Abstract: A method is disclosed for generating images of a human or animal body on the basis of 3D-reconstructions from 3D-XRAY or 3D-Computer Tomography measurements, which bodies comprise both natural tissue and one or more high-density objects. The method comprises the steps of executing the measurements, distinguishing the one or more high-density objects and executing a separating procedure thereon for generating an improved image of regions of the natural tissue. In particular, the method comprises the following steps: applying a ramp filter on the various projection measurements to single out the one or more high-density objects; segmenting the singled-out one or more high-density objects into a separate 3D reconstruction; suppressing the reconstructed one or more high-density objects from the original projection measurements; and segmenting said projection measurements without the suppressed one or more high-density objects.

Abstract: A method of generating layer images from a number of single-shadow images and a device for performing this method. The absorption values associated with the image points of the single-shadow images are stored in a memory. The image value of the layer-image point is formed from the lowest absorption values associated with this layer-image point. Structures or artefacts which are situated outside the layer being imaged can thus be eliminated from the image.

Abstract: A tomosynthesis apparatus for the formation of layer images of a body. The apparatus has a large number of radiation source positions which are situated in one radiation source plane. The radiation from the sources in stopped by a diaphragm device so that the radiation beams passing through the diaphragm apertures irradiate a common superposition zone and are incident on a detector surface which is arranged behind the superposition zone. The diaphragm apertures are shaped so that in the detector plane the edge of the radiation beam of each radiation source is at least locally tangent to the edge of a cylinder which is centrally projected onto the detector surface by the radiation source and which is situated within the superposition zone. The axis of the cylinder extends at least approximately perpendicular to the radiation source plane.

Abstract: In a short-time tomosynthesis apparatus for imaging layers of a body to be examined, the body is irradiated by radiation beams from a large number of different directions in order to form perspective images. The radiation beams are detected by a detector which is arranged underneath the body. The perspective images appearing on the exit of the detector will overlap when the radiation beams have a comparatively large angle of aperture. For separating the perspective images, an image separating system is provided at the exit of the detector. The image separating system may comprise a fiber-optical system or an electron-optical deflection unit.

Abstract: A device for reducing artefacts in layer images. Several layer images are formed of an object layer by irradiation from different directions. The same points of these layer images are compared in order to obtain a corrected layer image: when corresponding image information is present in all image points compared, the image information is transferred to corresponding layer image points in a corrected layer image; when the image information in the compared image points is not the same, that information is at least partly suppressed.

Abstract: Apparatus for the layer-wise imaging of an object by means of a large number of radiation sources which are situated in a radiation source plane and whose radiation beams intersect one another so that the approximately equally large radiation beam cross-sections which are situated in one irradiation plane almost completely cover one another. A record carrier is arranged on the other side of the object in order to record perspective images produced by the radiation beams. A imaging matrix which comprises imaging elements for the superposition of the perspective images on an image display device is disposed behind the record carrier. Displacement means are provided in order to realize a relative movement between the irradiation plane and the object or an object table carrying the object.

Abstract: The invention relates to a method of and a device for forming images of a layer of a three-dimensional object. In order to obtain high-quality images, the object is irradiated by means of a necessarily large number of radiation sources which are arranged in different mutually parallel planes or which are arranged to be displaceable (for example, rotatable) with respect to the object. Alternatively, the object with the record carrier (X-ray film) may be arranged to be displaceable with respect to the radiation sources. In the decoding step (superposition and summing of the shadow images) use is made of the two dimensional distribution of all radiation sources used during coding (irradiation) of the object.

Abstract: The invention relates to a device for producing images of a layer of a three-dimensional object, with radiation sources arranged in a radiation source plane, for irradiating the object with beams of rays from different directions, and with several planar recording layers, arranged parallel to one another, of recording all said shadow images, wherein before each recording layer there is arranged a diaphragm arrangement that has been allocated to it for (stepwise) masking of the beams of rays, and wherein the diaphragm apertures of each diaphragm arrangement are so much the smaller, the greater the distance the diaphragm arrangement is from the radiation sources.

