A surgical instrument assembly for minimal invasive surgery comprising a surgical instrument and a pattern generating member, the surgical instrument has a distal end and a proximal end and comprises a surgical tool adapted for performing a surgical intervention at its distal end. The pattern generating member comprises a pattern light source and a projector adapted for projecting a light pattern. At least the projector is at least temporarily fixed to a body portion of the surgical instrument connecting the surgical tool to the proximal end, such that a movement of the surgical tool results in a correlated movement of the projector.
