General Electric Company

Jean Claude Morvan

Paul Richard Granfors

Scott William Petrick

Lawrence Richard Skrenes

Michael A Juhl

Larry R Skrenes

A large area solid state x-ray detector employs a plurality of cells arranged in rows and columns composed of photodiodes that are charged, exposed to x-rays which deplete their charge in proportion to the exposure, and then recharged to determine the amount of exposure. Fast scanning of the photodiodes consistent with the reduction of dark current effects is obtained without ghost images by employing a non-imaging scan following the imaging scan. The non-imaging scan employs a greater proportion of each scan duration for charge restoration than the imaging scan. In one embodiment simultaneous non-imaging recharging of the photodiodes is performed to substantially reduce this non-imaging time.

Fast scan reset for a large area x-ray detector

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.

Automatic identification and correction of bad pixels in a large area

Row variable offsets in a large area solid state x-ray detector are compensated for. Initially, a calibration is performed to determine the row variable offsets. The calibration is achieved by measuring the average offset of each row. During normal operation, this offset is compensated for in a converting circuit. The required signal range of the converting circuit is consequently reduced.

Method and means for compensating for row variable offsets in a large

A brightness detector is used to control the x-ray exposure and the displayed image level in a diagnostic x-ray imaging system. Initially, a region of interest of an image is specified. The average pixel value within the specified region of interest of the image is then found, ignoring regions below a preselected low signal level threshold. Finally, the average pixel value is fed back to the x-ray generator to control the x-ray exposure. The average pixel value is also used to determine a scaling factor to be applied to the image in order to maintain an optimum brightness level when the desired x-ray exposure cannot be attained.

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Milwaukee, WI, United States of America

Jean Claude Morvan