Abstract: Systems and methods are provided for managing power consumption of a medical imaging detector by the use of triggering signals, environmental condition data, and/or determination of a variable time interval triggering event that is unique for each power consumption state. Systems and methods are provided for managing power and temperature of a device, after receiving a request for a function to be performed by the device determining an “on” trigger component, an “off” trigger component, associated circuits for performing the received function, providing power to the associated circuits upon the occurrence of the “on” trigger component, and removing power to the associated circuits upon the occurrence of the “off” trigger component. Further, an instruction is described for determining and displaying a variable time interval that is indicative of a time to change from one state to a desired state.

Abstract: Systems, methods and apparatus are provided through which in some embodiments the line time of an X-Ray detector is dynamically selected so as to nullify an aliased interference signal. The frequency of a noise signal generated by a source external to the digital X-ray detector is determined and, based on the determined frequency, the line time of the digital X-ray is adjusted so as to compensate for the interfering noise. The frequency of the noise can be directly determined from an electromagnetic interference (EMI) sensor or derived through analysis of the power spectrum of the noise signal.

Abstract: Systems and methods are provided for managing power consumption of a medical imaging detector by the use of triggering signals, environmental condition data, and/or determination of a variable time interval triggering event that is unique for each power consumption state. Systems and methods are provided for managing power and temperature of a device, after receiving a request for a function to be performed by the device determining an “on” trigger component, an “off” trigger component, associated circuits for performing the received function, providing power to the associated circuits upon the occurrence of the “on” trigger component, and removing power to the associated circuits upon the occurrence of the “off” trigger component. Further, an instruction is described for determining and displaying a variable time interval that is indicative of a time to change from one state to a desired state.

Abstract: An apparatus for detecting X-rays comprises a scintillator which emits a plurality of photoelectrons upon being impacted by an X-ray photon. The photoelectrons are amplified in a gas electron multiplier and the resultant photoelectrons are accumulated on a two dimensional array of charge collection electrodes. Electrical signals are produced which indicate the quantity of photoelectrons which strike each charge collection electrode. A processor determines a location of the X-ray photon strike by analyzing the spatial distribution of the photoelectrons accumulated by the array of charge collection electrodes. The intensity of the X-ray photon is determined from the number of accumulated photoelectrons.

Abstract: An apparatus for detecting X-rays comprises a scintillator which emits a plurality of photoelectrons upon being impacted by an X-ray photon. The photoelectrons are amplified in a gas electron multiplier and the resultant photoelectrons are accumulated on a two dimensional array of charge collection electrodes. Electrical signals are produced which indicate the quantity of photoelectrons which strike each charge collection electrode. A processor determines a location of the X-ray photon strike by analyzing the spatial distribution of the photoelectrons accumulated by the array of charge collection electrodes. The intensity of the X-ray photon is determined from the number of accumulated photoelectrons.

Abstract: A technique for adjusting the dynamic range in an imaging system includes balancing of pure gray level processing with pure frequency processing to reduce the brightness of light regions in an image and to maintain contrast in darker regions. The technique applies unsharp masking in which a set of parameter values are used based upon smoothed pixel values for an image. The unsharp masking parameters may be substantially zero below a threshold, and increase nonlinearly above the threshold. A set of brightness control parameters are then used to adjust an output value for each pixel to a desired dynamic range. The brightness control parameters may also be nonlinear.

Abstract: An x-ray system (14) including a source of x-rays (15) and a detector (22) monitors the detector with a control (36) that calibrates the detector during a calibration phase of operation and powers the detector during use phases of operation occurring at different times. A processor (28, 36) reads the data created by the pixel elements, analyzes the data and identifies pixel elements corresponding to data indicating defective pixel elements during the calibration phase of operation and during a predetermined portion of a plurality of the use phases of operation.

Abstract: An x-ray system used to acquire successive images is provided. The x-ray system includes an x-ray source for generating x-rays which are detected by a detector. The detector comprises detector elements that store levels of charge and are arranged in rows and columns. An image processor is used to sense the levels of charge stored by the detector elements. First and second offset image memories are included in the image processor. The first offset image memory stores offset image data for a first mode of operation and a second offset image memory stores offset image data for a second mode of operation.

Abstract: A method is provided for identifying detector elements in a solid state X-ray detector susceptible to causing line artifacts due to faulty detector elements that leak charge. A portion of the X-ray detector is covered by a radiation occluding material and the detector is exposed to a level of radiation sufficient to reach a predetermined threshold in the exposed portion of the detector. An image representative of the radiation is acquired and further analyzed to determine whether line artifacts exist. Data lines found to exhibit line artifacts are stored in the image processor.

