1. A method for providing a patient registration without fiducials or manual intervention, by a device containing a processor and a memory, comprising the steps of: generating a binary preoperative image from a grayscale preoperative image of a patient; generating a binary intraoperative image from a grayscale intraoperative image of the patient; generating multiple different random starting registration positions of the binary intraoperative image relative to the binary preoperative image; performing a first batch of registrations of the binary intraoperative image with the binary preoperative image, wherein the first batch of registrations comprises multiple registrations each corresponding to one random starting registration position of the multiple different random starting registration positions; converging information from the first batch of registrations to generate a new starting registration position; executing a second registration between the grayscale preoperative image and the grayscale intraoperative image from the new starting registration position; and computing the patient registration directly from the second registration, wherein the new starting registration position is the only starting registration position for the second registration, and the first batch of registrations and the second registration do not involve user guidance.