X-ray examination apparatus and method for forming an X-ray image

An X-ray examination apparatus which includes an X-ray source (11),

• an X-ray detector (13) including sensor elements for converting X-ray in electrical charges and a processing unit (2) for the correction of image data and a defect detection unit (3) for the detection of image defects that can be detected on the basis of image parameters that can be extracted from image data arising during clinical examinations and is suitable to adapt, in dependence on the detected image defects, the processing parameters (18–21) used in the processing unit (2), characterized in that for the detection of image defects caused by defective sensor elements the defect detection unit (3) includes
• a filter unit (37) for filtering the image data,
• a unit (35) for averaging the filtered image data,
• a comparison unit (36) for comparing the filtered and averaged image data with a threshold value in order to form a defect table identifying defective pixels in the image data, and
• a processing unit (2) for correcting the defective pixels identified in the defect table by means of a correction table (20) to obtain corrected pixel values and applying the corrected pixel values to the image data from the X-ray detector (13), wherein the correction table (20) is based on a defect table, wherein the defect detection unit (3) calculates a defect table which is compared with the defect table on which the correction table (20) is based, and wherein in the case of a deviation between the two defect tables, the defect table upon which the correction table (20) is based is replaced, as well as the correction table (20) for the correction of defective pixels.