Disclosed is a system and method for computing out of plane motion between two ultrasound images. The method identifies regions of fully developed speckle that are common to the two images, computes a correlation coefficient corresponding to the two fully developed speckle image regions, and then computing an elevation distance corresponding to the correlation coefficient. The method exploits the measurable and characterizable relation between inter-image correlation and elevation distance, which may be determined from fully developed speckle regions. The method also identifies regions within the ultrasound images related to structure (e.g., vein or bone), and disregards these regions.