X-ray examination apparatus with x-ray image sensor matrix and correction unit

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 ).

1 . An x-ray examination apparatus comprising 
 an x-ray image sensor matrix ( 1 ) for deriving an initial image signal from an x-ray image,    a correction unit ( 2 ) for deriving a corrected image signal from the initial image signal    characterised in that    the correction unit ( 2 ) includes a    memory ( 3 ) for storing correction values and    an arithmetic unit ( 4 ) for computing signal levels of the corrected image signal from signal levels of the initial image signal and at least some of said correction values.    
     
     
         2 . An x-ray examination apparatus as claimed in    claim 1   , characterised in that 
 the correction unit ( 2 ) includes a selection unit ( 5 ) for selecting correction values from the memory ( 3 ) on the basis of exposure parameters.    
     
     
         3 . An x-ray examination apparatus as claimed in    claim 2   , characterised in that 
 the correction unit ( 2 ) is arranged to generate a reference image signal from the x-ray sensor matrix ( 1 ),    the selection unit ( 5 ) is arranged to select the correction values on the basis of the reference image signal.    
     
     
         4 . An x-ray examination apparatus as claimed in any one of the preceding claims, characterised in that 
 the arithmetic unit ( 4 ) is arranged to compute correction values from stored correction values.    
     
     
         5 . An x-ray examination apparatus as claimed in    claim 4   , characterised in that 
 the arithmetic unit ( 4 ) is arranged to interpolate said computed correction values between stored correction values.