Imaging system and method for use in surgical and interventional medical procedures

An image processing apparatus for generating a display of an image of a patient's internal anatomy during a medical procedure, comprising:

• a memory for storing a high resolution baseline image of the surgical field including the patient's internal anatomy in a baseline orientation and a new image of the surgical field at a low resolution, wherein the high resolution baseline image is a digitally reconstructed radiograph from a computed tomography scan image;
• and
• a processor configured to:
• digitally manipulate the high resolution baseline image to produce a baseline image set including representative images of the baseline image at a plurality of permutations of movements of the baseline image from the baseline orientation, wherein the permutations of movements includes movements in six degrees of freedom corresponding to a three-dimensional image;
• perform software instructions for comparing the new image to the representative images in the baseline image set and selecting the representative image having an acceptable degree of correlation with the new image;
• digitally merging the selected representative image with the new image;
• and
• generating signals for displaying the merged image on a display device.