ballboy

Detects a ball within a given HSV range and outputs its coordinates to stdout.

Requirements

• a webcam
• a coloured ball
• OpenCV

To build

Install OpenCV:

# OSX
brew install opencv

# CentOS
yum install opencv

# Debian
apt-get install opencv

Clone and compile ballboy:

git clone https://github.com/siadat/ballboy
cd ballboy
cmake .
make

To run

# See usage:
./ballboy

# Run it for a green ball with HSV between (78,41,75) and (91, 256, 204):
./ballboy 78 41 75 91 256 204

# Run it with theremin midi controller:
./ballboy 66 47 24 90 256 204 | ruby ./examples/theremin.rb

# Run in verbose mode (extra lines are prefixed with '#')
./ballboy -v 66 47 24 90 256 204

The output looks like this:

x:36    y:55    r:31
x:38    y:62    r:30
x:40    y:65    r:32
x:40    y:60    r:31
x:35    y:50    r:29

All values are normalized between 0 and 100. If nothing is found, the values will be -1.