Patent ID: 8542895

Claim:
An image processing method for calculating blood vessel direction of a flow velocity image comprising a plurality of point-regions, each point-region associated with a central point, the method comprising: distinguishing each of the point-regions in the flow velocity image as point-regions in a flow region and point-regions in a background region; estimating a rough direction of a computing point-region by: setting a plurality of directions and respectively calculating the number of point-regions in the flow region connecting with the computing point-region in each direction; and taking the direction with the maximum number of point-regions as the rough direction of the computing point-region; determining middle point-regions on the direction perpendicular to the rough direction in a neighborhood; determining a line connecting the central points of the middle point-regions as a median line of the blood vessel in the neighborhood, wherein the neighborhood is centered on the computing point-region and includes a plurality of point-regions in the flow region in the rough direction; and calculating the direction of the blood vessel on the computing point-region according to the determined median line of the blood vessel, wherein calculating comprises applying a linear fitting or Hough Transform to the determined median line of the blood vessel.