How to eliminate background in rgb/grayscale so when I convert to binary it wont interfere with my image.

This is the image I am working with: http://imgur.com/8qTnyGq

I am trying to eliminate the background of this image so only the crosshairs, the ball, and the rod remain.

Like this: http://imgur.com/LG3NZTt

In the end I was hoping to have a binary image. I have tried some of the techniques associated with bwmorph and imopen, but none have really helped so far. Perhaps I have overlooked something? Any advice would be greatly appreciated :)