Abstract: The invention relates to the association of a current (X-ray image) image of a body volume with one of several stored previous images, the ECG and the respiratory cycle being determined each time together with the images. Using this data, that one of the previous images is chosen which is closest to the current image in respect of cardiac rhythm and respiratory cycle. The resultant association yields a very high accuracy enabling superposed reproduction of the current image and the associated previous image.

Abstract: The invention relates to a method of determining the position of an object in an (X-ray) image (1). A pattern of marking elements is attached to the object., wherein the marking elements are not visibly evident individually in the image (I), i.e. they form an invisible “watermark”. By means of a correlation between the image (I) and a filter image (M) of the pattern of marking elements, however, the position of the marking elements, and thereby that of the object, can be localized in the image (I).

Abstract: The invention relates to a method of multi-resolution with gradient-adaptive filtering (MRGAF) of X-ray images in real time. For an image strip of 2K adjacent rows, a resolution into a Laplacian pyramid (L0, . . . L3) and a Gaussian pyramid (G0, . . . G3) is carried out up to the K-th stage. By limiting a processing operation to such a strip, it is possible to keep all relevant data ready in a local memory with rapid access (cache). A further acceleration compared to the conventional algorithm is achieved by calculating the gradient (D) from the Gaussian pyramid representations. By virtue of these and other optimization measures, it is possible to increase a multi-resolution with gradient-adaptive filtering to a processing rate of more than thirty (768 (E 564) images per second.

Abstract: The invention relates to an X-ray examination apparatus and a method for forming an X-ray image by means of a processing unit (2) for the correction of image data. In order to achieve automatic correction of imaging defects that are caused by imperfections in the imaging and processing chain, the processing unit (2) is succeeded by a defect detection unit (3) for the detection of image defects that can be detected on the basis of image parameters that can be extracted from image data acquired during clinical examinations, and is suitable for adapting processing parameters (15–21) that are used in the processing unit (2) in dependence on the detected image defects.

Abstract: The invention relates to a method of and a device for forming an image which is composed of a plurality of sub-areas, a read-out unit being associated with each sub-area and image data of adjoining image areas of neighboring sub-areas being evaluated in order to mitigate differences in amplification, which device includes a detector with a plurality of sensor elements for forming image data, read-out units which are associated with the sub-areas of the image, an analysis unit which is arranged to evaluate image data from adjoining image areas of neighboring sub-areas and to generate correction data, a correction unit which is arranged to correct incorrect image data by means of correction data, thus enabling a regular and accurate recalibration or correction of non-linear amplifier behavior to be performed without necessitating an additional X-ray dose or interventions by the user.

Abstract: The invention relates to a method of and a device for forming an image which is composed of a plurality of sub-areas, a read-out unit being associated with each sub-area and image data of adjoining image areas of neighboring sub-areas being evaluated in order to mitigate differences in amplification, which device includes a detector with a plurality of sensor elements for forming image data, read-out units which are associated with the sub-areas of the image, an analysis unit which is arranged to evaluate image data from adjoining image areas of neighboring sub-areas and to generate correction data, a correction unit which is arranged to correct incorrect image data by means of correction data, thus enabling a regular and accurate recalibration or correction of non-linear amplifier behavior to be performed without necessitating an additional X-ray dose or interventions by the user.

Abstract: The invention relates to a method and a device for automatic testing of an X-ray system (2). The doors (5a, 5b) leading to the room (1) in which the X-ray system (2) is installed are monitored by way of sensors (4a, 4b). Furthermore, the state of the room (1) can be monitored by means of further sensors such as video cameras (3). Automatic testing of the X-ray system (2) while utilizing X-rays is started only if and for as long as all doors are closed and the other sensors do not indicate that a safe state is abandoned. The device may also include facilities for automatically positioning a phantom in the beam path. Such facilities may in that case include a phantom which is provided on a flexible foil.

Abstract: The invention relates to a method of determining a corresponding image of a moving object for a reference image from an image sequence which represents the motion as a sequence of states of motion. To this end, two motion signals, representing the development of the relevant motions, are examined for similarities. Using the similarity function thus obtained, that image in the image sequence can be determined which represents at least approximately the state of motion of the object which is represented in the reference image. Furthermore, the invention relates to a system which is suitable for carrying out the method as well as to a computer program and a computer program product enabling a data processing unit to carry out the method.

Abstract: The invention relates to a method for the calibration of a radiation sensor, in which method a first calibration takes place with external radiation x and an internal signal s of the radiation sensor, and in which later calibrations are carried out exclusively with the internal signal. This enables the calculation of an approximate value x*(t) for the quantity of radiation x(t) absorbed in a radiation sensor (10) while taking into account a behavior of the radiation sensor that changes in time. First the primary characteristic ft1(x) is measured at a first instant t1; this characteristic describes the dependency of an output signal o on the absorbed quantity of radiation x. At the same time the secondary characteristic gt2(s) is measured, which characteristic describes the dependency of the output signal o on an internal signal s. The signals s and x should together form an intermediate signal w that is further processed with a function D(w,t) that varies in time in order to form the output signal o.

Abstract: An ultrasound imaging system for imaging ultrasound scatterers, comprising a probe (208) for transmitting ultrasound waves and detecting ultrasound echoes reflected by said ultrasound scatterers, wherein said probe comprises a first group of transducer elements, labeled transmitting group (T), to transmit ultrasound waves, and a distinct second group of transducer elements, labeled receiving group (R), to detect ultrasound echoes reflected by said ultrasound scatterers.

