Systems and methods for assisting with internal positioning of instruments

An imaging system comprising:

• an imaging transducer operable to receive signals for creating an image of an object during performance of a procedure;
• an instrument guide coupled to the imaging transducer, the instrument guide operable to provide guidance for movement of an instrument during performance of the procedure;
• and
• an opto-mechanical sensor system disposed on the instrument guide, the opto-mechanical sensor system including:
• a rotatable interface surface positioned on an axel having a first diameter;
• a spring that biases the axel of the rotatable interface surface toward the instrument;
• an encoded sensor surface coupled to the rotatable interface surface, wherein the encoded sensor surface has a second diameter that is larger than the first diameter;
• and
• a light source and optical detector positioned on opposite sides of the encoded sensor surface;
• wherein the rotatable interface surface is arranged to be biased by the spring against an instrument that is positioned between the instrument guide and the rotatable interface surface such that movement of the instrument with respect to the instrument guide rotates the encoded sensor surface between the light source and the optical detector and an arc of rotation of an outer axel of the encoded sensor surface is larger than an arc of rotation of the axel of the interface surface, thereby multiplying the magnitude of the motion of the instrument, and
• wherein the opto-mechanical sensor system is operable to provide instrument movement information regarding movement of the instrument during performance of the procedure.