Abstract: A radiation detector device for detecting a primary radiation includes a scintillator which generates a converted primary radiation in response to incoming primary radiation and a photo detector for detecting the converted primary radiation. The radiation detector device further includes a secondary radiation source for irradiating the scintillator with a secondary radiation which has a wavelength different from a wavelength of the first radiation and which is capable of producing a spatially more uniform response of the scintillator to primary radiation.

Abstract: According to an embodiment of the invention, a radiation detector device (10) for detecting a primary radiation (6) comprises a scintillator (12) which generates a converted primary radiation in response to incoming primary radiation (6) and a photo detector (14) for detecting the converted primary radiation. The radiation detector device (10) further comprises a secondary radiation source (20) for irradiating the scintillator (12) with a secondary radiation (22) which has a wavelength different from a wavelength of the first radiation (6) and which is capable of producing a spatially more uniform response of the scintillator (12) to primary radiation. In an embodiment of the invention, the radiation detector device (10) is an X-ray detector of an X-ray imaging apparatus where the primary radiation is X-ray radiation and the secondary radiation has a wavelength between 350 nm and 450 nm. According to an embodiment, the irradiation with the secondary radiation, e.g.

Abstract: An X-ray examination apparatus includes an X-ray source (1) for emitting an X-ray beam, an X-ray detector (6) for detecting an X-ray image and converting it into an optical image, and a video extractor (8) which is coupled to the X-ray detector (6) via optical coupling means (9). The optical coupling means (9) is provided with an optical pick up (11) for feeding a fraction of the light flux to a photosensor (12) which produces a control signal for adjusting the X-ray flux from the X-ray source (1). The photosensor (6) is provided with an array of pixels, with weighting means for the signals detected in or by each of said pixels, and with means for determining a mean value of the detected and weighted signals, yielding a control signal which is fed back in order to adjust the X-ray flux from the X-ray source (1).

Abstract: An X-ray examination apparatus comprises an X-ray detector (1) for deriving an optical image from an X-ray image. An image pick-up device (2) derives an image signal from the optical image. The image pick-up device (2) is provided with an image sensor (3,4) having a plurality of sensor elements. The effective surface area of the sensor elements differs for different optical spectral components of the optical image. The image pick-up device is provided with an adjusting system for selecting an optical spectral component. The image signal is derived from the selected optical spectral component.

Abstract: An imaging arrangement including a multi-sensor for use in an x-ray examination apparatus is described that combines a plurality of partially overlapping sub-images, resulting in an increased effective sensor area when compared to a single sensor-image. Thus an imaging arrangement is provided suitable for imaging a large area output screen of an image intensifier by way of semiconductor image sensors. Image artifacts owing to variations in the alignment of the respective image sensors are corrected for by applying geometric transformation to respective electronic sub-image generated by the image sensors. The transformed electronic sub-images are assembled into a recombined image. Further image quality improvement is obtained by performing evening operations in overlapping regions of the transformed sub-images.

Abstract: An image pick-up apparatus (1) which includes a beam splitter (2) for splitting an image into sub-images and several image sensors (3, 4) for picking up the sub-images is provided with a depolarizing element (6) for reducing the linear polarization degree of the light incident on the beam splitter. The electronic image signals of the image sensors (3, 4) are combined so as to form an electronic image signal of a composite image in a combination unit (5). Because the linear polarization degree of the light incident on a mirror surface (27) of the beam splitter (2) is low, the differences between brightnesses of sub-images picked up by individual image sensors are small. Disturbances are thus counteracted in the composite image.The image pick-up apparatus is preferably used in an X-ray examination apparatus (10) in order to reproduce an X-ray image having a high spatial resolution and few disturbances.

Abstract: An X-ray examination apparatus (1) includes an X-ray source (2) and an X-ray image intensifier (5) for deriving an optical image from an X-ray image, which optical image is picked up by means of an image pick-up apparatus (6). The X-ray examination apparatus also includes an exposure-control system (7) for adjusting the X-ray source and/or the image pick-up apparatus on the basis of brightness values of a region of interest in the optical image. The exposure-control system includes a photodetector, for example a CCD sensor, for deriving a photodetector signal from the optical image and a photosensor for adjusting the sensitivity of the photodetector. The photodetector (9) includes an image pick-up section (11), an image memory (13) comprising separate sections, preferably including an intermediate memory (15). An electronic image in the image pick-up section is quickly transferred to an available storage section after which it is read out as an electronic image signal.

Abstract: An imaging device is provided with an image sensor element (1) for electromagnetic radiation (11) with a covering body (2) which is transparent and to the radiation (11) through which the radiation (11) can reach the sensor element (1). The imaging device is characterized in that a transparent electrically-conducting layer (3) is provided on the covering body (2) and is provided with two connection electrodes (4, 5) for heating of the covering body (2) with an electric power supplied through the electrodes (4, 5) and dissipated in the transparent layer (3). It is possible with such an imaging device to prevent condensation of a water film on the covering body (2) under conditions where the temperature of the covering body (2) lies below the dew point of the surroundings.

Abstract: X-ray imaging system is arranged such that the exit screen of the X-ray image intensifier can be imaged, via a beam deflection element, on a pick-up device (CCD sensor) and on a photodiode for automatic dose control or exposure timing. Because the beam deflection element (prism, partly transparent cube or mirror) covers the entire cross-section of the exit screen, a uniformly illuminated exit screen is imaged on the pick-up device as a uniformly illuminated surface. When the pick-up device is arranged transversely of the prolongation of the X-ray image intensifier and the photodiode is arranged in the prolongation of the X-ray image intensifier, a compact system is obtained. When use is made of an anamorphic system comprising two prisms, a part of the light beam can be reflected to the photodiode from a surface of a prism. More accurate exposure timing can be achieved by measurement of the light reflected by the CCD sensors.

