intro_yolo_fix.md

Introduction to YOLO - Fix

Prerequisites

• This is based on Intelligent Quads' work. Clone the repo from here. Below tutorial is a prerequisite:
  • Using MAVROS to Get Telemetry Data - Fix
• Then, follow Introduction to YOLO/Darknet Image Recognition. Continue with the video tutorial.

Problem and Fix

When running roslaunch darknet_ros darknet_ros.launch, you may encounter with a problem due to building Darknet incorrectly. This causes camera window to not open. To fix,

#For Ubuntu 20. For 18, change clone git addresses.

#If you did not clone the repo already, follow the below code block
cd ~/catkin_ws/src
git clone https://github.com/kunaltyagi/darknet_ros.git
cd darknet_ros
git checkout opencv4
git submodule update --init --recursive
catkin build -DCMAKE_BUILD_TYPE=Release -DCMAKE_C_COMPILER=/usr/bin/gcc-8

#Remove darknet_ros folder
rm -r -f darknet_ros

#Reclone the repo and build again without DCMAKE_C_COMPILER flag
git clone https://github.com/kunaltyagi/darknet_ros.git 
cd darknet_ros
git checkout opencv4
git submodule update --init --recursive
catkin build -DCMAKE_BUILD_TYPE=Release 

Run the simulation environment as told in the tutorial video.