Digital image processing method for automatic extraction of strip-shaped objects

A medical system for the processing of digital medical images representing strip-shaped objects on a background comprising:

• a system for the acquisition of a digital image,
• an image processing system comprising a microprocessor having access to the data of an acquired digital image and for automatically extracting substantially strip-shaped objects from the acquired digital image by skeletonizing objects in the image, and
• a system for the display of the images acquired by the acquisition system and the images processed by the image processing system,
• wherein the image processing system is further configured for skeletonizing objects by performing the steps of
• 1) forming, smoothed images at several scales from the digital image, and, in each smoothed image:
• 2) extracting boundary pixels of objects,
• 3) extracting potential median pixels associated with a location of a center of a circle having a radius which is linked to the scale by a proportionality constant, tangent to boundaries at a pair of distinct boundary pixels, and associated with a measure of dependability that the center of the circle and the boundary pixels of the pair are substantially aligned,
• 4) extracting median pixels by way of a first selection of potential median pixels extracted from different smoothed images which have the maximum measure of dependability for the same location, and by way of a second selection of remaining potential median pixels which locally have a maximum intensity substantially in the direction of alignment, and, in a digital image formed by extracted median pixels:
• 5) tracking extracted median pixels in order to construct skeletons of objects.