You need to get an instance of an AxisCamera before you can call that method.
Example:
Code:
// Typically you only want to do this ONCE; camera should be a class member
AxisCamera camera = AxisCamera.getInstance();
// Then you can get the image as often as you would like (but it's pretty slow, you don't want to call this more than once per 50 milliseconds or so!
ColorImage image = camera.getImage();