Abstract: An x-ray system (14) including a source of x-rays (15) and a detector (22) monitors the detector with a control (36) that calibrates the detector during a calibration phase of operation and powers the detector during use phases of operation occurring at different times. A processor (28, 36) reads the data created by the pixel elements, analyzes the data and identifies pixel elements corresponding to data indicating defective pixel elements during the calibration phase of operation and during a predetermined portion of a plurality of the use phases of operation.

Abstract: A method is provided for identifying detector elements in a solid state X-ray detector susceptible to causing line artifacts due to faulty detector elements that leak charge. A portion of the X-ray detector is covered by a radiation occluding material and the detector is exposed to a level of radiation sufficient to reach a predetermined threshold in the exposed portion of the detector. An image representative of the radiation is acquired and further analyzed to determine whether line artifacts exist. Data lines found to exhibit line artifacts are stored in the image processor.

Abstract: Automated measurement of changes in detective quantum efficiency (DQE) within an x-ray detector. The calculation of relative DQE changes is limited to the measurement of two quantities, namely MTF(f) and NPS(f). The measurement of MTF is obtained using an image quality phantom technique. The measurement of NPS includes the use of a flat field phantom, and data can be obtained during system calibration. Detector degradation and potential field replacement, are determined by monitoring the ratio of DQE as a function of time.

Abstract: A technique for generating replacement values for defective pixels in a digital imaging system includes generating a base values for the defective pixels and a statistical characterizing values which provide consistent statistical relationships with other pixels. The base values may be computed as mean values of pixels surrounding the defective pixels. The statistical characterizing values may be selected to provide deviation from the mean values by a standard deviation of other selected pixels, such as pixels in the neighborhoods of the defective pixels. The technique avoids image artifacts due to inconsistent noise or other statistical characteristics in the pixel replacement values.

Abstract: Automated measurement of changes in detective quantum efficiency (DQE) within an x-ray detector. The calculation of relative DQE changes is limited to the measurement of two quantities, namely MTF(f) and NPS(f). The measurement of MTF is obtained using an image quality phantom technique. The measurement of NPS includes the use of a flat field phantom, and data can be obtained during system calibration. Detector degradation and potential field replacement, are determined by monitoring the ratio of DQE as a function of time.

Abstract: A technique for generating replacement values for defective pixels in a digital imaging system includes generating a base values for the defective pixels and a statistical characterizing values which provide consistent statistical relationships with other pixels. The base values may be computed as mean values of pixels surrounding the defective pixels. The statistical characterizing values may be selected to provide deviation from the mean values by a standard deviation of other selected pixels, such as pixels in the neighborhoods of the defective pixels. The technique avoids image artifacts due to inconsistent noise or other statistical characteristics in the pixel replacement values.

Abstract: A method for minimizing motion artifacts in Dual Energy Subtraction digital radiographic imaging applications by minimizing the time lapse between the two x-ray exposure frames. This is accomplished by acquiring the two x-ray exposure frames relatively consecutively without a corresponding offset frame reading in-between the two x-ray frame exposures. Preferably, the offset frames are acquired following the x-ray exposure frames with a corresponding timing sequence which is correlated to the x-ray frame exposure and reading sequence.

Abstract: A technique for compensating for a retained image includes sampling image data from a digital detector following termination of a first exposure to model decay of the retained image. Based upon the modeled decay, further decay of the retained image is predicted. The predicted decay values are employed to correct or compensate for the decaying retained image in a subsequent exposure. The technique is particularly well suited to compensation of retained images in fluoroscopic exposures following radiographic exposures in a digital x-ray system.

Abstract: A large area solid state x-ray detector employs a number of photodiodes that are charged electrically then discharged by exposure to x-ray. Ghost images resulting from release of charge trapped in photodiodes during prior exposures are eliminated by adjusting the biasing during a reset portion of the imaging cycle. Biasing may be increased to decrease the recharge time or reversed in polarity to evenly discharge the diodes or decreased to preserve the offset so that it may be removed from subsequent images by image processing.

Abstract: Automatic exposure control for an x-ray system using a large area solid state x-ray detector includes an array of photodiodes located behind the x-ray image detector to measure photons passing therethrough. The resulting currents from selective ones of these photodiodes are combined to provide a signal used to control the x-ray exposure.

Abstract: A method for identifying and correcting bad pixels in an x-ray image produced by a large area solid state x-ray detector is disclosed. Initially, each bad pixel is identified. An appropriate correction scheme is then selected from a predetermined list. A correction code is then assigned to each bad pixel, the correction code corresponding to the selected correction scheme. The correction code is stored in a pixel-correction memory, and the correction code for each pixel is read during imaging. Finally, each bad pixel value found during the correction code reading is replaced using the selected correction scheme, and can be immediately displayed.