Abstract: In an apparatus for recording image information in an image recording medium including a photoconductor, a preliminary electric field is applied to the photoconductor before application of a recording electric field, which is applied to the photoconductor for recording the image information, and the preliminary electric field is stronger than the recording electric field. In addition, in an apparatus for reading image information carried by an electromagnetic wave by using a photoconductor, a preliminary electric field is applied to the photoconductor before application of a reading electric field, which is applied to the photoconductor for reading the image information, and the preliminary electric field is stronger than the reading electric field.

Abstract: An X-ray image converter (2) for recording and evaluating information gained from X-ray investigations of persons (3), animals or objects and other purposes is suggested, which comprises a carrier (4) of a material in which the impinging X-ray radiation causes detectable changes, as well as a method for recording X-ray images, wherein changes in charge carriers on the surface of a carrier (4) are determined for evaluation of the radiation from the object (3) being observed.

Abstract: A self-modulated solid state laser comprises an intracavity optical waveguide that supports a multiplicity of lasing filaments each at a different optical frequency. At least two of the filaments temporally beat with one another so as to modulate the intensity of the laser output. In accordance with one embodiment of our invention, the waveguide supports a multiplicity of transverse modes, and the laser includes a mode mixing mechanism that mixes the energy of at least two pairs of the modes, each coupled pair generating a separate filament. In an illustrative embodiment, the filaments are mode locked and the laser output is modulated at a frequency on the order of 1 THz.

Abstract: The so-called memory effect occurring in a device for forming X-ray images by means of an X-ray image converter which includes a photoconductor for converting the X-rays into a charge pattern can be reduced by means of a trapping layer which is provided on at least one of the two sides of the photoconductor and reduces the current of charge carriers injected into the photoconductor from this side.

Abstract: A method for the elimination of residual image artifacts from prior image exposure in an x-ray image obtained by exposing an x-ray image detector which includes a photoconductor to imaging x-ray radiation, wherein the residual image artifacts are eliminated by a process which includes obtaining and averaging pre and post exposure image data from the detector and subtracting the averaged pre and post exposure data from the image exposure data.

Abstract: In a method for image reconstruction in imaging technology for the implementation of a fast convolution with the transformation length M while allowing slight over-convolution errors, each of p or 2p out of n measured projections of the length N are convolved with a modified filter kernel h (k) using Fast Fourier Transform (FFT) and Inverse Fast Fourier Transform (IFFT) simultaneously in one step.

Abstract: A device for forming X-ray images, includes an X-ray source for generating an X-ray beam, a photoconductor for converting X-rays into a charge pattern, which photoconductor is provided on a rotationally symmetrically constructed rotatable carrier, a charging device for uniformly charging the surface of the rotating photoconductor prior to the X-ray exposure, a reading unit for converting the charge pattern on the surface of the rotating photoconductor into electric image values after an X-ray exposure, and a housing for the rotating parts which includes an area which is transparent to X-rays.

Abstract: New x-ray photoconductive compositions are disclosed which are certain composites containing (1) inorganic clusters of VB-VIB semiconductors, VB-VIIB semiconductors, IIB-VIB semiconductos, IIB-VB semiconductors, IIIB-VB semiconductors, IIIB-VIB semiconductors, IB-VIB semiconductors and/or IVB-VIIB semiconductors and (2) polymers which are essentially non-carrier-transporting in the absence of x-rays. Also disclosed is an x-ray radiograpy apparatus which employs an image receptor which is a composite of certain inorganic clusters and polymers. A method is disclosed for enhancing the x-ray absorbing efficiency of a polymer which is essentially non-carrier transporting in the absence of x-rays and the x-ray photoconductivity of said polymer by doping the polymer with an effective amount of clusters having a size within the range of from about 0.001 .mu.m to 10 .mu.m.

Abstract: An X-ray apparatus, includes a photoconductor for convening X-rays into a charge pattern and a corona charging device for charging the surface of the photoconductor to a defined potential prior to an X-ray exposure. Deposits of dust on the corona charging device, and the associated artefacts in the X-ray image, are avoided in that there is provided a control unit for operating the corona charging device in a charging mode and in a cleaning mode, a first voltage being applied to the corona charging device in the charging mode whereas in the cleaning mode a second voltage is applied thereto which has, at least temporarily, a polarity which opposes that of the first voltage.

