPS counter
            fps.update()
            cv2.waitKey(1)
        except KeyboardInterrupt:
            # stop the timer and display FPS information
            fps.stop()
            print("[INFO] elasped time: {:.2f}".format(fps.elapsed()))
            print("[INFO] approx. FPS: {:.2f}".format(fps.fps()))
            camera.release()
            cv2.destroyAllWindows()
            print("\n\nBye bye\n")
            break
    print("End Time: ", datetime.datetime.now())

 

“”” Subscribe “””

  • The ZeroMQ subscriber is listening on ‘tcp://*:5555’ 
  • As the string is received its decoded and converted to image using OpenCv
  • We use OpenCV to visualize this frame in a window
  • Every frame sent over the ZeroMQ TCP socket is visualized and appears as a live video stream
def subVideo(config):
    context = zmq.Context()
    footage_socket = context.socket(zmq.SUB)
    port = 5555
    bind_address = "tcp://*:{}".format(port) # 'tcp://*:5555'
    print("Subscribe Video at ", bind_address)
    footage_socket.bind(bind_address)
    footage_socket.setsockopt_string(zmq.SUBSCRIBE, str(''))
    while True:
        try:
            frame = footage_socket.recv_string()
            img = base64.b64decode(frame)
            npimg = np.fromstring(img, dtype=np.uint8)
            source = cv2.imdecode(npimg, 1)
            cv2.imshow("image", source)
            cv2.waitKey(1)
        except KeyboardInterrupt:
            cv2.destroyAllWindows()
            print("\n\nBye bye\n")
            break

Github: https://github.com/vishwakarmarhl/cnaviz/blob/master/imcol/CvZmq.py

 

Run

In the github code above, you can run the test as follows,

PUB: Webcam source machine

python CvZmq.py pub --pubip=127.0.0.1 --pubport=5555

SUB: Target visualization machine

python CvZmq.py sub --subport=5555

 

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Compile and Setup OpenCV 3.4.x on Ubuntu 18.04 LTS with Python Virtualenv for Image processing with Ceres, VTK, PCL

OpenCV: Open Source Computer Vision Library

Links

Documentation: https://docs.opencv.org/3.4.2/

OpenCV Source: https://github.com/opencv/opencv

OpenCV_Logo

A. Setup an external HDD/SSD for this setup

filesystem-partition-ubuntu-external-ssd

B. Environment (Ubuntu 18.04 LTS)

 

Python3 setup

Install the needed packages in a python virtualenv. Refer similar windows Anaconda setup or look at the ubuntu based info here

sudo apt-get install -y build-essential cmake unzip pkg-config 
sudo apt-get install -y ubuntu-restricted-extras
sudo apt-get install -y python3-dev python3-numpy
sudo apt-get install -y git python3-pip virtualenv
sudo pip3 install virtualenv
rahul@karma:~$ virtualenv -p /usr/bin/python3 cv3
Already using interpreter /usr/bin/python3
Using base prefix '/usr'
New python executable in /home/rahul/cv3/bin/python3
Also creating executable in /home/rahul/cv3/bin/python
Installing setuptools, pkg_resources, pip, wheel...
done.

Activate and Deactivate the python Environment

rahul@karma:~$ source ~/cv3/bin/activate
(cv3) rahul@karma:~$ python
Python 3.6.5 (default, Apr 1 2018, 05:46:30) 
[GCC 7.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> print("Test",4*5)
Test 20
>>> exit()
(cv3) rahul@karma:~$ deactivate
rahul@karma:~$ 

Alternatively, a great way to use virtualenv is to use Virtualenvwrappers

sudo pip3 install virtualenv virtualenvwrapper

Add these to your ~/.bashrc file

# virtualenv and virtualenvwrapper
export WORKON_HOME=$HOME/.virtualenvs
export VIRTUALENVWRAPPER_PYTHON=/usr/bin/python3
source /usr/local/bin/virtualenvwrapper.sh

Now, run “source ~/.bashrc” to set the environment

Create a Virtual environment
rahul@karma:~$ mkvirtualenv cv3 -p python3
Already using interpreter /usr/bin/python3
Using base prefix '/usr'
New python executable in /home/rahul/.virtualenvs/cv3/bin/python3
Also creating executable in /home/rahul/.virtualenvs/cv3/bin/python
Installing setuptools, pkg_resources, pip, wheel...done.
virtualenvwrapper.user_scripts creating /home/rahul/.virtualenvs/cv3/bin/predeactivate
virtualenvwrapper.user_scripts creating /home/rahul/.virtualenvs/cv3/bin/postdeactivate
virtualenvwrapper.user_scripts creating /home/rahul/.virtualenvs/cv3/bin/preactivate
virtualenvwrapper.user_scripts creating /home/rahul/.virtualenvs/cv3/bin/postactivate
virtualenvwrapper.user_scripts creating /home/rahul/.virtualenvs/cv3/bin/get_env_details
(cv3) rahul@karma:~$
Activate/Deactivate virtual env
rahul@karma:~$ workon cv3
(cv3) rahul@karma:~$ deactivate 
rahul@karma:~$

Install basic packages for the computer vision work.

