IMAGE PROCESSING METHOD AND X-RAY APPARATUS HAVING IMAGE PROCESSING MEANS FOR EXTRACTING A THREAD-LIKE STRUCTURE IN A NOISY DIGITAL IMAGE

An image processing method and an X-ray apparatus in which a thread-like structure represented on the background in a noisy digital original image is extracted. Original image data is acquired and reduced using a transformation operation so as to provide a reduced image. The most probable locations of guide-wire points in the reduced image are selected by selecting at each point the direction of the guide-wire which provides the best match with one of several predetermined regularly oriented directions and by probing the contrast around and in the selected directions and then probing the contrast around selected locations in the original image corresponding to the selected location of points in the reduced image. Then, the points which satisfy a contrast condition are extracted and the points which also satisfy a connectivity criterion in the reduced image are connected and these points are extracted as guide-wire points of the original image.