Abstract: The invention relates to a method of generating X-ray images by means of a photoconductor which is provided on a conductive substrate and whose surface potential can be read by means of probes, and also relates to a device suitable for carrying out the method. In order to avoid image artefacts which could be caused by deviating sensitivities of the probes or by frequency-dependent distortions, after the charging of the photoconductor the substrate potential is varied during a test phase. Test data is generated which correspond to the spatial or temporal variation of the potential on the surface of the photoconductor; from this test data there is formed correction data which is stored in order to correct the image data of a subsequent X-ray exposure.

Abstract: An X-ray image capturing element comprising a panel having a layered structure, including a conductive layer comprising a plurality of discrete microplates having dimensions co-extensive with an image pixel and a plurality of access electrodes and electronic components built on the panel, which allow access to the microplates for capturing and reading out a latent radiographic image captured in the panel in the form of stored electrical charges.

Abstract: The invention relates to an arrangement for producing X-ray images, which arrangement comprises an X-ray source (1) for the generation of an X-ray beam (10), a layer (41) sensitive to X-rays and situated on a cylindrical drum (4), and a read unit (5) for converting the X-ray image detected in the layer into electrical image values. In order to improve the X-ray images which can be produced by the arrangement an image processor (21) includes a module (212) for transforming the X-ray image (I) situated on the layer into an X-ray image (I.sub.v) situated in a virtual plane (12), and a module (211) for improving the uniformity of the modulation transfer function (MTF) over the X-ray image produced.

Abstract: A conductive coating on a thin glass strip senses the image signal on a selenium coated photoimaging plate as the plate is scanned with a laser beam. The glass strip is suspended over the surface of the plate with finger-like members. The finger-like members that support the strip are spring loaded downward toward the plate, but are suspended above the plate by a pressurized cushion of air. The strip bends to assume the surface profile of the plate, thus maintaining uniform spacing even though the plate may not be flat and may even have a varying profile along its length.

Abstract: An imaging belt, a dielectric recording sheet, a charger, a transcript roller, and first and second rollers are arranged in a casing. A latent image corresponding to a radiation transmitted image is formed on the imaging belt. At least a fluorescent layer which is sensitive to a radiation to emit light, and a photosensitive layer sensitive to the light emitted by the fluorescent layer are formed on a flexible substrate to constitute the imaging belt. The imaging belt is looped around the first and second rollers, and is driven to rotate. The dielectric recording sheet is rolled, and the latent image formed on the photosensitive layer of the imaging belt is transcribed onto the dielectric recording sheet. The charger charges the surface of the imaging belt at a high voltage. The transcript roller urges the dielectric recording sheet against the imaging belt. Then, the latent image formed on the imaging belt is transcribed onto the dielectric recording sheet.

Abstract: The contrast of an electrographic image or a region of interest of an electrographic image having low contrast is enhanced by developing the electrographic image with toner using a development electrode which is biased to a potential which has a value near the average potential of the image but outside of the range of values of potential corresponding to image features selected for enhancement. The voltage potential of the electrographic image is measured to determine the average potential in the region of interest. The development electrode bias is set at a potential near the average potential but outside of the range of potentials corresponding to the image features selected for enhancement in the region of interest of the image. When developed with toner, the toner image has enhanced contrast. If the image is a xeroradiographic image, diagnostic capability of low contrast regions can be enhanced.

Abstract: A method for capturing and displaying radiographic images. More particularly, the present invention uses a unique microcapacitor matrix structure to hold varying electrical charges representing a latent radiographic image which are subsequently rendered visible through toning.

Abstract: An electrical image signal is generated by providing a toner image on a support, scanning the toner image through a liquid layer in contact with the toner image to produce an optical response and photoelectrically detecting the optical response to produce an electrical image signal.

Abstract: An electrical image signal is produced by an electrographic process including the steps of forming a differential voltage pattern; developing the voltage pattern with a luminescent toner; exciting the developed image to emit radiation; and photoelectrically detecting the emitted radiation to produce an electrical image signal.