(cv3) rahul@karma: pip install numpy scipy scikit-image scikit-learn  
pip install imutils pyzmq ipython matplotlib
pip install dronekit==2.9.1 future==0.15.2 monotonic==1.2 pymavlink==2.0.6

Java installation from this blog

sudo add-apt-repository ppa:linuxuprising/java
sudo apt update
sudo apt install oracle-java10-installer
sudo apt install oracle-java10-set-default sudo apt-get install ant
Packages needed for OpenCV and others
GTK support for GUI features, Camera support (libv4l), Media Support (ffmpeg, gstreamer) etc. Additional packages for image formats mostly downloaded form the ubuntu-restricted-extra repository

 

sudo apt-get install -y libjpeg-dev libpng-dev libtiff-dev ffmpeg
sudo apt-get install -y libjpeg8-dev libjasper-dev libpng12-dev libtiff5-dev
sudo apt-get install -y libavcodec-dev libavformat-dev libswscale-dev libv4l-dev
sudo apt-get install -y libxvidcore-dev libx264-dev libvorbis-dev
sudo apt-get install -y libgtk2.0-dev libgtk-3-dev ccache imagemagick
sudo apt-get install -y liblept5 leptonica-progs libleptonica-dev
sudo apt-get install -y qt5-default libgtk2.0-dev libtbb-dev
sudo apt-get install -y libatlas-base-dev gfortran libblas-dev liblapack-dev 
sudo apt-get install -y libdvd-pkg libgstreamer-plugins-base1.0-dev
sudo apt-get install -y libmp3lame-dev libtheora-dev
sudo apt-get install -y libxine2-dev libv4l-dev x264 v4l-utils
sudo apt-get install -y libopencore-amrnb-dev libopencore-amrwb-dev

# Optional dependencies
sudo apt-get install -y libprotobuf-dev protobuf-compiler
sudo apt-get install -y libgoogle-glog-dev libgflags-dev
sudo apt-get install -y libgphoto2-dev libeigen3-dev libhdf5-dev doxygen

 

VTK for SFM Modules

SFM setup: https://docs.opencv.org/3.4.2/db/db8/tutorial_sfm_installation.html

sudo apt-get install libxt-dev libglew-dev libsuitesparse-dev
sudo apt-get install tk8.5 tcl8.5 tcl8.5-dev tcl-dev

Ceres-Solver: http://ceres-solver.org/installation.html

# However, if you want to build Ceres as a *shared* library, 
# You must, add the following PPA:
sudo add-apt-repository ppa:bzindovic/suitesparse-bugfix-1319687
sudo apt-get update
sudo apt-get install libsuitesparse-dev
git clone https://ceres-solver.googlesource.com/ceres-solver
cd ceres-solver
mkdir build && cd build
export CXXFLAGS="-std=c++11" 
cmake ..
make -j4
make test
sudo make install

LAPACK

sudo apt-get install libblas-dev libblas-doc liblapacke-dev liblapack-doc

 

VTK Setup, https://gitlab.kitware.com/vtk/vtk.git

Configure and build with QT support

git clone git://vtk.org/VTK.git VTK
cd VTK
mkdir VTK-build
cd VTK-build
CXXFLAGS="-std=c++11" cmake ../ -DBUILD_SHARED_LIBS=ON -DBUILD_TESTING=ON \
-DCMAKE_BUILD_TYPE=Release \
-DQT_QMAKE_EXECUTABLE:PATH=/usr/bin/qmake \
-DVTK_Group_Qt:BOOL=ON \
-DBUILD_SHARED_LIBS:BOOL=ON \
-DVTK_WRAP_PYTHON=ON  \
-DPYTHON_EXECUTABLE=~/.virtualenvs/cv3/bin/python 
make -j4
sudo make install
$ cp -r ~/cv/VTK/VTK-build/lib/python3.6/site-packages/* ~/.virtualenvs/cv3/lib/python3.6/site-packages/
$ export LD_LIBRARY_PATH="$LD_LIBRARY_PATH:/usr/lib:/usr/local/lib"
$ sudo ldconfig

FLANN

http://www.cs.ubc.ca/research/flann/#download
cd flann-1.8.4-src/ && mkdir build && cd build
cmake ..
make -j4 
sudo make install

