1. A method for automatic calibration, comprising: performing an initial calibration of a catheter, based on internal catheter reflections that are stable in depth and consistent in intensity throughout the 360 degree rotation of the catheter, for a calibration position, the calibration including: averaging an OCT image frame to selectively enhance high intensity features; comparing a value of the image features to a pre-calibrated value; and shifting the OCT image based on the comparison; monitoring the internal catheter reflections of the calibration position; determining if the calibration position needs updating on an image frame; and updating the calibration position on a frame-by-frame basis.