Inception V3 on Qualcomm Robotics RB3 DSP

Skill LevelArea of FocusOperating SystemSoftware ToolsPlatform/Hardware
IntermediateComputer Vision, RoboticsLinuxHexagon SDKRobotics RB3 Robotics Dev Kit
This project is designed to show how you can use the Qualcomm® Robotics RB3 development kit, specifically using the Qualcomm® Hexagon™ DSP with Hexagon Vector extensions (HVX), coupled with Hexagon DSP SDK to achieve high speed and high performance on device Machine Learning.

The idea for this project is to use Hexagon DSP in combination with Hexagon SDK to build an optimized multimedia app, while overcoming development hurdles such as lack of battery and insufficient processing power. Additionally, the goal was to build a compelling Image Classification app to showcase on-device Machine Learning, with the ability to offload high computational burdens from the CPU to a heterogeneous computing environment like DSP.

Building the Image Classification application is done in 2 parts.

The first part involves generating Hexagon compatible shared libraries and Inception V3 frozen graph and pushing them to Target robotics development kit.

The second part involves compiling the shared libraries and running the application using OpenCV.

Build Hexagon NN DSP library for the Qualcomm Robotics RB3 CDSP

  • Download the Hexagon SDK version 3.4.2 for Linux from here.
  • Unzip the file and install the SDK using the following commands

    $ cd qualcomm_hexagon_sdk_3_4_2_linux/
    $ chmod +x qualcomm_hexagon_sdk_3_4_2_eval.bin
    $ ./qualcomm_hexagon_sdk_3_4_2_eval.bin
Launch Hexagon SDK Installer

This will pop up a window for the installer, follow the instructions accordingly and complete the installation.

Hexagon SDK Installer window

Note: If you encounter an error “Malformed \uxxxx encoding” like here, change the PS1 prompt and then execute the bin file

  • Set the environment variable $HEXAGON_SDK_ROOT by the command

    $ source /work/Qualcomm/Hexagon_SDK/3.4.2/setup_sdk_env.source
  • Compile Hexagon NN using the following commands and generate a hexagon library

    $ cd $HEXAGON_SDK_ROOT/libs/hexagon_nn/2.5/
    $ make tree VERBOSE=1 CDSP_FLAG=1 V=hexagon_Release_dynamic_toolv82_v65 V65=1
    Build the Hexagon SDK to generate Hexagon nn library
  • The generated here is the shared library for the CDSP

    Build successful, generated

Note: If you get a Hexagon clang error, it is because the Hexagon SDK 3.4.2 has 8.3.02 version of Hexagon Clang instead of 8.2.07. To continue with the build process, Download the Hexagon SDK 3.4.1 for Linux from here and build using all the steps listed till now.

Create a soft link between the 3.4.1 SDK and 3.4.2 SDK , so that Hexagon clang 8.2.07 can be used to build SDK 3.4.2.

Softlink to Hexagon Tools
  • To generate a Testsig, the serial number of Target robotics development kit is needed.
  • Get serial number from the robotics development kit ’s console using command

    $ cat /sys/bus/soc/devices/soc0/serial_number

    If this path is not present in the Target robotics development kit, you may try re-flashing it with one of the new releases, the serial number could be seen during the flashing.

    Serial number obtained during the flashing process
  • Pass the serial_number to using the following commands:

    $ python tools/elfsigner/ -t $SERIAL_NUMBER
  • Sign the shared library using

    $ python tools/elfsigner/ -i
    Pass serial number to and sign the shared library

In this project, you will use an Inception v3 model’s frozen graph for the image classification. In the following steps, download TensorFlow, Bazel and generate a Hexagon DSP compatible version of the Inception V3 frozen graph.

  • Download TensorFlow Inception V3 model Frozen graph using

    $ curl -o /tmp/inceptionv3.tgz and unzip it to /tmp directory.

    $ tar -xzf /tmp/inceptionv3.tgz -C /tmp/ Download inception v3 frozen graph
  • Download and install Bazel (version 0.20.0) using the following commands:

    $ wget
    chmod +x
    $ ./ –-user

    Make sure to add /home/bin to $PATH to avoid bazel not found error.