PCL

Download: http://www.pointclouds.org/downloads/linux.html

sudo apt-get install -y libusb-1.0-0-dev libusb-dev libudev-dev
sudo apt-get install -y mpi-default-dev openmpi-bin openmpi-common 
sudo apt-get install -y libboost-all-dev libpcap-dev  sudo apt-get install -y libqhull* libgtest-dev sudo apt-get install -y freeglut3-dev pkg-config sudo apt-get install -y libxmu-dev libxi-dev sudo apt-get install -y mono-complete sudo apt-get install -y openjdk-8-jdk openjdk-8-jre
git clone https://github.com/PointCloudLibrary/pcl 
# https://github.com/PointCloudLibrary/pcl/archive/pcl-1.8.1.tar.gz 
cd pcl && mkdir build && cd build 
CXXFLAGS="-std=gnu++11" cmake -DBUILD_apps=ON \
 -DBUILD_apps_point_cloud_editor=ON \
 -DBUILD_apps_cloud_composer=ON \
 -DBUILD_apps_modeler=ON \
 -DBUILD_apps_3d_rec_framework=ON \
 -DBUILD_examples=ON ..
make -j8 
sudo make install

Official OpenCV installation

wget -O opencv.zip https://github.com/opencv/opencv/archive/3.4.2.zip
wget -O opencv_contrib.zip https://github.com/opencv/opencv_contrib/archive/3.4.2.zip
unzip opencv.zip
unzip opencv_contrib.zip

In case of Raspberry PI 3 B+, this blog worked for me.

Link: https://www.pyimagesearch.com/2016/04/18/install-guide-raspberry-pi-3-raspbian-jessie-opencv-3/

 

Configure OpenCV with CMake
$ cd ~/cv/opencv-3.4.2 && mkdir build && cd build
$ CXXFLAGS="-std=c++11" cmake -D CMAKE_BUILD_TYPE=RELEASE \
-D CMAKE_INSTALL_PREFIX=/usr/local \
-D INSTALL_PYTHON_EXAMPLES=ON \
-D INSTALL_C_EXAMPLES=OFF \
-D BUILD_opencv_java=OFF \
-D OPENCV_EXTRA_MODULES_PATH=~/cv/opencv_contrib-3.4.2/modules \
-D WITH_TBB=ON \
-D WITH_V4L=ON \
-D WITH_QT=ON \
-D WITH_OPENGL=ON \
-D WITH_VTK=ON \
-D WITH_GTK3=ON \
-D PYTHON_EXECUTABLE=~/.virtualenvs/cv3/bin/python \
-D BUILD_EXAMPLES=ON ..
Screenshot from 2018-07-12 13-18-55

Make sure the Python 3 interpreter and other dependencies are configured correctly.

Compiling with CUDA (Setup instructions)

cmake -D CMAKE_BUILD_TYPE=RELEASE \
-D CMAKE_INSTALL_PREFIX=/usr/local \
-D INSTALL_PYTHON_EXAMPLES=ON \
-D INSTALL_C_EXAMPLES=ON \
-D BUILD_NEW_PYTHON_SUPPORT=ON \
-D OPENCV_EXTRA_MODULES_PATH=~/cv/opencv_contrib-3.4.2/modules \
-D WITH_TBB=ON \
-D WITH_V4L=ON \
-D WITH_QT=ON \
-D WITH_OPENGL=ON \
-D WITH_VTK=ON \
-D WITH_GTK3=ON \
-D PYTHON_EXECUTABLE=~/.virtualenvs/cv3/bin/python \
-D WITH_CUDA=ON \
-D ENABLE_FAST_MATH=1 \
-D CUDA_FAST_MATH=1 \
-D WITH_CUBLAS=1 \
-D BUILD_EXAMPLES=ON ..

 

Compile, Install and Verify
(cv3) rahul@karma:~/cv/opencv-3.4.2/build$ make -j4
$ sudo make install
$ sudo sh -c 'echo "/usr/local/lib" >> /etc/ld.so.conf.d/opencv.conf'
$ sudo ldconfig
$ pkg-config --modversion opencv
Setup the cv shared libraries
(cv3) rahul@karma$ ls -l /usr/local/lib/python3.6/site-packages
total 5172
-rw-r--r-- 1 root staff 5292240 Jul 12 13:32 cv2.cpython-36m-x86_64-linux-gnu.so
# or use the find command 
$ find /usr/local/lib/ -type f -name "cv2*.so"
$ cd /usr/local/lib/python3.6/site-packages/
$ mv cv2.cpython-36m-x86_64-linux-gnu.so cv2.so
$ cd ~/.virtualenvs/cv3/lib/python3.6/site-packages/
$ ln -s /usr/local/lib/python3.6/site-packages/cv2.so cv2.so

C. Test

(cv3) rahul@karma:~$ python
Python 3.6.5 (default, Apr 1 2018, 05:46:30) 
[GCC 7.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information
>>> import cv2
>>> cv2.__version__
'3.4.2'
>>> exit()
(cv3) rahul@karma:~$

Done.