Abstract: A method reconstructs a reconstruction data set containing virtual X-ray images of projection images of a target region recorded with an X-ray device. The projection images being recorded at different positions of an X-ray source along a scanning trajectory. The method includes defining an imaginary position of the X-ray source for each virtual X-ray image. For each virtual X-ray image and each pixel to be reconstructed in the X-ray image a virtual beam section, covering the target region, of the path between the imaginary position of the X-ray source and the pixel is defined. For each projection image, an integral is determined from the relationships between the forward projection and the filtered back-projection by re-parameterizing. A projection value of the virtual X-ray image from the integrals determined is combined.

Abstract: Artifacts result from unrecorded, stochastically distributed relative movements of a radiation source, radiation detector, and/or the object during a scanning process. The artifacts occur when a three-dimensional image dataset is reconstructed from two-dimensional projection images acquired from different projection directions. Geometric parameters describing an acquisition geometry for each projection image are taken into account during the reconstruction. The correction includes filtering the projection images to obtain a set of filtered first intermediate images. A set of second intermediate images are formed by filtering the projection images with a second filter. A three-dimensional reconstruction dataset is constructed from the filtered projection images filtered by way of the second filter, and forward projection is applied in the projection directions.

Abstract: A method and a device for displaying an object with the aid of X-rays include recording a multiplicity of X-ray projections from which a volume data set characterizing the density of the object is reconstructed. Subsequently, density values along a ray are determined on the basis of the volume data set. By carrying out low pass filtering for the density values along the ray, and determining the maximum of the filtered density values (maxima of the filtered density values), values are obtained for displaying the object which simultaneously effectively image fine structures and are scarcely subject to the influence of artifacts.

Abstract: A method for obtaining a 3D image dataset of an object of interest is proposed. A plurality of 2D X-ray images are captured and a 3D reconstruction is carried out using filtered back projection. The projection parameters have been measured with the aid of a calibrating phantom, possibly using an interpolation or extrapolation of such measurements. A model of effect strings of the components in an X-ray imaging device is obtained, and the model parameters are identified based on imaging of a calibrating phantom. A projection matrix can then be calculated for any positions on any desired trajectories, without having to use imaging of a calibrating phantom at precisely that position and desired trajectory.

Abstract: An alternative analytical method for tomographic reconstruction in the 2D parallel-beam geometry is presented. This method may follow a filtering and backprojection scheme and may involve a global filtering in the projection domain and a local filtering in the image domain. For example, the method may include applying Hilbert filtering to the received projection data, computing an antiderivative of the filtered data, backprojecting the antiderivative into the image domain, and computing the 2D Laplacian of the backprojection image.

Abstract: A method for reconstruction of a two-dimensional sectional image corresponding to a sectional plane through a recorded object from two-dimensional projection images recorded along a recording trajectory at different projection angles with an X-ray device is proposed. The sectional plane having at least two intersection points with the imaging trajectory is selected. After selection of the sectional plane, an intermediate function on the sectional plane is determined by backprojection of the projection images processed with a differentiation filter. The object densities forming the sectional image are determined from the intermediate function by a two-dimensional iterative deconvolution method.

Abstract: A method for reconstruction of an actual three-dimensional image dataset of an object during a monitoring process is proposed. Two-dimensional X-ray projection images which correspond to a recording geometry are continuously recorded from different projection angles. The three-dimensional image dataset are reconstructed from a first number of these projection images, especially by a back projection method. The proportion of the oldest projection image contained in the current three-dimensional image dataset is removed from the three-dimensional image dataset and the proportion of the actual projection image is inserted in the three-dimensional image dataset after each recording of the actual projection image.

Abstract: At least one embodiment of the invention relates to a method for the reconstruction of image data from an examined object, using measuring data, wherein the measuring data were first recorded during a relative movement between a radiation source on a computer tomography system and the examined object. In at least one embodiment, the image reconstruction is based on a back projection of the filtered measuring data. During the back projection, a back projection weight that depends on the respective image point is used and the power with which the back projection weight is used is selectable.

Abstract: A method for acquiring a 3D image dataset is proposed. A 3D X-ray image dataset of an image object is acquired during scanning of a partial circle by X-ray radiation source and X-ray radiation detector. A first and a second 3D image datasets are calculated from the acquired image dataset. Redundancies are eliminated by averaging the first and second 3D image datasets. A filtering that is antisymmetric in respect of a center of symmetry is performed in respect of the 2D image datasets in calculating the second 3D image dataset. Said filtering has a row-by-row Hilbert transform. Suitable weights can be specified based on an axis defined in space.

Abstract: A method for recording and reconstructing a three-dimensional image dataset is proposed. A plurality of projection images are acquired under different recording geometries in relation to an object to be recorded by an X-ray apparatus, in particular a C-arm X-ray apparatus. At least two projection images are recorded for at least one recording geometry, in particular for every recording geometry. The three-dimensional image dataset is reconstructed from the project images.

Abstract: A configuration and an associated operating method for tomosynthetic fluoroscopy utilize an x-ray emitter and with an x-ray detector. The configuration further contains a mounting device, which is rotatably mounted about a rotational axis and about which the x-ray emitter is arranged such that the optical axis of the x-ray emitter is directed to the x-ray detector and that, in the case of a rotation of the mounting device, the focus of the x-ray emitter describes a circular path. An advantage offered by the invention lies in ensuring robust tomosynthetic fluoroscopy.

