X-ray imaging using a 320/spl times/240 hybrid GaAs pixel detector

Noise power spectrum of the fixed pattern noise in digital radiography detectors

“…22 Since the gate drivers and amplifiers are not identical, the system gains for each pixel are not uniform. For the scintillator-based indirect detectors, the photodiodes for each pixel also have nonuniform charge collection efficiencies over the detector area, 27 besides the nonuniform system gain problem. Furthermore, the scintillator of the indirect detector has the potential for producing a fixed pattern noise compared to the amorphous photoconductor of direct detectors as follows.…”

“…The fixed pattern noise can be partially reduced using a gain-correction method, which is based on the gain maps or gain correction masks. 2,27,[35][36][37] The gain map is designed by using the average of the uniform exposure images and then the input image is multiplied by the gain map to be corrected. 2,36 However, the nonuniform gain causes the quantizer variance mismatch 38 and thus obstructs optimal uniform quantizer designs for the analog-to-digital conversion.…”

An area efficient readout architecture for photon counting color imaging

“…In such devices, a pixel detector material is bonded to readout electronic circuits. It is possible to use both integrating and photon counting methods to read out the information from the detector [1,2]. However, only the photon counting technique will enable energy discrimination.…”

Evaluation of mixed-signal noise effects in photon-counting X-ray image sensor readout circuits

“…In such devices, a pixel detector material is bonded to readout electronic circuits. Various detection methods are implemented, whereas the readout is usually implemented in CMOS technology as integrating or photon-counting pixel detectors [1,2].…”