U.S. Philips Corporation

Hermann Weiss

Erhard P Klotz

Rolf E Linde

Ulf Tiemens

Wilfried Mauser

Gunter Kowalski

Klaus Pasedach

Wolfgang Wagner

Dietrich Meyer-Ebrecht

Horst Peemoller

William J Dallas

Gunther Groh

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.

Fluoroscopy apparatus for forming layer images of a three-dimensional

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.

Method of and device for forming an image of a layer of a

In fan beam X-ray scanners operating with a large number of detectors, errors at and near the center of rotation are caused by the fact that the radiation absorption in said area is substantially always measured by the same detectors and that the sensitivity of all detectors is not exactly the same. The invention provides an improvement in that the measurement is carried out with a larger number of detectors than is necessary for the measurement of the scanning field and that the detectors pivot during the measurement. As a result, the absorption in the center of rotation is measured by different detectors so that, for a sufficient number of detectors the different sensitivities, errors are averaged and thus reduced or cancelled.

Fan beam CT scanner with compensating detector motion

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.

Device for producing images of a layer of an object from multiple shadow

Method of and device for coding and decoding an image of an object by

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.

Device for reconstructing layer images of a three-dimensional object by

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.

Device for forming layer images of a three-dimensional object by means

Disclosed is a method of making an inverse filter wherein a single photographic plate is illuminated by the object and reference waves so as to expose the photographic material in the logarithmic portion of its transmittance versus illumination curve to thereby form a holographic image which upon development forms the inverse filter.

Method of manufacturing inverse filters by holographic techniques

A method of coding and decoding of objects by means of a large number of point-like radiation sources which are subdivided into two groups. Two recordings are made of an image object. A first recorded image is made on a first recording medium with a first radiation source distribution. A second recorded image is made with a second radiation source distribution which is determined by the autocorrelation function of the first distribution. In the second radiation source distribution, the source which is determined by a function value in the origin of the autocorrelation function is omitted. In a first decoding step, the first recorded image is decoded with a point image function of the first radiation source distribution. In the second decoding step, the second recording is subtracted from the decoded first recorded image, so that an artifact-free image of the object is produced.

Coding and decoding artifact-free images of objects

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.

X-ray apparatus for tomosynthesis

In third generation computer tomography apparatus, wherein radiation behind the object is measured by means of a large number of detection elements, a detection device comprises a number of detection elements which is larger than necessary for the measurement of the fan-shaped radiation beam, per se, in a direction parallel to the axis of rotation. Means are included for displacing the detection device in the direction of the axis of rotation. Detector element unbalance effects are thus averaged.

Device for measuring the absorption of radiation in a slice of a body

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.

Image coding and decoding using coherent codes

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.

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Hamburg, Germany

Hermann Weiss