Image isolation from back ground

Design details: We have an engraving of an instrument that we want separating from its cream coloured paper background. What we want is to use the image with any given coloured background so the image must have a transparent background. The image needs to be all one colour and thickness. It will also need tweaking back to (as near as possible) square as the frame is distorted.

Uploaded image is the actual image
Ideas for the visual style: Simple single colour
Extra notes: