Abstract: X-ray examination apparatus including a filter An X-ray examination apparatus (1) includes an X-ray source (2), an X-ray detector (5) and an X-ray filter (6). The X-ray filter (6) is arranged between the X-ray source and the X-ray detector. The X-ray filter (6) includes a plurality of filter elements (7) whose X-ray absorptivity can be adjusted by adjusting a quantity of X-ray absorbing liquid (30) present in individual filter elements (7). The filter elements are formed by substantially parallel plates (8), respective plates being provided with separating members (10) which project approximately transversely from the plane of such a plate. The filter elements are formed notably by parallel corrugated plates or by parallel plates provided with partitions extending transversely from the plates.

Abstract: The invention relates to MR guided intervention. For biopsies and similar interventions the challenge is to align a needle or other interventional device along an anticipated trajectory which hits a target point but does not intersect sensitive structures between the target and the surface. The invention includes the following method in order to position an MR visible device: collection of pre-intervention MR-images, establishing of an anticipated trajectory and an entry point by imaging of the MR-visible device and a thick slab positioned parallel to the surface and displaying of the MR localizer in the MR-image of the slab and moving the MR visible localizer to the entry point, imaging of two mutual orthogonal slices passing through the anticipated trajectory between the entry point and the target point and establishing an angle of entry by using for example a MR-visible pen and a targeting device.

Abstract: An X-ray generator for powering an X-ray tube, has at least two electron sources for forming focal spots of different sizes at the same area of the anode. The resolution can be adapted to relevant requirements by associating each electron source with a respective control unit which produces an electron flow between the associated electron source and the anode, which flow is dependent on a control signal at a control input of the control unit, the two control units being activatable during an X-ray exposure and each control signal being adjustable, and hence also the ratio of the mAs products supplied by the electron sources.

Abstract: A method for determining the thickness of a thin sample is described. The method includes the step of exciting time-dependent acoustic waveguide modes in the sample with an excitation radiation field. The acoustic waveguide modes are detected by diffracting probe radiation off a ripple morphology induced on the sample's surface by the acoustic waveguide modes. The diffracted probe radiation is then analyzed to measure phase velocities or frequencies of the acoustic waveguide modes. A thickness of the thin sample is determined by comparing the measured phase velocities or frequencies to the phase velocities or frequencies calculated from a mathematical model.

Abstract: An image is processed taking into account the direction of a predominant structure of the image. Said predominant direction is derived from image information in the image. In particular, the covariance matrix having matrix elements depending on products of differences between pixel-values in separate directions is calculated. The eigenvectors of the covariance matrix correspond with the predominant direction of the image structure and the eigenvalues of the covariance matrix represent the strength of the structure in the image. The covariance matrix is computed locally, i.e. for separate regions in the images so as to take variations of the direction of predominant structures into account.

Abstract: An X-ray examination apparatus includes an X-ray detector (1) for deriving an image signal from an X-ray image and an exposure control system (2) for adjustment of the X-ray examination apparatus. The exposure control system includes an arithmetic unit (4) for forming a histogram of brightness values of the X-ray image and for deriving therefrom an image component which relates mainly to brightness values representing relevant image information. The exposure control system is arranged to adjust the X-ray examination apparatus on the basis of the image component.

Abstract: A method for secure anonymous querying by a user of an information provider by electronic mail and for obtaining a reply uses a public key of the provider to form an electronic encrypted query package containing information including a query, a generated random number sequence, a hash of the query, a generated public key of the user, and an identification of a public bulletin board. The query package is preferably sent to the provider via a network from a public terminal. At the information provider the query package is received and decrypted. If the result of hashing the decrypted query is equal to the decrypted hash, a response R is formulated. A response package is formed therefrom by using a generated symmetric key of the information provider and the public key of the user. The response package is posted to the public bulletin board along with the random number sequence.

Abstract: A fingerprint sensing device comprises an array of sense elements (12) each of which includes a sense electrode (14) which together with an overlying fingerprint portion forms a capacitor (35). The capacitor is charged by operation of a first switching device (16) via a first address conductor (18). A second switching device (17) is then operated to transfer the charge on the sense electrode to a second address conductor (20) where it is sensed (24) and an output indicative of capacitance provided accordingly. Fast, reliable, scanning is achieved. A row and column array of sense elements is conveniently addressed using sets of row and column conductors (18, 20) and the device can readily be implemented using thin film devices, e.g. TFTs, as the switching devices on an insulating support and with integrated drive circuits.