Abstract: A planar image detector for electromagnetic radiation has radiation-sensitive pixel elements arranged in a matrix that has a surface with active pixels for imaging and a surface with correction pixels, not exposed to the radiation for generating correction signals, and with contact surfaces next to the surfaces with the pixels. The surface with the correction pixels is arranged in a different plane from the surface with the active pixels and at one of the sides of the image detector with the contact surfaces of the active pixels.

Abstract: A diagnostic radiography system has an X-ray generator for emitting an X-ray beam, a planar X-tray image converter with a sensor unit with photosensitive pixel elements that are arranged in a matrix and, arranged behind the sensor unit in the direction of radiation, a back-illumination which is formed by elements that are arranged in a matrix are connected to a control device. When the back-illumination is switched on, the output signal of the sensor unit is measured, and the elements of the back-illumination are triggered individually by the control device for homogenization in the sense of producing a uniform output signal.