Abstract: A plurality of electrometer probes scan the charge pattern of a photoconductor (1), the distance between the electrometer probes (6) and the photoconductor (1) being measured via an alternating voltage applied to the photoconductor (1). The alternating voltage is scanned by the electrometer probes and is filtered out to extract distance measuring signals. The output signals of all electrometer probes (6) are used for determining image values of the X-ray image, the output signals of at least some of the electrometer probes (6) also being used, via a suitable filter (23), for determining the distance measuring signals. An adjusting device adjusts the distance between the electrometer probes (6) and the photoconductor (1) continuously to a reference value, in dependence on the value of the measuring signals, during the scanning operation.

Abstract: A plurality of electrometer probes (3, 4, 5, 6) scan charge patterns of a photoconductor (1) which is locally uniformly charged prior to the X-ray exposure and is discharged by the exposure in dependence on the intensity of the X-rays. The surface of the photoconductor is scanned after the exposure in order to determine the charge density, the electrometer probes (3, 4, 5, 6) forming for each pixel a pixel value which corresponds to the discharge at the relevant pixel to compensate for sensitivity fluctuations of the electrometer probes included is a calibration operation for the sensitivity of all electrometer probes in that two probes (3, 4, 5, 6) scan an identical section (a.sub.1 . . . d.sub.3) of the image, their relative sensitivity used for correcting the pixel values is derived from comparison of the resultant output signals of the probes (3, 4, 5, 6).

Abstract: Processes for preparing ionographic imaging member including providing a flexible, shrinkable tube containing a dielectric film forming polymer having a T.sub.g of at least about -40.degree. C., charge decay of less than about 2 nonocoulombs per cm.sup.2 per second and elastic memory, providing a cylindrical support member having an outer diameter that is less than the inner diameter of the flexible tube, applying a continuous coating on the interior of the tube or on the exterior of the cylindrical support member, the coating comprising a material selected from the group consisting of an electrically conductive material, an adhesive material and mixture thereof, shrinking the tube to bring the inner surface of the tube and the outer surface of the cylindrical support member into intimate physical contact with the continuous coating. This imaging member may be employed in an ionographic imaging process.

Abstract: A tissue analysis device includes first and second plates which are rigid and radiographically transparent, at least one of the plates defining a plurality of pinholes arranged in an evenly spaced pattern to form a rectangular grid, with at least one of the plates including coordinate markings which can be seen both optically and radiographically to create a rectangular coordinate system for defining each section of the grid.

Abstract: The invention relates to a device for producing X-ray images by means of a photoconductor which converts X-rays into a charge pattern, which photoconductor is charged prior to the X-ray exposure, its surface being scanned after the exposure in order to detect the charge pattern. Artefacts are liable to occur in an X-ray image when the exposure directly follows an X-ray exposure during which the photoconductor has received, at least in given areas, a high dose. These artegacts are avoided in accordance with the invention in that there is provided a recharging device which limits the decrease of the charge density on the surface of the photoconductor during the X-ray exposure to a predetermined value.

Abstract: The invention relates to a method of producing an X-ray exposure is provided by a photoconductor, which converts X-radiation into a charge pattern, is evenly charged locally before the X-ray exposure, is discharged by the exposure as a function of the intensity of the X-radiation and the surface of which is scanned after the exposure for detecting the charge density, an image value being formed for each image point, corresponding to the discharge at the image point. The measured image values may be falsified by the self-discharge of the photoconductor induced by X-radiation. Since the self-discharge always proceeds in accordance with the same time laws, the self-discharge effects are corrected utilizing the time of the scanning instants, i.e., position in time with respect to the X-ray exposure and the end of the charging of the photoconductor in conjunction with a characteristic discharge function of the photoconductor and a correction factor.

Abstract: A system for measuring the charge distribution on a photoreceptor plate which has been exposed to X-ray radiations to form an image of an object thereon is disclosed. The system comprises a transparent sensor electrode adapted to be positioned over the photoreceptor plate, means for scanning a pulsed laser beam through the transparent sensor electrode to discharge the photoreceptor surface charge pixel-by-pixel and so induce a corresponding voltage on the sensor electrode to be read by a suitable read-out device, such sensor electrode being of sufficient width so as to achieve good capacitive coupling with the region around the area to be discharged by the laser, and means for moving the sensor electrode or the photoreceptor plate step by step or continuously transversely of the laser scanning direction for reading out the image impressed on the photoreceptor surface.