Abstract: Accurately aligning opto-electronic image sensors with respect to a beam-splitter being comprised in an image sensing device is facilitated by incorporating an alignment pattern in the conductive metal stripes of the opto-electronic image sensors. When simultaneously viewed through the input face of the beam-splitter, alignment patterns of respective opto-electronic image sensors form a combined alignment patterns showing the accuracy of the alignment of the opto-electronic image sensors. By providing differences between pitches of the alignment patterns on either side of an axis of reflection, a combined alignment pattern is obtained showing various types of alignment errors, such as horizontal or vertical translation, or rotations. Quantification of alignment errors is facilitated by making use of vernier action in the combined alignment pattern.

Abstract: An X-ray examination apparatus includes an X-ray source (10) and an image intensifier (30) with an imaging screen (32). The imaging screen (32) is imaged on the pick-up face (51) of an image pick-up device (50), for example a television camera. In order to adjust or maintain the optimum response time of the image pick-up device (50) to or at the desired level, the pick-up face (51) is illuminated by means of a number of illumination elements (145). In order to achieve a compact construction of the apparatus, the illumination elements (145) are accommodated in recesses (144) in a transparent element (141). The light of the illumination elements (145) is then reflected from the entrance face (142) facing the image intensifier (30) and/or from the sides (147) of the element (141). The transparent element (141) may be a prism so that the optical path between the image intensifier (30) and the image pick-up device (50) is folded.

Abstract: An x-ray examination apparatus includes an imaging arrangement, devised for performing fluoroscopy. Which has image sensors that are efficiently optically coupled with an x-ray sensitive radiation conversion screen. Consequently, the image sensors produce an electrical signal having a high signal-to-noise ration when low doses of x-radiation are administered. An x-ray conversion screen is provided with a tapetum filter so as to concentrate light in the forward direction. Furthermore, the x-ray conversion screen is preferably fitted with a light reflecting layer for reflecting light that has been reflected by the tapetum filter, said light reflecting layer being transparent for x-radiation. Further concentration of light in the forward direction is achieved by placing a light-transparent material having a suitable refractive index between the radiation conversion screen and lenses that concentrate the light onto the image sensors.

Abstract: X-ray images are generated from a CCD image sensor having an image section and at least one storage section by performing a first X-ray exposure during a first time interval (T.sub.1) which is shorter than the read-out period (T.sub.r) of an image stored in the storage section of the CCD image sensor (7) to form a first image in the image section, transferring the first image from the image section to the storage section after expiration of the first time interval (T.sub.1), performing a second X-ray exposure directly after or a small interval in time after the first X-ray exposure during a second time interval (T.sub.2) which is short in comparison with the read-out period (T.sub.

Abstract: A solid-state imaging apparatus comprising a solid-state image sensor which is rotatable around an axis is provided. Adjusting the optical axis at right angles to the solid-state image sensor, aligning the optical axis with the rotational axis and centring the optical axis at the centre of the solid-state image sensor are performed employing adjustment members having a convex spherical contact face and a concave spherical support face. Employing such adjustment means is particularly advantageous when used in conjunction with a solid-state image sensor because such adjustment members are particularly effective in making a light-light construction and in discharging heat from the solid-state image sensor.

Abstract: An imaging system includes an image pick-up device with an image sensor having a rectangular detection face which is subdivided into discrete detection sub-faces for converting a radiation intensity distribution on the detection face into an electric signal, the detection sub-faces being arranged in a matrix of n rows and p columns respectively dividing short and long sides of the detection face, an object plane and an optical system which images a radiation intensity distribution in a circle situated in the object plane onto an ellipse situated on the detection face in accordance with a compression factor m. The compression factor may be chosen so that the ellipse spans no more than p/2 columns of the detection face so that video images can be formed at twice the conventional rate. In the case of non-square detection sub-faces, the compression rate may be chosen so that the ellipse spans an equal number of rows and columns, thereby making each detection sub-face correspond to a square in the object plane.

Abstract: The X-ray examination apparatus (1) comprises an X-ray image intensifier tube (19) having an entrance screen (21), an exit section (24) having an exit screen (25) and an exit window (27), an optical imaging system (32) and a photosensitive detection device (41). The exit section (24) comprises a fibre optical plate. Between the fibre optical plate and the optical imaging system (32) there is quartz birefringent crystal element (31) which selectively increases the optical spatial frequency of the image processed thereby in order to correct for image aberrations introduced by the fibre optical plate structure.

Abstract: Between an image intensifier (II) having a circular radiation exit surface (II2) and an image sensor in the form of a solid state sensor (CTD) with a rectangular picture pick-up surface (PP) there is arranged an optical coupling system (OP) for producing an ellipsoidal picture (EL) of the circular radiation exit surface (II2) within or at least partly around the rectangular picture pick-up surface (PP). A signal correction device (GEN, CTD or PROC, respectively) is provided for compensating the adaptation of the optical coupling system, whilst the sensor may form part of said device (GEN, CTD), said compensation being effected by adapting the clock pulse frequency so that the corrected picture signal produces the image in a circular surface (DIS) on a screen (MIS) of a picture display device (MON).