    Download Bazel Install Bazel and set path
  • Download and build TensorFlow(version 1.13.2) using the following commands

    $ wget
    $ tar -zxvf v1.13.2.tar.gz
    $ cd tensorflow-1.13.2
    $ ./configure
    Download TensorFlow

    To complete the configuration, specify the location of Python and select the appropriate options to build TensorFlow.

    Build TensorFlow
  • Build transform_graph tool in TensorFlow using the following commands

    $ touch WORKSPACE
    $ bazel build tensorflow/tools/graph_transforms:transform_graph

    The build would take a bit longer.

    Build transform_graph tool

    (More information about tranform_graph can be found here)

  • Quantize protobuf using Graph Transform Tool

    $ bazel-bin/tensorflow/tools/graph_transforms/transform_graph --in_graph=/tmp/classify_image_graph_def.pb --out_graph=/tmp/inception_v3_quantized.pb --inputs="Mul" --outputs='softmax' --transforms='add_default_attributes strip_unused_nodes(type=float, shape="1,299,299,3") remove_nodes(op=Identity, op=CheckNumerics) fold_constants(ignore_errors=true) fold_batch_norms fold_old_batch_norms quantize_weights quantize_nodes fold_constants strip_unused_nodes sort_by_execution_order' Quantize Protobuf using graph transform tool
  • Convert the quantized protobuf into a C file (iv3.c) using the following commands

    $ cd $HEXAGON_SDK_ROOT/examples/hexagon_nn/
    $ virtualenv -p python2 env2

    If this gives an error “virtualenv not found”/ “pip missing”, install pip using

    $ sudo apt install python-pip

    and install virtualenv using

    $ sudo apt-get install python-virtualenv)
    $ source env2/bin/activate
    $ pip install -r environments/req2.txt
    installing packages

    Enter the command below to generate Hexagon compatible iv3.c file

    $python $HEXAGON_SDK_ROOT/examples/hexagon_nn/scripts/ /tmp/inception_v3_quantized.pb $HEXAGON_SDK_ROOT/examples/hexagon_nn/tutorials/007-tensorflow-to-hexagon-nn/inceptionv3_v1.yaml > iv3.c

    And copy iv3.c to the folder as shown in the command

    $ cp iv3.c $HEXAGON_SDK_ROOT/libs/hexagon_nn/2.5/ Generate Hexagon compatible Inception V3 graph and copy to Hexagon libs location
  • Navigate to your workspace (Here it is /local/mnt/workspace),

    $ cd /local/mnt/workspace
  • Download the GNU toolchain using the command below and untar it

    $ wget

    $ tar -xf gcc-linaro-7.1.1-2017.08-x86_64_aarch64-linux-gnu.tar.xz

    $ cd Hexagon_SDK/3.4.2/libs/hexagon_nn/2.5/

    $ ln -sf /local/mnt/workspace/gcc-linaro-7.1.1-2017.08-x86_64_aarch64-linux-gnu

    Add the GNU toolchain location to $PATH

    $ export PATH=$PATH:/local/mnt/workspace/gcc-linaro-7.1.1-2017.08-x86_64_aarch64-linux-gnu/bin/

  • Download fastRPC and compile new libraries

    $ git clone -b automake teams/working/qualcomm/fastrpc.git

    $ cd fastrpc
    $ ./

    If you do not have automake already installed, this step gives an error. Install automake with:sudo apt-get install automake

    $ ./configure --host=aarch64-linux-gnu
    $ make

    Copy the shared object files to the location as shown in the commands

    $ cp src/.libs/*
    $ cp src/.libs/*
$ cd $HEXAGON_SDK_ROOT/libs/hexagon_nn/2.5/
  • Download the patch using

    $ wget
  • Patch Hexagon NN with the downloaded patch to compile as shared library for user space

    $ patch -p1
    $ make tree V=UbuntuARM_Debug_aarch64 CDSP_FLAG=1 V65=1 GRAPHINIT="iv3.c"
  • Establish an SSH connection from the host Linux PC to the Target robotics development kit and copy the files into the target using the following commands

