Minimally Invasive Surgery (MIS) with Laparoscopic instruments (LI) has many advantages over traditional procedures, and thus training of laparoscopic instruments via computer simulations has become important. In this study, a method is proposed for 3d pose estimation. For the proposed scheme, a computer vision based training simulator which used a training box composed of a single camera and a planar mirror was developed. This method has advantages over similar literature methods in terms of processing speed and capability of working even with low resolution images. Furthermore, the proposed approach can handle tool occlusions by using the epiline geometry.