Abstract: The invention relates to a device for the imaging layers of a three-dimensional object. The device comprises a group of radiation sources which are situated in a common radiation source plane in order to irradiate an object arranged on an examination table. The drive also comprises a record carrier situated underneath the object for recording a source-distribution encoded image of the object. The encoded image consists of respective perspective images. The radiation source group and the record carrier are arranged to slide in opposite directions in parallel planes relative to the stationary object during a radiographic recording. Each of the connecting lines between the radiation sources and the center of the record carrier, pass through a corresponding fixed point in the object for all positions of the radiation source group.

Abstract: A device for imaging layers of the interior of a three-dimensional object. The object is irradiated from a large number of radiation source positions which are distributed in one plane from this, a coded image of the object which coded image consists of separate perspective images is produced. The coded image is illuminated and imaged by means of an imaging matrix whose imaging elements are distributed in the matrix plane according to the flat distribution of the radiation source positions. Layer images of the object are formed on a photosensitive element by the superposition of the perspective images. For forming different layer images of the object, the imaging elements are positioned in different distributions of changed scale with respect to the distribution of the radiation source positions.

Abstract: For the formation of layer images of a three-dimensional object, the object is irradiated from a large number of radiation source positions which are situated in one plane. Thus, a coded image of the object, consisting of individual perspective images, is formed. Subsequently, the coded image is illuminated and the perspective images thereof are superposed for the reconstruction of the object by means of a lens matrix which extends parallel to the plane of the coded image and whose flat lens distribution corresponds to the distribution of the radiation source positions. In the superposition zone of the perspective images, a photosensitive element is introduced in order to form individual layer images of the object. For the formation of the different layer images on the photosensitive element, the lens matrix is displaced in the direction of the optical axis, and the photosensitive element is positioned each time within the depth of focus range of the lenses of the lens matrix.

Abstract: Apparatus for examining objects includes a group of X-ray sources, which are activated group-wise by a generator. A group of sub-images are separately projected onto a photographic film. During a subsequent step, the film is re-imaged with the aid of an optical lens matrix the lenses in the matrix are arranged in a manner similar to the X-ray sources.

Abstract: The invention relates to a method of eliminating errors in images of patterns which consist of periodically arranged individual images by optical filtering, only certain selected diffraction orders of the regular pattern to be imaged in the form of a ring or parts of a ring being employed for further imaging.

Abstract: A method for forming a layered image of a three-dimensional object which is irradiated from different directions by a plurality of radiation sources. n coded superposition images, in different image planes, of a single movement phase are sequentially recorded on a mechanically moved detector face. Decoding of the n superposition images is realized by means of a coordinate matrix whose coordinates correspond to the geometry of the radiation source distribution, so that these images are successively electronically superposed and summed, for a number of times which equals the number of radiation sources. The same layer of the object is decoded n times and the n decoded layers are summed to form a layered image.

Abstract: A method of imaging a three-dimensional object with the aid of coding and decoding using coherent point codes, whereby the object is recorded in two steps, each with a plurality of radiation sources of different orientation on the same recording material.Negatives of the two images are produced, after which the positive of one image is combined with the negative of the other image, the combined images being subsequently multiplied by means of point holograms formed with the aid of a reference wave and a multiplicity of light sources whose co-ordinates correspond to those of the point images of the two source arrays recorded by a pinhole camera, the two multiplied images being superposed in one plane, the coded images being decoded by changing their scale with the aid of two synchronously controlled zoom lenses whereby the coordinates of the point image function of an image of an object layer in the coded images are adapted to the points stored in the two point holograms.

Abstract: A method of decoding composite images of three-dimensional objects which are coded by means of a large number of radiation souces of different perspective and which are decoded by means of a point hologram. The point hologram is produced by means of a flat reference beam and by illuminating a shadow mask in the converging beam. The coordinates of the shadow mask correspond to the point image of the source distribution recorded by a hole camera, while the coordinate differences of the holes of the shadow mask have the same value, or a value increased to scale, with respect to the coordinate differences of the point image function of the object plane of the composite image which was nearest to the source distribution during the recording. The decoding of the composite image is effected by shifting between an illumination lens and the point hologram in an incoherent monochromatic converging beam.