    $ ssh linaro@DB_IP_ADDR mkdir /home/linaro/apps /home/linaro/dsp

    $ scp $HEXAGON_SDK_ROOT/output/testsig*.so linaro@DB_IP_ADDR:~/dsp/
    $ scp $HEXAGON_SDK_ROOT/output/ linaro@DB_IP_ADDR:~/dsp/

    $ scp
    $HEXAGON_SDK_ROOT/libs/hexagon_nn/2.5/UbuntuARM_Debug_aarch64/ship/ linaro@DB_IP_ADDR:~/apps/

    $ scp $FASTRPC_LIB_PATH/src/.libs/libcdsp* linaro@DB_IP_ADDR:~/apps/
    $ scp $FASTRPC_LIB_PATH/src/.libs/libadsp* linaro@DB_IP_ADDR:~/apps/
    $ scp $FASTRPC_LIB_PATH/src/.libs/*rpcd linaro@DB_IP_ADDR:~/apps/

Once the files are pushed to the Target, you do not need to use the host PC anymore.

Step 1: Make hardware connections and power up Robotics Development Kit, set the Screen to avoid blanking

  • Connect Robotics Development Kit with USB Camera on the right most port, and wireless USB for Keyboard and mouse on the other port.
  • Connect Robotics Development Kit with HDMI cable and the other end of the cable to the HDMI Screen/monitor that is powered on.
  • Connect the power cable to Robotics Development Kit and wait for the desktop to pop up.

    Connections to RB3
  • Open a terminal by navigating to System Tools > QTerminal as shown below

    Open Terminal
  • Change the screen properties using the commands below, to avoid blanking of screen after a short period of inactivity on the board.

    $ xset s off
    $ xset dpms 0 0 0
    $ xset dpms s off

Step 2: Install fastrpc lib on Target Qualcomm Robotics Development Kit

  • In the terminal, login as sudo and check if there are any old adsprpc libraries and remove them

    $ sudo su
    $ rm /usr/local/libadsp* /usr/local/libcdsp* /usr/local/bin/cdsprpcd /usr/local/bin/adsprpcd
  • Copy the fastRPC libs to /usr/local/lib and /usr/local/bin

    $ cp /home/linaro/apps/libcdsp* /usr/local/lib/
    $ cp /home/linaro/apps/libadsp* /usr/local/lib/
    $ cp /home/linaro/apps/*rpcd /usr/local/bin

Step 3: Mount the dsp and start cdsprpcd daemon

  • $ mkdir /dsp
    $ mount /dev/disk/by-partlabel/dsp_a /dsp
    $ cp /home/linaro/dsp/* /dsp/cdsp/
    $ export ADSP_LIBRARY_PATH=/dsp/cdsp
    $ export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/lib
    $ cdsprpcd&
    Run cdsprpcd daemon

Step 4: Install OpenCV on the Target

  • In another terminal, type in the following commands to download and install OpenCV

    $ git clone
    $ cd ~/opencv
    $ mkdir build
    $ cd build
    $ cmake -D CMAKE_BUILD_TYPE=Release -D

    (If this gives an error “cmake not installed”, install cmake with

    apt-get -y install cmake)
    $ make -j8
    $ sudo make install

Step 5: Run OpenCV ImageNet application for camera

  • Download the application from the camera branch and build using the following commands

    $ git clone
    $ cd ImagenetCv
    download and checkout the camera branch

    Build application using

    $ cmake .
    $ make

    Run the application using the command $ ./ImagenetCv

    If this shows an error like “install libgtk2.0-dev”

    Install libgtk2.0-dev using the commands given below and run the application

    $ apt get update
    $ apt get upgrade
    $ apt get install libgtk2.0-dev

    Running the application pops up a window that shows video captured by the camera and the image classification being done

    Live image classification window

Step 6: Run OpenCV ImageNet application for local Images

  • Download the application from the images branch and build using the following commands
  • $ git clone
    $ cd ImagenetCv
    $ cmake .
    $ make
    $ ./ImagenetCv

    4 windows pop up, that show image classification being done on local images.

    Image Classification on local test images and live images captured by camera

Qualcomm Robotics and Qualcomm Hexagon are products of Qualcomm Technologies, Inc. and/or its subsidiaries.

Srinivas KandagatlaLinaro
Ramya K PolisettiQualcomm