You need to install
http://firstforge.wpi.edu/sf/frs/do/.../frs.installer
And then import everything under
C:\Program Files\SmartDashboard
and
C:\Program Files\SmartDashboard\extensions
and
C:\Program Files\SmartDashboard\extensions\lib
into your Java Class Library (a type of project you can start in Netbeans)
You will want to have your extension class extend WPICameraExtension.
You will also want to override the method processImage, as sretter has said.