Abstract: The photoconductive layer of an electrophotographic plate, such as used to record radiographic patterns, is overcoated with a thin dielectric layer having luminescing (e.g., fluorescing or phosphorescing) properties. Upon being uniformly charged and imagewise exposed to actinic radiation (i.e. radiation to which the photoconductive layer responds), the resulting charge pattern is developed with toner. The toner-bearing surface of the electrophotographic plate is irradiated with radiation adapted to excite the luminescent overcoat. The toner image serves, in effect, to mask any luminescence by the underlying overcoat, thereby giving rise to a luminescent contrast image which may be recovered by laser scanning or CCD techniques, or photographed directly.

Abstract: A method is disclosed for producing a X-ray image by a photoconductor which converts X-rays into a charge pattern and which is uniformly charged prior to the X-ray exposure and is discharged during the X-ray exposure as a function of the intensity of the X-rays, the surface of the photoconductor being scanned to measure the charge density, for each pixel point there being formed an image value which is dependent on the discharge at the relevant pixel whereby dot-shaped artefacts in the X-ray image may appear.

Abstract: A method and apparatus for producing an X-ray exposure by means of a photoconductor. Photoconductor defect locations which appear as artefacts in the X-ray image are eliminated by subtracting a compensated dark discharge image from the X-ray image.

Abstract: An improved system for the automatic development of large xeroradiographic images. The system is arranged from left to right in the following order: the development station, the transfer station, the cleaning station, the input and output stations and the elevator. The transport system has two main levels, one to carry the exposed plate over the station to the left, the other to carry the plate through the stations to the right to develop an image. The top of the elevator serves as a relocation station and plates are stored in the bottom of the elevator. To save additional space, the development station moves to the left as the plate passes over it to the right.

Abstract: An apparatus for contact-free measurement of electrical charge images of the type generated on a storage plate as transmission images by means of electro-radiographic recording methods has a matrix of dynamically functioning probes, such as Kelvin probes, for scanning the effect of the electrostatic induction caused by the image on the storage plate, the outputs of the probes being amplified and supplied to a display device such as a picture screen. The individual probes of the matrix are electrically conductive elements and a mechanical oscillation is generated between the charge image and the probes in the field to be measured either by oscillating the probes or by oscillating the storage plate. The charge amounts electrostatically induced in the probes are tapped as the image signals.

Abstract: The invention relates to a photographic apparatus useable, for example, in medical radiodiagnostics, with a three-layer system lying between two electrodes, to which a d-c voltage is applied. The two outer layers are photoconductors and the middle layer consists of a material in which charge carriers can be stored. An image radiated from one side can be read out from the other side in the form of an electric pulse sequence by scanning by means of a light beam and can be reproduced on a television screen. The invention provides a storage layer which has areas in which charge carriers adhere and that on the side of the system on which the image is radiated in the electrode has the same polarity as the charge carriers for which the storage layer has traps.

Abstract: Radiographic imaging method and apparatus are disclosed which include a gas gap formed between closely spaced dielectric and photoconductor surfaces, across which gap a uniform strength electric field is applied. Counting gas is supplied to the gas gap, and penetrating radiation, such as X-ray radiation, is directed onto the photoconductor through an object to be examined. Photons absorbed in the photoconductor induce electron-hole pairs resulting in increased localized conductivity thereof and localized intensification of the electric field across the gas gap to a level for production of gas discharge across the gap. Ion amplification by Townsend cascade enhances charge transfer in the gas gap. An apertured platen may be provided against which dielectric imaging paper is held by gas pressure to facilitate formation of the narrow, substantially uniform width, gas gap. A charge image is produced on the dielectric imaging surface which then is developed using conventional xerographic developing techniques.

Abstract: An x-ray imaging system for intraoral dental radiography. The imaging process is based on xeroradiographic principles, the surface of a small photoconductive plate being electrically charged. After insertion into a carrier, to form a light-tight cassette, the photoconductive plate is placed in a patient's mouth and x-ray exposed. The cassette, and the resultant electrostatic charge image therein, is inserted into the system processor, the photoconductive plate removed and transported to a developer station wherein the image is developed using liquid toner. The toner image is then dried and transferred from the photoconductive plate by using a transparent adhesive material and fixed to a white plastic substrate, forming an image carrier wherein the image can be viewed in reflectance or transmittance. After cleaning, the photoconductive plate is available for reuse. The system has a storage compartment for receiving cleaned photoconductive plates of various sizes for subsequent insertion into an empty cassette.