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: A planar image detector for electromagnetic rays producing an image for an examination subject has an active surface on a substrate with a matrix of radiation-sensitive pixel elements, and a radiation-sensitive sensor for generating control signals for an exposure control is arranged immediately next to the active area within the rays attenuated by the examination subject.

Abstract: An x-ray examination apparatus comprises an x-ray image sensor matrix (1) for deriving an initial image signal from the x-ray image. The sensor elements of the x-ray sensor matrix convert incident x-rays into electric charges. These electric charges are read-out and converted into the initial image signal. Further a correction unit (2) is provided for correcting the initial image signal, notably for disturbances due to delayed transferred charges, that have been retained in the sensor elements for some time. The correction unit (2) is provided with a memory which stores correction values. Further the correction provided with a selection unit (5) for selecting appropriate correction values from the memory (3).

Abstract: An X-ray examination apparatus for generating an X-ray image of an object, wherein X-ray image generator includes a brightness control input, image processor coupled to the X-ray image generator in order to output a brightness control signal to the control input. The X-ray image generator is provided with an X-ray data output, the image processor is provided with an X-ray data input coupled to the X-ray data output, and the image processor is arranged as calculating system for calculating absorption properties of the object and for generating the brightness control signal in dependence on the absorption properties. Intelligent measuring field selection is now possible on the basis of calculating absorption properties of identifiable objects or parts of objects reproduced in the visible image. Image quality is improved because of brightness control based on more intelligently selected measuring fields.

Abstract: An x-ray examination apparatus comprises an x-ray image sensor matrix (1) for deriving an initial image signal from the x-ray image. The sensor elements of the x-ray sensor matrix convert incident x-rays into electric charges. These electric charges are read-out and converted into the initial image signal. Further a correction unit (2) is provided for correcting the initial image signal, notably for disturbances due to delayed transferred charges, that have been retained in the sensor elements for some time. The correction unit (2) is provided with a memory which stores correction values. Further the correction provided with a selection unit (5) for selecting appropriate correction values from the memory (3).

Abstract: This invention discloses a radiation imager including a plurality of radiation sensing elements operative to provide real-time radiation data and integrated radiation data, and circuitry coupled to the plurality of radiation sensing elements and providing readout of the real time radiation data and readout of the integrated radiation data and being operative to employ the integrated radiation data to provide a radiation image. A method of radiation imaging including the steps of providing a radiation detection module underlying an object to be imaged, exposing the object to be imaged to radiation, and employing the radiation detection module to provide exposure data corresponding to the object at at least two different spatial resolutions is also disclosed.

Abstract: An apparatus using a two-dimensional radiation sensor for acquiring X-ray penetration images or the like. A monitoring radiography is performed with a small dose before a production radiography. A radiographic condition for the production radiography, specifically a radiation emitting period or a tube current of a radiation generator, is computed based on a ratio between a quantity of charges in a region of interest collected from the two-dimensional radiation sensor in time of the monitoring radiography and a desired quantity of charges in the region of interest in time of the production radiography. The production radiography is carried out based on a result of the computation to acquire a high quality image.

Abstract: An X-ray examination apparatus is provided including: an X-ray image means for providing an X-ray image composed of pixels each having a grey value, and a brightness control system which is coupled to the X-ray image means in order to apply a brightness control signal of the image to the X-ray image means. The brightness control system comprises an X-ray image analyzing means for deriving the brightness control signal from a maximum in the number of times that a grey value occurs in the X-ray image. The apparatus provides optimized brightness in the visual image such that a physician is capable of properly examining changes in weakly absorbing tissues or body parts, such as lungs or the like, thus enabling optimized visual analysis.

Abstract: An x-ray radiation stabilization system is provided including an x-ray tube (20) which emits x-ray radiation (22). The x-ray tube (20) has an anode (52), a cathode (50), and a vacuum envelope (54) which houses the anode (52) and the cathode (50). A high-voltage generator (40) is connected to the x-ray tube (20). It supplies a high-voltage electric potential between the cathode (50) and anode (52) such that an electron beam flows therebetween. The electron beam strikes the anode (52) producing the x-ray radiation (22). A reference radiation detector (60) samples a representative portion of the x-ray radiation (22) emitted by the x-ray tube (20) and generates an error signal in response to an intensity of the sampled x-ray radiation (22). A feedback circuit (80) is connected between the reference radiation detector (60) and the high-voltage generator (40).

Abstract: An X-ray diagnostic apparatus forms image data using an arbitrary region in the detectable area of a planar detector having a plurality of X-ray detector elements arrayed in a matrix. An X-ray sensor array for exposure-controlling having a plurality of X-ray sensors arrayed in a matrix overlaps the planar detector. An X-ray controller controls an X-ray tube unit on the basis of an output from the X-ray sensor array in order to optimize the X-ray dose on a subject. A controller selects at least one X-ray sensor in accordance with the position of a partial region where an image is formed. The controller controls at least one of the X-ray sensor array and X-ray controller so as to control the X-ray dose on the basis of an output from the selected X-ray sensor.

Abstract: A digital x-ray image (600) is divided (802) into regions (602), (604) according to a selected (800) exposure compensation profile. Each region (602),(604) includes pixel values indicative of gray-scale levels in that region. The pixel values are used to index entries in one of a plurality of spatial LUTs (312a-n) assigned (804) to that region. Entries in the selected spatial LUT (312a-n) contain new pixel values indicative of a transform (806) on the original pixel values used to index the spatial LUT (312a-n). Original pixel values are replaced (808) with corresponding pixel values from the spatial LUT (312a-n). Each region of the x-ray image (600) needing compensation is transformed (806), in turn, until the entire image (600) is processed.

Abstract: An X-ray examination apparatus comprises an X-ray detector 1 for deriving an image signal and a measurement signal from an X-ray image. The X-ray examination apparatus also includes an exposure control 2 for adjusting the X-ray examination apparatus on the basis of the measurement signal. The X-ray detector is arranged in such a manner that the measurement signal relates mainly to relevant image information in the X-ray image. The X-ray detector is notably provided with a conversion unit 22 for deriving an optical image from the X-ray image. An image sensor with an image pick-up section derives electrical charges from the optical image. The image pick-up section notably derives a measurement component from the electrical charges wherefrom the measurement signal is derived and the image pick-up section also derives an image component from the electrical charges wherefrom the image signal is derived.

Abstract: The x-ray exposure of an image pixel array (202) is measured by assigning to certain pixels (209ep) of the array the task of measuring the level of exposure. A target set (209) of pixels from array (202) is selected and divided into a set of exposure pixels (209ep) and a set of image pixels (209ip). Both sets of pixels generate and collect electrical charges in proportion to the amount of x-ray exposure experienced by them. The charges collected by the exposure pixels (209ep) are continuously read out during the capture of an image and compared with a desired exposure level. Once the desired exposure level is reached, as indicated by the exposure pixels (209ep), the image pixels (209ip) are read out and an image is produced.

Abstract: A method for providing automatic brightness control in a closed loop x-ray imaging system which utilizes an automatic brightness system (ABS) sampling window. The location, size and shape of the ABS sampling window is adjusted in accordance with statistical information including spatial gray scale distribution data derived from the data related to the x-ray system and image being processed, thereby enabling the automatic brightness control to make brightness and power adjustments in accordance with statistical data from the modified ABS sampling window.