Non-uniformity emendation technique for amorphous silicon flat-panel detectors used for industrial X-ray digital radiography

This paper proposes a non-uniformity emendation technique to solve the problem of non-linear of detector sensitivity for non-uniformity of amorphous silicon flat-panel detectors based on pixel sensitivity mean value. The technique corrects the testing image with the emendation factors obtained by the fitting of a standard reference group images, captured at a fixed tube voltage and different tube currents, to their mean value according to the concept of linear-fitting emendation. By reducing the input range, it meets the condition of linear system by converting non-linear emendation to linear emendation and actualizes the corresponding pixel fitting linearity. Experimental results indicate that the emendation technique provides higher image elements sensitivity which means wider system dynamic range and better signal-noise-ratio (1.3 times) with the reduction of standard deviation compared with normal linear emendation.