1. A system for object tracking, comprising: at least one processor configured to act as a tracker configured to: receive real time images from time t 0 , at least for tracking an object in said real time images, determine a first reference image of the tracked object, track the object in at least real time images received after time t 0 based at least partly on the first reference image, provide the first reference image to an output interface, so that the operator can view, during the tracking, each of said real time images received after time t 0 at the same time as the first reference image, perform at least steps (S1 i ), (S2 i ) and (S3 i ) for i=1: (S1 i ) at time t i , perform an update to a new reference image which is calculated based on at least two of the real time images received from time t i-1 to time t i , wherein the tracked object as appearing in the new reference image is not identical to the tracked object as appearing in any of the real time images received from time t i-1 to time t i , (S2 i ) track the object in at least a plurality of real time images received after time t i , based at least partly on the new reference image, (S3 i ) provide the new reference image to an output interface, so that the operator can view each real time image of said plurality of real time images received after time t i at the same time as the new reference image, and repeat at least once steps (S1 i ), (S2 i ) and (S3 i ), wherein the value of i is incremented by one at each repetition.