Abstract: The invention relates to a method for the calibration of a radiation sensor, in which method a first calibration takes place with external radiation x and an internal signal s of the radiation sensor, and in which later calibrations are carried out exclusively with the internal signal. This enables the calculation of an approximate value x*(t) for the quantity of radiation x(t) absorbed in a radiation sensor (10) while taking into account a behavior of the radiation sensor that changes in time. First the primary characteristic ft1(x) is measured at a first instant t1; this characteristic describes the dependency of an output signal o on the absorbed quantity of radiation x. At the same time the secondary characteristic gt2(s) is measured, which characteristic describes the dependency of the output signal o on an internal signal s. The signals s and x should together form an intermediate signal w that is further processed with a function D(w,t) that varies in time in order to form the output signal o.

Abstract: The invention relates to a method of forming a very accurate vascular map or road map to be associated with the current X-ray image during an invasive vascular intervention. The vascular map is derived from a four-dimensional model of the vascular tree, that is, from a spatially three-dimensional, time-dependent model, the time dependency relating to natural motions of the body such as notably the heartbeat and/or the respiration. In particular the rhythm of the heartbeat or the respiration can be determined by means of a sensor so as to be used for synchronized selection and display of the corresponding three-dimensional vascular model.

Abstract: An imaging ultrasound system is provided with an ultrasound transducer and an image processing unit for the acquisition of a three-dimensional ultrasound image of the body of a patient, and a catheter for carrying out a therapeutic or diagnostic intervention in the body of the patient. The catheter accommodates, in addition to the customary instruments necessary to carry out its task, three ultrasound receivers that are mounted at a distance from one another on the tip of the catheter and are capable of detecting the arrival of scan signals of the ultrasound transducer. The distance between the ultrasound transducer and the receivers can be calculated from the transit time of the scan signals. The receivers can thus be localized in space. Localization enables notably the selection of, for example, the plane from the three-dimensional ultrasound data that contains all three receivers of the catheter.

Abstract: The invention relates to a method of improving the precision of a medical nuclear SPECT or PET image in which notably a nuclear sectional image (n) can be superposed on a two-dimensional ultrasound image (u). For the superposition that nuclear sectional image (n0) which exhibits the best correspondence with a free-hand ultrasound image (u) is chosen from a three-dimensional nuclear image (2). In order to determine this sectional image, an evaluation index f(n,u) is calculated, on the basis of an estimated value (1), for differently situated nuclear sectional images (n). This index assigns a positive value to positions of structures (heart muscle tissue etc.) which correspond in the two images, a neutral value to structures which are represented only in the ultrasound image (u) and a negative value to structures which are represented only in the nuclear sectional image (n).

Abstract: The invention relates to an imaging ultrasound system that is provided with an ultrasound transducer (1) and an image processing unit (2) for the acquisition of a three-dimensional ultrasound image of the body of a patient (11), as well as with a catheter (9) for carrying out a therapeutic or diagnostic intervention in the body of the patient. The catheter (9) accommodates, in addition to the customary instruments necessary to carry out its task, three ultrasound receivers (10a to c) that are mounted at a distance from one another on the tip of the catheter and are capable of detecting the arrival of scan signals of the ultrasound transducer (1). The distance between the ultrasound transducer (1) and the receivers (10a to c) can be calculated from the transit time of the scan signals. The receivers (10a to c) can thus be localized in space; this enables notably the selection of, for example, the plane from the three-dimensional ultrasound data that contains all three receivers (10a to c) of the catheter.

Abstract: The invention relates to a method for reading out the image points of a two-dimensional electronic image sensor, the image being subdivided into at least two different regions (2, 3) and the region of greater interest ROI (2) being read at a scanning rate which is higher than that used for the other region (3). Consequently, the region of interest (2) can be reproduced with a higher temporal resolution while making optimum use of the limited processing capacities. Preferably, the sensitivity of the reading unit is adapted in conformity with the scanning rate of a relevant image point so as to take into account the fact that image points that are read out less frequently collect a light intensity over a prolonged period of time and hence may reach high signal strengths. Regions that are less frequently read out can also be irradiated with a lower radiation intensity by applying appropriate masking. The method is very suitable for the imaging of time-critical processes in medical X-ray applications.

Abstract: An ultrasound imaging system for imaging ultrasound scatterers, comprising a probe (208) for transmitting ultrasound waves and detecting ultrasound echoes reflected by said ultrasound scatterers, wherein said probe comprises a first group of transducer elements, labeled transmitting group (T), to transmit ultrasound waves, and a distinct second group of transducer elements, labeled receiving group (R), to detect ultrasound echoes reflected by said ultrasound scatterers.

Abstract: The invention relates to an X-ray examination apparatus and a method for forming an X-ray image by means of a processing unit (2) for the correction of image data. In order to achieve automatic correction of imaging defects that are caused by imperfections in the imaging and processing chain, the processing unit (2) is succeeded by a defect detection unit (3) for the detection of image defects that can be detected on the basis of image parameters that can be extracted from image data acquired during clinical examinations, and is suitable for adapting processing parameters (15-21) that are used in the processing unit (2) in dependence on the detected image defects.

Abstract: The invention relates to a method of and a device for forming an image which is composed of a plurality of sub-areas, a read-out unit being associated with each sub-area and image data of adjoining image areas of neighboring sub-areas being evaluated in order to mitigate differences in amplification, which device includes a detector with a plurality of sensor elements for forming image data, read-out units which are associated with the sub-areas of the image, an analysis unit which is arranged to evaluate image data from adjoining image areas of neighboring sub-areas and to generate correction data, a correction unit which is arranged to correct incorrect image data by means of correction data, thus enabling a regular and accurate recalibration or correction of non-linear amplifier behavior to be performed without necessitating an additional X-ray dose or interventions by the user.