Abstract: In a method and x-ray device to determine a three-dimensional target image data set showing at least one partial region of interest of an acquisition region, wherein the image data of the three-dimensional target image data set are reconstructed from two-dimensional projection images acquired from various projection directions, first projection images are acquired without a collimation of the radiation source from first projection directions and a three-dimensional overview image data set of the acquisition region is reconstructed from the first projection images. The partial region of interest is selected in the overview image data set. Second projection images are acquired, with collimation at the partial region, from second projection directions, the second projection directions differing from the first projection directions. The target image data set showing the acquisition region and the partial region of interest is reconstructed from all first and second projection images.

Abstract: A method for determining at least one three-dimensional image data record to be displayed of a target area from two sets of projection images recorded with x-ray spectra using different energy maxima. The method includes recording the first projection image via a first X-ray spectrum and different first projection directions and of the second projection image via the second X-ray spectrum and different second projection directions. The second projection directions differ at least partially from the first projection directions. A three-dimensional anatomy image data record is reconstructed from the first and the second projection images. A three-dimensional spectral image data record is reconstructed by a weighted combination of a first three-dimensional reconstruction image data record, reconstructed from the first projection images, and a second three-dimensional reconstruction image data record is reconstructed from the second projection images.

Abstract: For filtered back-projection of a projection image data set, the projection image data set is cosine-weighted. The cosine-weighted projection image data set within the image plane of the projection image data set is subjected to a two-dimensional Radon transformation. The Radon transform of the cosine-weighted projection image data set differentiated with respect to the distance from an image origin of an image coordinate system. The derivative of the Radon transform is redundancy-weighted. The redundancy-weighted derivative is subjected to a two-dimensional Radon back-transformation. The Radon back-transform is differentiated and back-projected with respect to an image column coordinate. A differentiation step width entering into the differentiation is varied depending on depth.

Abstract: A method and a device for determining attenuation coefficients for an object using a movable X-ray source and a detector, which is provided for recording projections, is provided. The method includes specifying a trajectory for the movable X-ray source, specifying positions on the trajectory for determining a derivative of projections recorded by the detector, specifying a plurality of scanning positions for each of the specified positions, following the trajectory with the X-ray source and recording a projection for each scanning position, numerically calculating a projection derivative in relation to the trajectory path for each of the positions using the projections recorded for the associated plurality of scanning positions, and determining attenuation coefficients for the object from the calculated projection derivatives using a theoretically exact or approximate rule for the reconstruction.

Abstract: A method for correcting artifacts in an image dataset reconstructed by filtered back projection is proposed. The artifacts are occurred as a result of temporal changes of attenuation values during rotational recording of X-ray projection images with an angular speed. A linear, analytically-derived, filter-type relationship between the attenuation values of the image dataset at a reference point and the real attenuation values is determined from the sum of a respective application of an angle speed-dependent weighting factor, a point spread function and a temporal derivation, evaluated at the reference time. The linear relationship is inverted and the inverted linear relationship is applied to the attenuation values of the image dataset for the correction.

Abstract: A method for recording a projection dataset of a object to be recorded using a plurality of X-ray sources is provided, which X-ray sources are spaced apart from one another on average by an angle ? relative to an isocenter. A plurality of projection images from different recording directions are recorded in succession while activating the corresponding X-ray sources. Two X-ray sources are activated in succession having a spacing of at least 2 ? relative to the isocenter.

Abstract: Artifacts result from unrecorded, stochastically distributed relative movements of a radiation source, radiation detector, and/or the object during a scanning process. The artifacts occur when a three-dimensional image dataset is reconstructed from two-dimensional projection images acquired from different projection directions. Geometric parameters describing an acquisition geometry for each projection image are taken into account during the reconstruction. The correction includes filtering the projection images to obtain a set of filtered first intermediate images. A set of second intermediate images are formed by filtering the projection images with a second filter. A three-dimensional reconstruction dataset is constructed from the filtered projection images filtered by way of the second filter, and forward projection is applied in the projection directions.

Abstract: A method for reconstruction of a three-dimensional image data set from projection images of an object captured with an X-ray device from different projection angles is proposed. At least one sub-area of the object is outside the coverage of the X-ray device, or as a result of strong attenuation by a metal so that no projection data is present in the sub-area. Filter lines are determined n the projection images. A first local transformation is performed along the filter lines on the projection images. The missing projection data on the transformed projection data is augmented. A non-local transformation is performed on the transformed projection data for determining of filtered, augmented projection data. The non-local transformation is different from a ramp filter which is created by the first local transformation and the non-local transformation. The three-dimensional image data set is determined by back-projection of the filtered, augmented projection data.

Abstract: An X-ray imaging apparatus has at least one X-ray image system rotatable about an examination volume. The X-ray image system is controlled such that during a continuous rotation of the system, at least one 2D projection image is recorded. An image generation facility generates the 2D projection image from the measured data. The X-ray source includes an X-ray focus which can be changed in terms of position, which, during the recording of the 2D projection image, moves counter to the direction of rotation of the X-ray image system such that its spatial position in a fixed coordinate system does not change. The X-ray detector records several 2D partial images, from which the 2D projection image is calculated with the rotational movement of the X-ray detector being at least approximately compensated. The 2D projection images have significantly reduced image blur.