Abstract: A method for forming an assembled image from successive sub-images comprises the step of acquiring the sub-images, notably X-ray images, with an X-ray detector comprising an essentially flat X-ray-sensitive surface. An X-ray examination apparatus comprises an X-ray detector having a flat X-ray sensitive surface. Advantageously, difference images are derived from successive sub-images. For example, the assembled image derived from the difference images is used to display blood flow patterns in a patient's vascular system.

Abstract: Sub-images are merged in order to form an assembled image representing an elongate scene. In order to counteract artifacts in the assembled image such as disturbing transitions at the boundaries of adjacent sub-images in the image assembly method in accordance with the invention, pixel-values of overlapping portions of consecutive sub-images are interpolated so as to form pixel-values of the assembled image. The relative shift between consecutive sub-images with respect to the elongate scene is calculated from image information contained in the sub-images themselves. Correlations of pixel-values in overlapping portions of consecutive sub-images are determined as a function of the shift-value of the shift between consecutive sub-images with respect to the elongate scene. The actual shift between consecutive sub-images is found as the shift-value for which the correlation attains its maximum-value.

Abstract: Sub-images of an e.g. elongate scene are merged so as to form combined first and second portions on the basis of individual shifts of successive sub-images relative to the elongate scene. The first combined portion is distorted, notably compressed or expanded, on the basis of the dimensions of the first and second combined portions. The distorted first combined portion is merged with the combined second portion so as to form the composite image. The sub-images are formed, for example by irradiating a patient by means of an X-ray beam in different positions. For example, the distorted combined first portion shows a scale graduation and the combined second portion contains anatomic information of a patient.

Abstract: An image processing method is provided to remove areas from an image made by x-irradiation, said areas corresponding to absorption filters in the x-ray beam. Because such filters, also known as x-ray shutters, are inserted into the x-ray beam from the outside of the x-ray beam, x-ray shutter-areas extend from the periphery of the image. Therefore, once the edge of an x-ray shutter-areas has been determined, the part of the image located between the periphery and the x-ray shutter-edge is removed. X-ray shutter-edges are determined by locating transition-points in the image having brightness-transitions having maxima of both the first and second spatial derivatives of the brightness-value. An x-ray shutter-edge is then determined by fitting a curve through the transition-points. The curve fitting is performed with the use of weight-factors that are representative of the likelihood that a transition-point is on an actual x-ray shutter-edge.